Arthroplasty/Joint Replacement

Biologic use in orthopedics is a continuously evolving field that complements technical, anatomic, and biomechanical advancements in orthopedics. Biologic agents are receiving increasing attention for their use in augmenting healing of muscles, tendons, ligaments, and osseous structures. As biologic augmentation strategies become increasingly utilized in bony and soft-tissue injuries, research on stem cell use in orthopedics continues to increase. Stem cell-based therapies for the repair or regeneration of muscle and tendon represent a promising technology going forward for numerous diseases.¹

Stem cells by definition are undifferentiated cells that have 4 main characteristics: (1) mobilization during angiogenesis, (2) differentiation into specialized cell types, (3) proliferation and regeneration, and (4) release of immune regulators and growth factors.² Mesenchymal stem cells (MSCs) have garnered the most attention in the field of surgery due to their ability to differentiate into the tissues of interest for the surgeon.³ This includes both bone marrow-derived mesenchymal stem cells (bm-MSCs) and adipose-derived mesenchymal stem cells (a-MSCs). These multipotent stem cells in adults originate from mesenchymal tissues, including bone marrow, tendon, adipose, and muscle tissue.⁴ They are attractive for clinical use because of their multipotent potential and relative ease of growth in culture.⁵ They also exert a paracrine effect to modulate and control inflammation, stimulate endogenous cell repair and proliferation, inhibit apoptosis, and improve blood flow through secretion of chemokines, cytokines, and growth factors.^6,7

Questions exist regarding the best way to administer stem cells, whether systematic administration is possible for these cells to localize to the tissue in need, or more likely if direct application to the pathologic area is necessary.^8,9 A number of sources, purification process, and modes of delivery are available, but the most effective means of preparation and administration are still under investigation. The goal of this review is to illustrate the current state of knowledge surrounding stem cell therapy in orthopedics with a focus on osteoarthritis, tendinopathy, articular cartilage, and enhancement of surgical procedures.

Important Considerations

Common stem cell isolates include embryonic, induced pluripotent, and mesenchymal formulations (Table 1). MSCs can be obtained from multiple sites, including but not limited to the adult bone marrow, adipose, muscular, or tendinous tissues, and their use has been highlighted in the study of numerous orthopedic and nonorthopedic pathologies over the course of the last decade. Research on the use of embryonic stem cells in medical therapy with human implications has received substantial attention, with many ethical concerns by those opposed, and the existence of a potential risk of malignant alterations.^8,10 Amniotic-derived stem cells can be isolated from amniotic fluid, umbilical cord blood, or the placenta and thus do not harbor the same social constraints as the aforementioned embryonic cells; however, they do not harbor the same magnitude of multi-differentiation potential, either.⁴

Adult MSCs are more locally available and easy to obtain for treatment when compared with embryonic and fetal stem cells, and the former has a lower immunogenicity, which allows allogeneic use.¹¹ Safety has been preliminarily demonstrated in use thus far; Centeno and colleagues¹² found no neoplastic tissue generation at the site of stem cell injection after 3 years postinjection for a cohort of patients who were treated with autologous bm-MSCs for various pathologies. Self-limited pain and swelling are the most commonly reported adverse events after use.¹³ However, long-term data are lacking in many instances to definitively suggest the absence of possible complications.

Basic Science

Stem cell research encompasses a wide range of rapidly developing treatment strategies that are applicable to virtually every field of medicine. In general, stem cells can be classified as embryonic stem cells (ESCs), induced pluripotent stem (iPS) cells, or adult-derived MSCs. ESCs are embryonic cells derived typically from fetal tissue, whereas iPS cells are dedifferentiated from adult tissue, thus avoiding many of the ethical and legal challenges imposed by research with ESCs. However, oncogenic and lingering politico-legal concerns with introducing dedifferentiated ESCs or iPS cells into healthy tissue necessitate the development, isolation, and expansion of multi- but not pluripotent stem cell lines.¹⁴ To date, the most advantageous and widely utilized from any perspective are MSCs, which can further differentiate into cartilage, tendon, muscle, and bony tissue.^7,15,16

MSCs are defined by their ability to demonstrate in vitro differentiation into osteoblasts, adipocytes, or chondroblasts, adhere to plastic, express CD105, CD73, and CD90, and not express CD43, CD23, CD14 or CD11b, CD79 or CD19, or HLA-DR.¹⁷ Porada and Almeida-Porada¹⁸ have outlined 6 reasons highlighting the advantages of MSCs: 1) ease of isolation, 2) high differentiation capabilities, 3) strong colony expansion without differentiation loss, 4) immunosuppression following transplantation, 5) powerful anti-inflammatory properties, and 6) their ability to localize to damaged tissue. The anti-inflammatory properties of MSCs are particularly important as they promote allo- and xenotransplantation from donor tissues.^19,20 MSCs can be isolated from numerous sources, including but not limited to bone marrow, periosteum, adipocyte, and muscle.^21-23 Interestingly, the source tissue used to isolate MSCs can affect differentiation capabilities, colony size, and growth rate (Table 2).²⁴ Advantages of a-MSCs include high prevalence and ease of harvest; however, several animal studies have shown inferior results when compared to bm-MSCs.^25-27 More research is needed to determine the ideal source material for MSCs, which will likely depend in part on the procedure for which they are employed.²⁷

Following harvesting, isolation, and expansion, MSC delivery methods for treatments typically consist of either cell-based or tissue engineering approaches. Cell-based techniques involve the injection of MSCs into damaged tissues. Purely cell-based therapy has shown success in limited clinical trials involving knee osteoarthritis, cartilage repair, and meniscal repair.^28-30 However, additional studies with longer follow-up are required to validate these preliminary findings. Tissue engineering approaches involve the construction of a 3-dimensional scaffold seeded with MSCs that is later surgically implanted. While promising in theory, limited and often conflicting data exist regarding the efficacy of tissue-engineered MSC implantation.^31-32 Suboptimal scaffold vascularity is a major limitation to scaffold design, which may be alleviated in part with the advent of 3-dimensional printing and the ability to more precisely alter scaffold architecture.^14,33 Additional limitations include ensuring MSC purity and differentiation potential following harvesting and expansion. At present, the use of tissue engineering with MSCs is promising but it remains a nascent technology with additional preclinical studies required to confirm implant efficacy and safety.

Clinical Entities

Osteoarthritis

MSC therapies have emerged as promising treatment strategies in the setting of early osteoarthritis (OA). In addition to their regenerative potential, MSCs demonstrate potent anti-inflammatory properties, increasing their attractiveness as biologic agents in the setting of OA.³⁴ Over the past decade, multiple human trials have been published demonstrating the efficacy of MSC injections into patients with OA.^35,36 In a study evaluating a-MSC injection into elderly patients (age >65 years) with knee OA, Koh and colleagues²⁹ found that 88% demonstrated improved cartilage status at 2-year follow-up, while no patient underwent a total knee arthroplasty during this time period. In another study investigating patients with unicompartmental knee OA with varus alignment undergoing high tibial osteotomy and microfracture, Wong and colleagues³⁷ reported improved clinical, patient-reported, and magnetic resonance imaging (MRI)-based outcomes in a group receiving a preoperative MSC injection compared to a control group. Further, in a recent randomized control trial of patients with knee osteoarthritis, Vega and colleagues³⁸ reported improved cartilage and quality of life outcomes at 1 year following MSC injection compared to a control group receiving a hyaluronic acid injection. In addition to knee OA, studies have also reported improvement in ankle OA following MSC injection.³⁹ While promising, many of the preliminary clinical studies evaluating the efficacy of MSC therapies in the treatment of OA are hindered by small patient populations and short-term follow-up. Additional large-scale, randomized studies are required and many are ongoing presently in hopes of validating these preliminary findings.³⁶

Tendinopathy

The quality of repaired tissue in primary tendon-to-tendon and tendon-to-bone healing has long been a topic of great interest.⁴⁰ The healing potential of tendons is inferior to that of other bony and connective tissues,⁴¹ with tendon healing typically resulting in a biomechanically and histologically inferior structure to the native tissue.⁴² As such, this has been a particularly salient opportunity for stem cell use with hopes of recapitulating a more normal tendon or tendon enthesis following injury. In addition to the acute injury, there is great interest in the application of stem cells to chronic states of injury such as tendinopathy.

In equine models, the effect of autologous bm-MSCs treatment on tendinopathy of the superficial digital flexor tendon has been studied. Godwin and colleagues⁴³ evaluated 141 race horses with spontaneous superficial digital flexor tendinopathy treated in this manner, and reported a reinjury percentage in these treated horses of just 27.4%, which compared favorably to historical controls and alternative therapeutics. Machova Urdzikova and colleagues⁴⁴ injected MSCs at Achilles tendinopathy locations to augment nonoperative healing in 40 rats, and identified more native histological organization and improved vascularization in comparison to control rat specimens. Oshita and colleagues⁴⁵ reported histologic improvement of tendinopathy findings in 8 rats receiving a-MSCs at the location of induced Achilles tendinopathy that was significantly superior to a control cohort. Bm-MSCs were used by Yuksel and colleagues⁴⁶ in comparison with platelet-rich plasma (PRP) for treatment of Achilles tendon ruptures created surgically in rat models. They demonstrated successful effects with its use in terms of recovery for the tendon’s histopathologic, immunohistochemical, and biomechanical properties, related to significantly greater levels of anti-inflammatory cytokines. However, these aforementioned findings have not been uniform across the literature—other authors have reported findings that MSC transplantation alone did not repair Achilles tendon injury with such high levels of success.⁴⁷

Human treatment of tendinopathies with stem cells has been scarcely studied to date. Pascual-Garrido and colleagues⁴⁸ evaluated 8 patients with refractory patellar tendinopathy treated with injection of autologous bm-MSCs and reported successful results at 2- to 5-year follow-up, with significant improvements in patient-reported outcome measures for 100% of patients. Seven of 8 (87.5%) noted that they would undergo the procedure again.

Articular Cartilage Injury

Chondral injury is a particularly important subject given the limited potential of chondrocytes to replicate or migrate to the site of pathology.⁴⁹ Stem cell use in this setting assists with programmed growth factor release and alteration of the anatomic microenvironment to facilitate regeneration and repair of the chondral surface. Autologous stem cell use through microfracture provides a perforation into the bone marrow and a subsequent fibrin clot formation containing platelets, growth factors, vascular elements, and MSCs.⁵⁰ A similar concept to PRP is currently being explored with bm-MSCs. Isolated bm-MSCs are commonly referred to as bone marrow aspirate or bone marrow aspirate concentrate (BMAC). Commercially available systems are now available to aid in the harvesting and implementation of BMAC. One of the more promising avenues for BMAC implementation is in articular cartilage repair or regeneration due to chondrogenic potential of BMAC when used in isolation or when combined with microfracture, chondrocyte transfer, or collagen scaffolds.^19,51 Synovial-derived stem cells as an additional source for stem cell use has demonstrated excellent chondrogenic potential in animal studies with full-thickness lesion healing and native-appearing cartilage histologically.⁵² Incorporation of a-MSCs into scaffolds for surgical implantation has demonstrated success in repairing full-thickness chondral defects with continuous joint surface and extracellular proteins, surface markers, and gene products similar to the native cartilage in animal models.^53,54 In light of the promising basic science and animal studies, clinical studies have begun to emerge.^55-57

Fortier and colleagues⁵⁸ found MRI and histologic evidence of full-thickness chondral repair and increased integration with neighboring cartilage when BMAC was concurrently used at the time of microfracture in an equine model. Fortier and colleagues⁵⁸ also demonstrated greater healing in equine models with acute full-thickness cartilage defects treated by microfracture with MSCs than without delivery of MSCs. Kim and colleagues^59,60 similarly reported superiority in clinical outcomes for patients with osteochondral lesions of the talus treated with marrow stimulation and MSC injection than by the former in isolation.

In humans, stem cell use for chondral repair has additionally proven promising. A systematic review of the literature suggested good to excellent overall outcomes for the treatment of moderate focal chondral defects with BMAC with or without scaffolds and microfracture with inclusion of 8 total publications.⁶¹ This review included Gobbi and colleagues,⁶² who prospectively treated 15 patients with a mean focal chondral defect size of 9.2 cm² about the knee. Use of BMAC covered with a collagen I/III matrix produced significant improvements in patient-reported outcome scores and MRI demonstrated complete hyaline-like cartilage coverage in 80%, with second-look arthroscopy demonstrating normal to nearly normal tissue. Gobbi and colleagues⁵⁵ also found evidence for superiority of chondral defects treated with BMAC compared to matrix-induced autologous chondrocyte implantation (MACI) for patellofemoral lesions in 37 patients (MRI showed complete filling of defects in 81% of BMAC-treated patients vs 76% of MACI-treated patients).

Meniscal Repair

Clinical application of MSCs in the treatment of meniscal pathology is evolving as well. ASCs have been added to modify the biomechanical environment of avascular zone meniscal tears at the time of suture repair in a rabbit, and have demonstrated increased healing rates in small and larger lesions, although the effect lessens with delay in repair.⁶³ Angele and colleagues⁶⁴ treated meniscal defects in a rabbit model with scaffolds with bm-MSCs compared with empty scaffolds or control cohorts and found a higher proportion of menisci with healed meniscus-like fibrocartilage when MSCs were utilized.

In humans, Vangsness and colleagues³⁰ treated knees with partial medial meniscectomy with allogeneic stem cells and reported an increase in meniscal volume and decrease in pain in those patients when compared to a cohort of knees treated with hyaluronic acid. Despite promising early results, additional clinical studies are necessary to determine the external validity and broad applicability of stem cell use in meniscal repair.

Rotator Cuff Repair

The number of local resident stem cells at the site of rotator cuff tear has been shown to decrease with tear size, chronicity, and degree of fatty infiltration, suggesting that those with the greatest need for a good reparative environment are those least equipped to heal.⁶⁵ The need for improvement in this domain is related to the still relatively high re-tear rate after rotator cuff repair despite improvements in instrumentation and surgical technique.⁶⁶ The native fibrocartilaginous transition zone between the humerus and the rotator cuff becomes a fibrovascular scar tissue after rupture and repair with poorer material properties than the native tissue.⁶⁷ Thus, a-MSCs have been evaluated in this setting to determine if the biomechanical and histological properties of the repair may improve.⁶⁸

In rat models, Valencia Mora and colleagues⁶⁸ reported on the application of a-MSCs in a rat rotator cuff repair model compared to an untreated group. They found no differences between those treated rats and those without a-MSCs use in terms of biomechanical properties of the tendon-to-bone healing, but those with stem cell use had less inflammation shown histologically (diminished presence of edema and neutrophils) at 2- and 4-week time points, which the authors suggested may lead to a more elastic repair and less scar at the bone-tendon healing site. Oh and colleagues¹ evaluated the use of a-MSCs in a rabbit subscapularis tear model, and reported significantly reduced fatty infiltration at the site of chronic rotator cuff tear after repair with its application at the repair site; while the load-to-failure was higher in those rabbits with ASCs administration, it was short of reaching statistical significance. Yokoya and colleagues⁶⁹ demonstrated regeneration of rotator cuff tendon-to-bone insertional site anatomy and in the belly of the cuff tendon in a rabbit model with MSCs applied at the operative site. However, Gulotta and colleagues⁷⁰ did not see the same improvement in their similar study in the rat model; these authors failed to see improvement in structure, strength, or composition of the tendinous attachment site despite addition of MSCs.

Clinical studies on augmented rotator cuff repair have also found mixed results. MSCs for this purpose have been cultivated from arthroscopic bone marrow aspiration of the proximal humerus⁷¹ and subacromial bursa⁷² with successful and reproducibly high concentrations of stem cells. Hernigou and colleagues⁷³ found a significant improvement in rate of healing (87% intact cuffs vs 44% in the control group) and repair surface tendon integrity (via ultrasound and MRI) for patients at a minimum of 10 years after rotator cuff repair with MSC injection at the time of surgery. The authors found a direct correlation in these outcomes with the number of MSCs injected at the time of repair. Ellera Gomes and colleagues⁷⁴ injected bm-MSCs obtained from the iliac crest into the tendinous repair site in 14 consecutive patients with full-thickness rotator cuff tears treated by transosseous sutures via a mini-open approach. MRI demonstrated integrity of the repair site in all patients at more than 1-year follow-up.

Achilles Tendon Repair

The goal with stem cell use in Achilles repair is to accelerate the healing and rehabilitation. Several animal studies have demonstrated improved mechanical properties and collagen composition of tendon repairs augmented with stem cells, including Achilles tendon repair in a rat model. Adams and colleagues⁷⁵ compared suture alone (36 tendons) to suture plus stem cell concentrate injection (36 tendons) and stem cell loaded suture (36 tendons) in Achilles tendon repair with rat models. The suture-alone cohort had lower ultimate failure loads at 14 days after surgery, indicating biomechanical superiority with stem cell augmentation means. Transplantation of hypoxic MSCs at the time of Achilles tendon repair may be a promising option for superior biomechanical failure loads and histologic findings as per recent rat model findings by Huang and colleagues.⁷⁶ Yao and colleagues⁷⁷ demonstrated increased strength of suture repair for Achilles repair in rat models at early time points when using MSC-coated suture in comparison to standard suture, and suggested that the addition of stem cells may improve early mechanical properties during the tendon repair process. A-MSC addition to PRP has provided significantly increased tensile strength to rabbit models with Achilles tendon repair as well.⁷⁸

In evaluation of stem cell use for this purpose with humans, Stein and colleagues⁷⁹ reviewed 28 sports-related Achilles tendon ruptures in 27 patients treated with open repair and BMAC injection. At a mean follow-up of 29.7 months, the authors reported no re-ruptures, with 92% return to sport at 5.9 months, and excellent clinical outcomes. This small cohort study found no adverse outcomes related to the BMAC addition, and thus proposed further study of the efficacy of stem cell treatment for Achilles tendon repair.

Anterior Cruciate Ligament Reconstruction

Bm-MSCs genetically modified with bone morphogenetic protein 2 (BMP2) and basic fibroblast growth factor (bFGF) have shown great promise in improvement of the formation of mechanically sound tendon-bone interface in anterior cruciate ligament (ACL) reconstruction.⁸⁰ Similar to the other surgical procedures mentioned in this review, animal studies have successfully evaluated the augmentation of osteointegration of tendon to bone in the setting of ACL reconstruction. Jang and colleagues³ investigated the use of nonautologous transplantation of human umbilical cord blood-derived MSCs in a rabbit ACL reconstruction model. The authors demonstrated a lack of immune rejection, and enhanced tendon-bone healing with broad fibrocartilage formation at the transition zone (similar to the native ACL) and decreased femoral and tibial tunnel widening as compared to a control cohort at 12-weeks after surgery. In a rat model, Kanaya and colleagues⁸¹ reported improved histological scores and slight improvements in biomechanical integrity of partially transected rat ACLs treated with intra-articular MSC injection. Stem cell use in the form of suture-supporting scaffolds seeded with MSCs has been evaluated in a total ACL transection rabbit model; the authors of this report demonstrated total ACL regeneration in one-third of samples treated with this augmentation option, in comparison to complete failure in all suture and scaffold alone groups.⁸²

The use of autologous MSCs in ACL healing remains limited to preclinical research and small case series of patients. One human trial by Silva and colleagues⁸³ evaluated the graft-to-bone site of healing in ACL reconstruction for 20 patients who received an intraoperative infiltration of their graft with adult bm-MSCs. MRI and histologic analysis showed no difference in comparison to control groups, but the authors’ conclusion proposed that the number of stem cells injected might have been too minimal to show a clinical effect.

Other Applications

Although outside the scope of this article, stem cells have demonstrated efficacy in the treatment of a number of osseous clinical entities. This includes the treatment of fracture nonunion, augmentation of spinal fusion, and assistance in the treatment of osteonecrosis.⁸⁴

Summary

As a scientific community, our understanding of the use of stem cells, their nuances, and their indications has expanded dramatically over the last several years. Stem cell treatment has particularly infiltrated the world of operative and nonoperative sports medicine, given in part the active patient population seeking greater levels of improvement.⁸⁵ Stem cell therapy offers a potentially effective therapy for a multitude of pathologies because of these cells’ anti-inflammatory, immunoregulatory, angiogenic, and paracrine effects.⁸⁶ It thus remains a very dynamic option in the study of musculoskeletal tissue regeneration. While the potential exists for stem cell use in daily surgery practices, it is still premature to predict whether this can be expected.

The ideal stem cell sources (including allogeneic or autologous), preparation, cell number, timing, and means of application continue to be evaluated, as well as those advantageous pathologies that can benefit from the technology. In order to better answer these pertinent questions, we need to make sure we have a safe, economic, and ethically acceptable means for stem cell translational research efforts. More high-level studies with standardized protocols need to be performed. It is necessary to improve national and international collaboration in research, as well as collaboration with governing bodies, to attempt to further scientific advancement in this field of research.⁴⁹ Further study on embryonic stem cell use may be valuable as well, pending governmental approval. Finally, more dedicated research efforts must be placed on the utility of adjuncts with stem cell use, including PRP and scaffolds, which may increase protection, nutritional support, and mechanical stimulation of the administered stem cells.

Biologic use in orthopedics is a continuously evolving field that complements technical, anatomic, and biomechanical advancements in orthopedics. Biologic agents are receiving increasing attention for their use in augmenting healing of muscles, tendons, ligaments, and osseous structures. As biologic augmentation strategies become increasingly utilized in bony and soft-tissue injuries, research on stem cell use in orthopedics continues to increase. Stem cell-based therapies for the repair or regeneration of muscle and tendon represent a promising technology going forward for numerous diseases.¹

Stem cells by definition are undifferentiated cells that have 4 main characteristics: (1) mobilization during angiogenesis, (2) differentiation into specialized cell types, (3) proliferation and regeneration, and (4) release of immune regulators and growth factors.² Mesenchymal stem cells (MSCs) have garnered the most attention in the field of surgery due to their ability to differentiate into the tissues of interest for the surgeon.³ This includes both bone marrow-derived mesenchymal stem cells (bm-MSCs) and adipose-derived mesenchymal stem cells (a-MSCs). These multipotent stem cells in adults originate from mesenchymal tissues, including bone marrow, tendon, adipose, and muscle tissue.⁴ They are attractive for clinical use because of their multipotent potential and relative ease of growth in culture.⁵ They also exert a paracrine effect to modulate and control inflammation, stimulate endogenous cell repair and proliferation, inhibit apoptosis, and improve blood flow through secretion of chemokines, cytokines, and growth factors.^6,7

Questions exist regarding the best way to administer stem cells, whether systematic administration is possible for these cells to localize to the tissue in need, or more likely if direct application to the pathologic area is necessary.^8,9 A number of sources, purification process, and modes of delivery are available, but the most effective means of preparation and administration are still under investigation. The goal of this review is to illustrate the current state of knowledge surrounding stem cell therapy in orthopedics with a focus on osteoarthritis, tendinopathy, articular cartilage, and enhancement of surgical procedures.

Important Considerations

Common stem cell isolates include embryonic, induced pluripotent, and mesenchymal formulations (Table 1). MSCs can be obtained from multiple sites, including but not limited to the adult bone marrow, adipose, muscular, or tendinous tissues, and their use has been highlighted in the study of numerous orthopedic and nonorthopedic pathologies over the course of the last decade. Research on the use of embryonic stem cells in medical therapy with human implications has received substantial attention, with many ethical concerns by those opposed, and the existence of a potential risk of malignant alterations.^8,10 Amniotic-derived stem cells can be isolated from amniotic fluid, umbilical cord blood, or the placenta and thus do not harbor the same social constraints as the aforementioned embryonic cells; however, they do not harbor the same magnitude of multi-differentiation potential, either.⁴

Adult MSCs are more locally available and easy to obtain for treatment when compared with embryonic and fetal stem cells, and the former has a lower immunogenicity, which allows allogeneic use.¹¹ Safety has been preliminarily demonstrated in use thus far; Centeno and colleagues¹² found no neoplastic tissue generation at the site of stem cell injection after 3 years postinjection for a cohort of patients who were treated with autologous bm-MSCs for various pathologies. Self-limited pain and swelling are the most commonly reported adverse events after use.¹³ However, long-term data are lacking in many instances to definitively suggest the absence of possible complications.

Basic Science

Stem cell research encompasses a wide range of rapidly developing treatment strategies that are applicable to virtually every field of medicine. In general, stem cells can be classified as embryonic stem cells (ESCs), induced pluripotent stem (iPS) cells, or adult-derived MSCs. ESCs are embryonic cells derived typically from fetal tissue, whereas iPS cells are dedifferentiated from adult tissue, thus avoiding many of the ethical and legal challenges imposed by research with ESCs. However, oncogenic and lingering politico-legal concerns with introducing dedifferentiated ESCs or iPS cells into healthy tissue necessitate the development, isolation, and expansion of multi- but not pluripotent stem cell lines.¹⁴ To date, the most advantageous and widely utilized from any perspective are MSCs, which can further differentiate into cartilage, tendon, muscle, and bony tissue.^7,15,16

MSCs are defined by their ability to demonstrate in vitro differentiation into osteoblasts, adipocytes, or chondroblasts, adhere to plastic, express CD105, CD73, and CD90, and not express CD43, CD23, CD14 or CD11b, CD79 or CD19, or HLA-DR.¹⁷ Porada and Almeida-Porada¹⁸ have outlined 6 reasons highlighting the advantages of MSCs: 1) ease of isolation, 2) high differentiation capabilities, 3) strong colony expansion without differentiation loss, 4) immunosuppression following transplantation, 5) powerful anti-inflammatory properties, and 6) their ability to localize to damaged tissue. The anti-inflammatory properties of MSCs are particularly important as they promote allo- and xenotransplantation from donor tissues.^19,20 MSCs can be isolated from numerous sources, including but not limited to bone marrow, periosteum, adipocyte, and muscle.^21-23 Interestingly, the source tissue used to isolate MSCs can affect differentiation capabilities, colony size, and growth rate (Table 2).²⁴ Advantages of a-MSCs include high prevalence and ease of harvest; however, several animal studies have shown inferior results when compared to bm-MSCs.^25-27 More research is needed to determine the ideal source material for MSCs, which will likely depend in part on the procedure for which they are employed.²⁷

Following harvesting, isolation, and expansion, MSC delivery methods for treatments typically consist of either cell-based or tissue engineering approaches. Cell-based techniques involve the injection of MSCs into damaged tissues. Purely cell-based therapy has shown success in limited clinical trials involving knee osteoarthritis, cartilage repair, and meniscal repair.^28-30 However, additional studies with longer follow-up are required to validate these preliminary findings. Tissue engineering approaches involve the construction of a 3-dimensional scaffold seeded with MSCs that is later surgically implanted. While promising in theory, limited and often conflicting data exist regarding the efficacy of tissue-engineered MSC implantation.^31-32 Suboptimal scaffold vascularity is a major limitation to scaffold design, which may be alleviated in part with the advent of 3-dimensional printing and the ability to more precisely alter scaffold architecture.^14,33 Additional limitations include ensuring MSC purity and differentiation potential following harvesting and expansion. At present, the use of tissue engineering with MSCs is promising but it remains a nascent technology with additional preclinical studies required to confirm implant efficacy and safety.

Clinical Entities

Osteoarthritis

MSC therapies have emerged as promising treatment strategies in the setting of early osteoarthritis (OA). In addition to their regenerative potential, MSCs demonstrate potent anti-inflammatory properties, increasing their attractiveness as biologic agents in the setting of OA.³⁴ Over the past decade, multiple human trials have been published demonstrating the efficacy of MSC injections into patients with OA.^35,36 In a study evaluating a-MSC injection into elderly patients (age >65 years) with knee OA, Koh and colleagues²⁹ found that 88% demonstrated improved cartilage status at 2-year follow-up, while no patient underwent a total knee arthroplasty during this time period. In another study investigating patients with unicompartmental knee OA with varus alignment undergoing high tibial osteotomy and microfracture, Wong and colleagues³⁷ reported improved clinical, patient-reported, and magnetic resonance imaging (MRI)-based outcomes in a group receiving a preoperative MSC injection compared to a control group. Further, in a recent randomized control trial of patients with knee osteoarthritis, Vega and colleagues³⁸ reported improved cartilage and quality of life outcomes at 1 year following MSC injection compared to a control group receiving a hyaluronic acid injection. In addition to knee OA, studies have also reported improvement in ankle OA following MSC injection.³⁹ While promising, many of the preliminary clinical studies evaluating the efficacy of MSC therapies in the treatment of OA are hindered by small patient populations and short-term follow-up. Additional large-scale, randomized studies are required and many are ongoing presently in hopes of validating these preliminary findings.³⁶

Tendinopathy

The quality of repaired tissue in primary tendon-to-tendon and tendon-to-bone healing has long been a topic of great interest.⁴⁰ The healing potential of tendons is inferior to that of other bony and connective tissues,⁴¹ with tendon healing typically resulting in a biomechanically and histologically inferior structure to the native tissue.⁴² As such, this has been a particularly salient opportunity for stem cell use with hopes of recapitulating a more normal tendon or tendon enthesis following injury. In addition to the acute injury, there is great interest in the application of stem cells to chronic states of injury such as tendinopathy.

In equine models, the effect of autologous bm-MSCs treatment on tendinopathy of the superficial digital flexor tendon has been studied. Godwin and colleagues⁴³ evaluated 141 race horses with spontaneous superficial digital flexor tendinopathy treated in this manner, and reported a reinjury percentage in these treated horses of just 27.4%, which compared favorably to historical controls and alternative therapeutics. Machova Urdzikova and colleagues⁴⁴ injected MSCs at Achilles tendinopathy locations to augment nonoperative healing in 40 rats, and identified more native histological organization and improved vascularization in comparison to control rat specimens. Oshita and colleagues⁴⁵ reported histologic improvement of tendinopathy findings in 8 rats receiving a-MSCs at the location of induced Achilles tendinopathy that was significantly superior to a control cohort. Bm-MSCs were used by Yuksel and colleagues⁴⁶ in comparison with platelet-rich plasma (PRP) for treatment of Achilles tendon ruptures created surgically in rat models. They demonstrated successful effects with its use in terms of recovery for the tendon’s histopathologic, immunohistochemical, and biomechanical properties, related to significantly greater levels of anti-inflammatory cytokines. However, these aforementioned findings have not been uniform across the literature—other authors have reported findings that MSC transplantation alone did not repair Achilles tendon injury with such high levels of success.⁴⁷

Human treatment of tendinopathies with stem cells has been scarcely studied to date. Pascual-Garrido and colleagues⁴⁸ evaluated 8 patients with refractory patellar tendinopathy treated with injection of autologous bm-MSCs and reported successful results at 2- to 5-year follow-up, with significant improvements in patient-reported outcome measures for 100% of patients. Seven of 8 (87.5%) noted that they would undergo the procedure again.

Articular Cartilage Injury

Chondral injury is a particularly important subject given the limited potential of chondrocytes to replicate or migrate to the site of pathology.⁴⁹ Stem cell use in this setting assists with programmed growth factor release and alteration of the anatomic microenvironment to facilitate regeneration and repair of the chondral surface. Autologous stem cell use through microfracture provides a perforation into the bone marrow and a subsequent fibrin clot formation containing platelets, growth factors, vascular elements, and MSCs.⁵⁰ A similar concept to PRP is currently being explored with bm-MSCs. Isolated bm-MSCs are commonly referred to as bone marrow aspirate or bone marrow aspirate concentrate (BMAC). Commercially available systems are now available to aid in the harvesting and implementation of BMAC. One of the more promising avenues for BMAC implementation is in articular cartilage repair or regeneration due to chondrogenic potential of BMAC when used in isolation or when combined with microfracture, chondrocyte transfer, or collagen scaffolds.^19,51 Synovial-derived stem cells as an additional source for stem cell use has demonstrated excellent chondrogenic potential in animal studies with full-thickness lesion healing and native-appearing cartilage histologically.⁵² Incorporation of a-MSCs into scaffolds for surgical implantation has demonstrated success in repairing full-thickness chondral defects with continuous joint surface and extracellular proteins, surface markers, and gene products similar to the native cartilage in animal models.^53,54 In light of the promising basic science and animal studies, clinical studies have begun to emerge.^55-57

Fortier and colleagues⁵⁸ found MRI and histologic evidence of full-thickness chondral repair and increased integration with neighboring cartilage when BMAC was concurrently used at the time of microfracture in an equine model. Fortier and colleagues⁵⁸ also demonstrated greater healing in equine models with acute full-thickness cartilage defects treated by microfracture with MSCs than without delivery of MSCs. Kim and colleagues^59,60 similarly reported superiority in clinical outcomes for patients with osteochondral lesions of the talus treated with marrow stimulation and MSC injection than by the former in isolation.

In humans, stem cell use for chondral repair has additionally proven promising. A systematic review of the literature suggested good to excellent overall outcomes for the treatment of moderate focal chondral defects with BMAC with or without scaffolds and microfracture with inclusion of 8 total publications.⁶¹ This review included Gobbi and colleagues,⁶² who prospectively treated 15 patients with a mean focal chondral defect size of 9.2 cm² about the knee. Use of BMAC covered with a collagen I/III matrix produced significant improvements in patient-reported outcome scores and MRI demonstrated complete hyaline-like cartilage coverage in 80%, with second-look arthroscopy demonstrating normal to nearly normal tissue. Gobbi and colleagues⁵⁵ also found evidence for superiority of chondral defects treated with BMAC compared to matrix-induced autologous chondrocyte implantation (MACI) for patellofemoral lesions in 37 patients (MRI showed complete filling of defects in 81% of BMAC-treated patients vs 76% of MACI-treated patients).

Meniscal Repair

Clinical application of MSCs in the treatment of meniscal pathology is evolving as well. ASCs have been added to modify the biomechanical environment of avascular zone meniscal tears at the time of suture repair in a rabbit, and have demonstrated increased healing rates in small and larger lesions, although the effect lessens with delay in repair.⁶³ Angele and colleagues⁶⁴ treated meniscal defects in a rabbit model with scaffolds with bm-MSCs compared with empty scaffolds or control cohorts and found a higher proportion of menisci with healed meniscus-like fibrocartilage when MSCs were utilized.

In humans, Vangsness and colleagues³⁰ treated knees with partial medial meniscectomy with allogeneic stem cells and reported an increase in meniscal volume and decrease in pain in those patients when compared to a cohort of knees treated with hyaluronic acid. Despite promising early results, additional clinical studies are necessary to determine the external validity and broad applicability of stem cell use in meniscal repair.

Rotator Cuff Repair

The number of local resident stem cells at the site of rotator cuff tear has been shown to decrease with tear size, chronicity, and degree of fatty infiltration, suggesting that those with the greatest need for a good reparative environment are those least equipped to heal.⁶⁵ The need for improvement in this domain is related to the still relatively high re-tear rate after rotator cuff repair despite improvements in instrumentation and surgical technique.⁶⁶ The native fibrocartilaginous transition zone between the humerus and the rotator cuff becomes a fibrovascular scar tissue after rupture and repair with poorer material properties than the native tissue.⁶⁷ Thus, a-MSCs have been evaluated in this setting to determine if the biomechanical and histological properties of the repair may improve.⁶⁸

In rat models, Valencia Mora and colleagues⁶⁸ reported on the application of a-MSCs in a rat rotator cuff repair model compared to an untreated group. They found no differences between those treated rats and those without a-MSCs use in terms of biomechanical properties of the tendon-to-bone healing, but those with stem cell use had less inflammation shown histologically (diminished presence of edema and neutrophils) at 2- and 4-week time points, which the authors suggested may lead to a more elastic repair and less scar at the bone-tendon healing site. Oh and colleagues¹ evaluated the use of a-MSCs in a rabbit subscapularis tear model, and reported significantly reduced fatty infiltration at the site of chronic rotator cuff tear after repair with its application at the repair site; while the load-to-failure was higher in those rabbits with ASCs administration, it was short of reaching statistical significance. Yokoya and colleagues⁶⁹ demonstrated regeneration of rotator cuff tendon-to-bone insertional site anatomy and in the belly of the cuff tendon in a rabbit model with MSCs applied at the operative site. However, Gulotta and colleagues⁷⁰ did not see the same improvement in their similar study in the rat model; these authors failed to see improvement in structure, strength, or composition of the tendinous attachment site despite addition of MSCs.

Clinical studies on augmented rotator cuff repair have also found mixed results. MSCs for this purpose have been cultivated from arthroscopic bone marrow aspiration of the proximal humerus⁷¹ and subacromial bursa⁷² with successful and reproducibly high concentrations of stem cells. Hernigou and colleagues⁷³ found a significant improvement in rate of healing (87% intact cuffs vs 44% in the control group) and repair surface tendon integrity (via ultrasound and MRI) for patients at a minimum of 10 years after rotator cuff repair with MSC injection at the time of surgery. The authors found a direct correlation in these outcomes with the number of MSCs injected at the time of repair. Ellera Gomes and colleagues⁷⁴ injected bm-MSCs obtained from the iliac crest into the tendinous repair site in 14 consecutive patients with full-thickness rotator cuff tears treated by transosseous sutures via a mini-open approach. MRI demonstrated integrity of the repair site in all patients at more than 1-year follow-up.

Achilles Tendon Repair

The goal with stem cell use in Achilles repair is to accelerate the healing and rehabilitation. Several animal studies have demonstrated improved mechanical properties and collagen composition of tendon repairs augmented with stem cells, including Achilles tendon repair in a rat model. Adams and colleagues⁷⁵ compared suture alone (36 tendons) to suture plus stem cell concentrate injection (36 tendons) and stem cell loaded suture (36 tendons) in Achilles tendon repair with rat models. The suture-alone cohort had lower ultimate failure loads at 14 days after surgery, indicating biomechanical superiority with stem cell augmentation means. Transplantation of hypoxic MSCs at the time of Achilles tendon repair may be a promising option for superior biomechanical failure loads and histologic findings as per recent rat model findings by Huang and colleagues.⁷⁶ Yao and colleagues⁷⁷ demonstrated increased strength of suture repair for Achilles repair in rat models at early time points when using MSC-coated suture in comparison to standard suture, and suggested that the addition of stem cells may improve early mechanical properties during the tendon repair process. A-MSC addition to PRP has provided significantly increased tensile strength to rabbit models with Achilles tendon repair as well.⁷⁸

In evaluation of stem cell use for this purpose with humans, Stein and colleagues⁷⁹ reviewed 28 sports-related Achilles tendon ruptures in 27 patients treated with open repair and BMAC injection. At a mean follow-up of 29.7 months, the authors reported no re-ruptures, with 92% return to sport at 5.9 months, and excellent clinical outcomes. This small cohort study found no adverse outcomes related to the BMAC addition, and thus proposed further study of the efficacy of stem cell treatment for Achilles tendon repair.

Anterior Cruciate Ligament Reconstruction

Bm-MSCs genetically modified with bone morphogenetic protein 2 (BMP2) and basic fibroblast growth factor (bFGF) have shown great promise in improvement of the formation of mechanically sound tendon-bone interface in anterior cruciate ligament (ACL) reconstruction.⁸⁰ Similar to the other surgical procedures mentioned in this review, animal studies have successfully evaluated the augmentation of osteointegration of tendon to bone in the setting of ACL reconstruction. Jang and colleagues³ investigated the use of nonautologous transplantation of human umbilical cord blood-derived MSCs in a rabbit ACL reconstruction model. The authors demonstrated a lack of immune rejection, and enhanced tendon-bone healing with broad fibrocartilage formation at the transition zone (similar to the native ACL) and decreased femoral and tibial tunnel widening as compared to a control cohort at 12-weeks after surgery. In a rat model, Kanaya and colleagues⁸¹ reported improved histological scores and slight improvements in biomechanical integrity of partially transected rat ACLs treated with intra-articular MSC injection. Stem cell use in the form of suture-supporting scaffolds seeded with MSCs has been evaluated in a total ACL transection rabbit model; the authors of this report demonstrated total ACL regeneration in one-third of samples treated with this augmentation option, in comparison to complete failure in all suture and scaffold alone groups.⁸²

The use of autologous MSCs in ACL healing remains limited to preclinical research and small case series of patients. One human trial by Silva and colleagues⁸³ evaluated the graft-to-bone site of healing in ACL reconstruction for 20 patients who received an intraoperative infiltration of their graft with adult bm-MSCs. MRI and histologic analysis showed no difference in comparison to control groups, but the authors’ conclusion proposed that the number of stem cells injected might have been too minimal to show a clinical effect.

Other Applications

Although outside the scope of this article, stem cells have demonstrated efficacy in the treatment of a number of osseous clinical entities. This includes the treatment of fracture nonunion, augmentation of spinal fusion, and assistance in the treatment of osteonecrosis.⁸⁴

Summary

As a scientific community, our understanding of the use of stem cells, their nuances, and their indications has expanded dramatically over the last several years. Stem cell treatment has particularly infiltrated the world of operative and nonoperative sports medicine, given in part the active patient population seeking greater levels of improvement.⁸⁵ Stem cell therapy offers a potentially effective therapy for a multitude of pathologies because of these cells’ anti-inflammatory, immunoregulatory, angiogenic, and paracrine effects.⁸⁶ It thus remains a very dynamic option in the study of musculoskeletal tissue regeneration. While the potential exists for stem cell use in daily surgery practices, it is still premature to predict whether this can be expected.

The ideal stem cell sources (including allogeneic or autologous), preparation, cell number, timing, and means of application continue to be evaluated, as well as those advantageous pathologies that can benefit from the technology. In order to better answer these pertinent questions, we need to make sure we have a safe, economic, and ethically acceptable means for stem cell translational research efforts. More high-level studies with standardized protocols need to be performed. It is necessary to improve national and international collaboration in research, as well as collaboration with governing bodies, to attempt to further scientific advancement in this field of research.⁴⁹ Further study on embryonic stem cell use may be valuable as well, pending governmental approval. Finally, more dedicated research efforts must be placed on the utility of adjuncts with stem cell use, including PRP and scaffolds, which may increase protection, nutritional support, and mechanical stimulation of the administered stem cells.

Biologic use in orthopedics is a continuously evolving field that complements technical, anatomic, and biomechanical advancements in orthopedics. Biologic agents are receiving increasing attention for their use in augmenting healing of muscles, tendons, ligaments, and osseous structures. As biologic augmentation strategies become increasingly utilized in bony and soft-tissue injuries, research on stem cell use in orthopedics continues to increase. Stem cell-based therapies for the repair or regeneration of muscle and tendon represent a promising technology going forward for numerous diseases.¹

Stem cells by definition are undifferentiated cells that have 4 main characteristics: (1) mobilization during angiogenesis, (2) differentiation into specialized cell types, (3) proliferation and regeneration, and (4) release of immune regulators and growth factors.² Mesenchymal stem cells (MSCs) have garnered the most attention in the field of surgery due to their ability to differentiate into the tissues of interest for the surgeon.³ This includes both bone marrow-derived mesenchymal stem cells (bm-MSCs) and adipose-derived mesenchymal stem cells (a-MSCs). These multipotent stem cells in adults originate from mesenchymal tissues, including bone marrow, tendon, adipose, and muscle tissue.⁴ They are attractive for clinical use because of their multipotent potential and relative ease of growth in culture.⁵ They also exert a paracrine effect to modulate and control inflammation, stimulate endogenous cell repair and proliferation, inhibit apoptosis, and improve blood flow through secretion of chemokines, cytokines, and growth factors.^6,7

Questions exist regarding the best way to administer stem cells, whether systematic administration is possible for these cells to localize to the tissue in need, or more likely if direct application to the pathologic area is necessary.^8,9 A number of sources, purification process, and modes of delivery are available, but the most effective means of preparation and administration are still under investigation. The goal of this review is to illustrate the current state of knowledge surrounding stem cell therapy in orthopedics with a focus on osteoarthritis, tendinopathy, articular cartilage, and enhancement of surgical procedures.

Important Considerations

Common stem cell isolates include embryonic, induced pluripotent, and mesenchymal formulations (Table 1). MSCs can be obtained from multiple sites, including but not limited to the adult bone marrow, adipose, muscular, or tendinous tissues, and their use has been highlighted in the study of numerous orthopedic and nonorthopedic pathologies over the course of the last decade. Research on the use of embryonic stem cells in medical therapy with human implications has received substantial attention, with many ethical concerns by those opposed, and the existence of a potential risk of malignant alterations.^8,10 Amniotic-derived stem cells can be isolated from amniotic fluid, umbilical cord blood, or the placenta and thus do not harbor the same social constraints as the aforementioned embryonic cells; however, they do not harbor the same magnitude of multi-differentiation potential, either.⁴

Adult MSCs are more locally available and easy to obtain for treatment when compared with embryonic and fetal stem cells, and the former has a lower immunogenicity, which allows allogeneic use.¹¹ Safety has been preliminarily demonstrated in use thus far; Centeno and colleagues¹² found no neoplastic tissue generation at the site of stem cell injection after 3 years postinjection for a cohort of patients who were treated with autologous bm-MSCs for various pathologies. Self-limited pain and swelling are the most commonly reported adverse events after use.¹³ However, long-term data are lacking in many instances to definitively suggest the absence of possible complications.

Basic Science

Stem cell research encompasses a wide range of rapidly developing treatment strategies that are applicable to virtually every field of medicine. In general, stem cells can be classified as embryonic stem cells (ESCs), induced pluripotent stem (iPS) cells, or adult-derived MSCs. ESCs are embryonic cells derived typically from fetal tissue, whereas iPS cells are dedifferentiated from adult tissue, thus avoiding many of the ethical and legal challenges imposed by research with ESCs. However, oncogenic and lingering politico-legal concerns with introducing dedifferentiated ESCs or iPS cells into healthy tissue necessitate the development, isolation, and expansion of multi- but not pluripotent stem cell lines.¹⁴ To date, the most advantageous and widely utilized from any perspective are MSCs, which can further differentiate into cartilage, tendon, muscle, and bony tissue.^7,15,16

MSCs are defined by their ability to demonstrate in vitro differentiation into osteoblasts, adipocytes, or chondroblasts, adhere to plastic, express CD105, CD73, and CD90, and not express CD43, CD23, CD14 or CD11b, CD79 or CD19, or HLA-DR.¹⁷ Porada and Almeida-Porada¹⁸ have outlined 6 reasons highlighting the advantages of MSCs: 1) ease of isolation, 2) high differentiation capabilities, 3) strong colony expansion without differentiation loss, 4) immunosuppression following transplantation, 5) powerful anti-inflammatory properties, and 6) their ability to localize to damaged tissue. The anti-inflammatory properties of MSCs are particularly important as they promote allo- and xenotransplantation from donor tissues.^19,20 MSCs can be isolated from numerous sources, including but not limited to bone marrow, periosteum, adipocyte, and muscle.^21-23 Interestingly, the source tissue used to isolate MSCs can affect differentiation capabilities, colony size, and growth rate (Table 2).²⁴ Advantages of a-MSCs include high prevalence and ease of harvest; however, several animal studies have shown inferior results when compared to bm-MSCs.^25-27 More research is needed to determine the ideal source material for MSCs, which will likely depend in part on the procedure for which they are employed.²⁷

Following harvesting, isolation, and expansion, MSC delivery methods for treatments typically consist of either cell-based or tissue engineering approaches. Cell-based techniques involve the injection of MSCs into damaged tissues. Purely cell-based therapy has shown success in limited clinical trials involving knee osteoarthritis, cartilage repair, and meniscal repair.^28-30 However, additional studies with longer follow-up are required to validate these preliminary findings. Tissue engineering approaches involve the construction of a 3-dimensional scaffold seeded with MSCs that is later surgically implanted. While promising in theory, limited and often conflicting data exist regarding the efficacy of tissue-engineered MSC implantation.^31-32 Suboptimal scaffold vascularity is a major limitation to scaffold design, which may be alleviated in part with the advent of 3-dimensional printing and the ability to more precisely alter scaffold architecture.^14,33 Additional limitations include ensuring MSC purity and differentiation potential following harvesting and expansion. At present, the use of tissue engineering with MSCs is promising but it remains a nascent technology with additional preclinical studies required to confirm implant efficacy and safety.

Clinical Entities

Osteoarthritis

MSC therapies have emerged as promising treatment strategies in the setting of early osteoarthritis (OA). In addition to their regenerative potential, MSCs demonstrate potent anti-inflammatory properties, increasing their attractiveness as biologic agents in the setting of OA.³⁴ Over the past decade, multiple human trials have been published demonstrating the efficacy of MSC injections into patients with OA.^35,36 In a study evaluating a-MSC injection into elderly patients (age >65 years) with knee OA, Koh and colleagues²⁹ found that 88% demonstrated improved cartilage status at 2-year follow-up, while no patient underwent a total knee arthroplasty during this time period. In another study investigating patients with unicompartmental knee OA with varus alignment undergoing high tibial osteotomy and microfracture, Wong and colleagues³⁷ reported improved clinical, patient-reported, and magnetic resonance imaging (MRI)-based outcomes in a group receiving a preoperative MSC injection compared to a control group. Further, in a recent randomized control trial of patients with knee osteoarthritis, Vega and colleagues³⁸ reported improved cartilage and quality of life outcomes at 1 year following MSC injection compared to a control group receiving a hyaluronic acid injection. In addition to knee OA, studies have also reported improvement in ankle OA following MSC injection.³⁹ While promising, many of the preliminary clinical studies evaluating the efficacy of MSC therapies in the treatment of OA are hindered by small patient populations and short-term follow-up. Additional large-scale, randomized studies are required and many are ongoing presently in hopes of validating these preliminary findings.³⁶

Tendinopathy

The quality of repaired tissue in primary tendon-to-tendon and tendon-to-bone healing has long been a topic of great interest.⁴⁰ The healing potential of tendons is inferior to that of other bony and connective tissues,⁴¹ with tendon healing typically resulting in a biomechanically and histologically inferior structure to the native tissue.⁴² As such, this has been a particularly salient opportunity for stem cell use with hopes of recapitulating a more normal tendon or tendon enthesis following injury. In addition to the acute injury, there is great interest in the application of stem cells to chronic states of injury such as tendinopathy.

In equine models, the effect of autologous bm-MSCs treatment on tendinopathy of the superficial digital flexor tendon has been studied. Godwin and colleagues⁴³ evaluated 141 race horses with spontaneous superficial digital flexor tendinopathy treated in this manner, and reported a reinjury percentage in these treated horses of just 27.4%, which compared favorably to historical controls and alternative therapeutics. Machova Urdzikova and colleagues⁴⁴ injected MSCs at Achilles tendinopathy locations to augment nonoperative healing in 40 rats, and identified more native histological organization and improved vascularization in comparison to control rat specimens. Oshita and colleagues⁴⁵ reported histologic improvement of tendinopathy findings in 8 rats receiving a-MSCs at the location of induced Achilles tendinopathy that was significantly superior to a control cohort. Bm-MSCs were used by Yuksel and colleagues⁴⁶ in comparison with platelet-rich plasma (PRP) for treatment of Achilles tendon ruptures created surgically in rat models. They demonstrated successful effects with its use in terms of recovery for the tendon’s histopathologic, immunohistochemical, and biomechanical properties, related to significantly greater levels of anti-inflammatory cytokines. However, these aforementioned findings have not been uniform across the literature—other authors have reported findings that MSC transplantation alone did not repair Achilles tendon injury with such high levels of success.⁴⁷

Human treatment of tendinopathies with stem cells has been scarcely studied to date. Pascual-Garrido and colleagues⁴⁸ evaluated 8 patients with refractory patellar tendinopathy treated with injection of autologous bm-MSCs and reported successful results at 2- to 5-year follow-up, with significant improvements in patient-reported outcome measures for 100% of patients. Seven of 8 (87.5%) noted that they would undergo the procedure again.

Articular Cartilage Injury

Chondral injury is a particularly important subject given the limited potential of chondrocytes to replicate or migrate to the site of pathology.⁴⁹ Stem cell use in this setting assists with programmed growth factor release and alteration of the anatomic microenvironment to facilitate regeneration and repair of the chondral surface. Autologous stem cell use through microfracture provides a perforation into the bone marrow and a subsequent fibrin clot formation containing platelets, growth factors, vascular elements, and MSCs.⁵⁰ A similar concept to PRP is currently being explored with bm-MSCs. Isolated bm-MSCs are commonly referred to as bone marrow aspirate or bone marrow aspirate concentrate (BMAC). Commercially available systems are now available to aid in the harvesting and implementation of BMAC. One of the more promising avenues for BMAC implementation is in articular cartilage repair or regeneration due to chondrogenic potential of BMAC when used in isolation or when combined with microfracture, chondrocyte transfer, or collagen scaffolds.^19,51 Synovial-derived stem cells as an additional source for stem cell use has demonstrated excellent chondrogenic potential in animal studies with full-thickness lesion healing and native-appearing cartilage histologically.⁵² Incorporation of a-MSCs into scaffolds for surgical implantation has demonstrated success in repairing full-thickness chondral defects with continuous joint surface and extracellular proteins, surface markers, and gene products similar to the native cartilage in animal models.^53,54 In light of the promising basic science and animal studies, clinical studies have begun to emerge.^55-57

Fortier and colleagues⁵⁸ found MRI and histologic evidence of full-thickness chondral repair and increased integration with neighboring cartilage when BMAC was concurrently used at the time of microfracture in an equine model. Fortier and colleagues⁵⁸ also demonstrated greater healing in equine models with acute full-thickness cartilage defects treated by microfracture with MSCs than without delivery of MSCs. Kim and colleagues^59,60 similarly reported superiority in clinical outcomes for patients with osteochondral lesions of the talus treated with marrow stimulation and MSC injection than by the former in isolation.

In humans, stem cell use for chondral repair has additionally proven promising. A systematic review of the literature suggested good to excellent overall outcomes for the treatment of moderate focal chondral defects with BMAC with or without scaffolds and microfracture with inclusion of 8 total publications.⁶¹ This review included Gobbi and colleagues,⁶² who prospectively treated 15 patients with a mean focal chondral defect size of 9.2 cm² about the knee. Use of BMAC covered with a collagen I/III matrix produced significant improvements in patient-reported outcome scores and MRI demonstrated complete hyaline-like cartilage coverage in 80%, with second-look arthroscopy demonstrating normal to nearly normal tissue. Gobbi and colleagues⁵⁵ also found evidence for superiority of chondral defects treated with BMAC compared to matrix-induced autologous chondrocyte implantation (MACI) for patellofemoral lesions in 37 patients (MRI showed complete filling of defects in 81% of BMAC-treated patients vs 76% of MACI-treated patients).

Meniscal Repair

Clinical application of MSCs in the treatment of meniscal pathology is evolving as well. ASCs have been added to modify the biomechanical environment of avascular zone meniscal tears at the time of suture repair in a rabbit, and have demonstrated increased healing rates in small and larger lesions, although the effect lessens with delay in repair.⁶³ Angele and colleagues⁶⁴ treated meniscal defects in a rabbit model with scaffolds with bm-MSCs compared with empty scaffolds or control cohorts and found a higher proportion of menisci with healed meniscus-like fibrocartilage when MSCs were utilized.

In humans, Vangsness and colleagues³⁰ treated knees with partial medial meniscectomy with allogeneic stem cells and reported an increase in meniscal volume and decrease in pain in those patients when compared to a cohort of knees treated with hyaluronic acid. Despite promising early results, additional clinical studies are necessary to determine the external validity and broad applicability of stem cell use in meniscal repair.

Rotator Cuff Repair

The number of local resident stem cells at the site of rotator cuff tear has been shown to decrease with tear size, chronicity, and degree of fatty infiltration, suggesting that those with the greatest need for a good reparative environment are those least equipped to heal.⁶⁵ The need for improvement in this domain is related to the still relatively high re-tear rate after rotator cuff repair despite improvements in instrumentation and surgical technique.⁶⁶ The native fibrocartilaginous transition zone between the humerus and the rotator cuff becomes a fibrovascular scar tissue after rupture and repair with poorer material properties than the native tissue.⁶⁷ Thus, a-MSCs have been evaluated in this setting to determine if the biomechanical and histological properties of the repair may improve.⁶⁸

In rat models, Valencia Mora and colleagues⁶⁸ reported on the application of a-MSCs in a rat rotator cuff repair model compared to an untreated group. They found no differences between those treated rats and those without a-MSCs use in terms of biomechanical properties of the tendon-to-bone healing, but those with stem cell use had less inflammation shown histologically (diminished presence of edema and neutrophils) at 2- and 4-week time points, which the authors suggested may lead to a more elastic repair and less scar at the bone-tendon healing site. Oh and colleagues¹ evaluated the use of a-MSCs in a rabbit subscapularis tear model, and reported significantly reduced fatty infiltration at the site of chronic rotator cuff tear after repair with its application at the repair site; while the load-to-failure was higher in those rabbits with ASCs administration, it was short of reaching statistical significance. Yokoya and colleagues⁶⁹ demonstrated regeneration of rotator cuff tendon-to-bone insertional site anatomy and in the belly of the cuff tendon in a rabbit model with MSCs applied at the operative site. However, Gulotta and colleagues⁷⁰ did not see the same improvement in their similar study in the rat model; these authors failed to see improvement in structure, strength, or composition of the tendinous attachment site despite addition of MSCs.

Clinical studies on augmented rotator cuff repair have also found mixed results. MSCs for this purpose have been cultivated from arthroscopic bone marrow aspiration of the proximal humerus⁷¹ and subacromial bursa⁷² with successful and reproducibly high concentrations of stem cells. Hernigou and colleagues⁷³ found a significant improvement in rate of healing (87% intact cuffs vs 44% in the control group) and repair surface tendon integrity (via ultrasound and MRI) for patients at a minimum of 10 years after rotator cuff repair with MSC injection at the time of surgery. The authors found a direct correlation in these outcomes with the number of MSCs injected at the time of repair. Ellera Gomes and colleagues⁷⁴ injected bm-MSCs obtained from the iliac crest into the tendinous repair site in 14 consecutive patients with full-thickness rotator cuff tears treated by transosseous sutures via a mini-open approach. MRI demonstrated integrity of the repair site in all patients at more than 1-year follow-up.

Achilles Tendon Repair

The goal with stem cell use in Achilles repair is to accelerate the healing and rehabilitation. Several animal studies have demonstrated improved mechanical properties and collagen composition of tendon repairs augmented with stem cells, including Achilles tendon repair in a rat model. Adams and colleagues⁷⁵ compared suture alone (36 tendons) to suture plus stem cell concentrate injection (36 tendons) and stem cell loaded suture (36 tendons) in Achilles tendon repair with rat models. The suture-alone cohort had lower ultimate failure loads at 14 days after surgery, indicating biomechanical superiority with stem cell augmentation means. Transplantation of hypoxic MSCs at the time of Achilles tendon repair may be a promising option for superior biomechanical failure loads and histologic findings as per recent rat model findings by Huang and colleagues.⁷⁶ Yao and colleagues⁷⁷ demonstrated increased strength of suture repair for Achilles repair in rat models at early time points when using MSC-coated suture in comparison to standard suture, and suggested that the addition of stem cells may improve early mechanical properties during the tendon repair process. A-MSC addition to PRP has provided significantly increased tensile strength to rabbit models with Achilles tendon repair as well.⁷⁸

In evaluation of stem cell use for this purpose with humans, Stein and colleagues⁷⁹ reviewed 28 sports-related Achilles tendon ruptures in 27 patients treated with open repair and BMAC injection. At a mean follow-up of 29.7 months, the authors reported no re-ruptures, with 92% return to sport at 5.9 months, and excellent clinical outcomes. This small cohort study found no adverse outcomes related to the BMAC addition, and thus proposed further study of the efficacy of stem cell treatment for Achilles tendon repair.

Anterior Cruciate Ligament Reconstruction

Bm-MSCs genetically modified with bone morphogenetic protein 2 (BMP2) and basic fibroblast growth factor (bFGF) have shown great promise in improvement of the formation of mechanically sound tendon-bone interface in anterior cruciate ligament (ACL) reconstruction.⁸⁰ Similar to the other surgical procedures mentioned in this review, animal studies have successfully evaluated the augmentation of osteointegration of tendon to bone in the setting of ACL reconstruction. Jang and colleagues³ investigated the use of nonautologous transplantation of human umbilical cord blood-derived MSCs in a rabbit ACL reconstruction model. The authors demonstrated a lack of immune rejection, and enhanced tendon-bone healing with broad fibrocartilage formation at the transition zone (similar to the native ACL) and decreased femoral and tibial tunnel widening as compared to a control cohort at 12-weeks after surgery. In a rat model, Kanaya and colleagues⁸¹ reported improved histological scores and slight improvements in biomechanical integrity of partially transected rat ACLs treated with intra-articular MSC injection. Stem cell use in the form of suture-supporting scaffolds seeded with MSCs has been evaluated in a total ACL transection rabbit model; the authors of this report demonstrated total ACL regeneration in one-third of samples treated with this augmentation option, in comparison to complete failure in all suture and scaffold alone groups.⁸²

The use of autologous MSCs in ACL healing remains limited to preclinical research and small case series of patients. One human trial by Silva and colleagues⁸³ evaluated the graft-to-bone site of healing in ACL reconstruction for 20 patients who received an intraoperative infiltration of their graft with adult bm-MSCs. MRI and histologic analysis showed no difference in comparison to control groups, but the authors’ conclusion proposed that the number of stem cells injected might have been too minimal to show a clinical effect.

Other Applications

Although outside the scope of this article, stem cells have demonstrated efficacy in the treatment of a number of osseous clinical entities. This includes the treatment of fracture nonunion, augmentation of spinal fusion, and assistance in the treatment of osteonecrosis.⁸⁴

Summary

As a scientific community, our understanding of the use of stem cells, their nuances, and their indications has expanded dramatically over the last several years. Stem cell treatment has particularly infiltrated the world of operative and nonoperative sports medicine, given in part the active patient population seeking greater levels of improvement.⁸⁵ Stem cell therapy offers a potentially effective therapy for a multitude of pathologies because of these cells’ anti-inflammatory, immunoregulatory, angiogenic, and paracrine effects.⁸⁶ It thus remains a very dynamic option in the study of musculoskeletal tissue regeneration. While the potential exists for stem cell use in daily surgery practices, it is still premature to predict whether this can be expected.

The ideal stem cell sources (including allogeneic or autologous), preparation, cell number, timing, and means of application continue to be evaluated, as well as those advantageous pathologies that can benefit from the technology. In order to better answer these pertinent questions, we need to make sure we have a safe, economic, and ethically acceptable means for stem cell translational research efforts. More high-level studies with standardized protocols need to be performed. It is necessary to improve national and international collaboration in research, as well as collaboration with governing bodies, to attempt to further scientific advancement in this field of research.⁴⁹ Further study on embryonic stem cell use may be valuable as well, pending governmental approval. Finally, more dedicated research efforts must be placed on the utility of adjuncts with stem cell use, including PRP and scaffolds, which may increase protection, nutritional support, and mechanical stimulation of the administered stem cells.

A new index can be used to predict which women will experience faster bone loss while transitioning to menopause, according to a study in the Journal of Clinical Endocrinology & Metabolism.

To create the new index, called the Bone Balance Index, researchers used data from a cohort of 685 women ages 42 to 52 as they went through menopause. The women were either premenopausal or in early perimenopause when they enrolled in the study, and all participants had their final menstrual period during follow-up.

Urine and blood samples were taken from the women to measure bone turnover markers. The women also had their bone mineral density measured every year.

The investigators combined measurements of bone breakdown and bone formation to determine each woman’s net bone balance before their final menstrual period. The study authors found that compared to a measurement of bone breakdown alone, the Bone Balance Index was a stronger predictor of bone loss from 2 years before the final menstrual period to 3 to 4 years later.

A new index can be used to predict which women will experience faster bone loss while transitioning to menopause, according to a study in the Journal of Clinical Endocrinology & Metabolism.

To create the new index, called the Bone Balance Index, researchers used data from a cohort of 685 women ages 42 to 52 as they went through menopause. The women were either premenopausal or in early perimenopause when they enrolled in the study, and all participants had their final menstrual period during follow-up.

Urine and blood samples were taken from the women to measure bone turnover markers. The women also had their bone mineral density measured every year.

The investigators combined measurements of bone breakdown and bone formation to determine each woman’s net bone balance before their final menstrual period. The study authors found that compared to a measurement of bone breakdown alone, the Bone Balance Index was a stronger predictor of bone loss from 2 years before the final menstrual period to 3 to 4 years later.

A new index can be used to predict which women will experience faster bone loss while transitioning to menopause, according to a study in the Journal of Clinical Endocrinology & Metabolism.

To create the new index, called the Bone Balance Index, researchers used data from a cohort of 685 women ages 42 to 52 as they went through menopause. The women were either premenopausal or in early perimenopause when they enrolled in the study, and all participants had their final menstrual period during follow-up.

Urine and blood samples were taken from the women to measure bone turnover markers. The women also had their bone mineral density measured every year.

The investigators combined measurements of bone breakdown and bone formation to determine each woman’s net bone balance before their final menstrual period. The study authors found that compared to a measurement of bone breakdown alone, the Bone Balance Index was a stronger predictor of bone loss from 2 years before the final menstrual period to 3 to 4 years later.

A substantial percentage of patients who receive opioid medications before undergoing arthroplasty continue to take them up to 6 months after surgery, according to a study published in Pain.

Researchers analyzed opioid use in 574 patients who underwent arthroplasty. Patients were followed up at 1, 3, and 6 months after surgery to assess rates of long-term opioid use and risk factors for long-term opioid use. About 30% of patients were taking opioids prior to their joint replacement surgery. Of this group, 53% of knee-replacement patients and 35% of hip replacement patients continued taking opioids 6 months after surgery.

Patients who were not taking opioids prior to surgery were less likely to report persistent opioid use. About 8% in the knee replacement group and 4% in the hip replacement group were still taking opioids at the 6-month follow-up. Patients who were taking the highest doses of opioids before surgery were most likely to continue to take them for 6 months.

Among patients not previously taking opioids, those with higher pain scores the day of surgery were more likely to report persistent opioid use at 6 months. However, improvement in knee or hip pain after arthroplasty did not reduce the likelihood of long-term opioid use.

A substantial percentage of patients who receive opioid medications before undergoing arthroplasty continue to take them up to 6 months after surgery, according to a study published in Pain.

Researchers analyzed opioid use in 574 patients who underwent arthroplasty. Patients were followed up at 1, 3, and 6 months after surgery to assess rates of long-term opioid use and risk factors for long-term opioid use. About 30% of patients were taking opioids prior to their joint replacement surgery. Of this group, 53% of knee-replacement patients and 35% of hip replacement patients continued taking opioids 6 months after surgery.

Patients who were not taking opioids prior to surgery were less likely to report persistent opioid use. About 8% in the knee replacement group and 4% in the hip replacement group were still taking opioids at the 6-month follow-up. Patients who were taking the highest doses of opioids before surgery were most likely to continue to take them for 6 months.

Among patients not previously taking opioids, those with higher pain scores the day of surgery were more likely to report persistent opioid use at 6 months. However, improvement in knee or hip pain after arthroplasty did not reduce the likelihood of long-term opioid use.

A substantial percentage of patients who receive opioid medications before undergoing arthroplasty continue to take them up to 6 months after surgery, according to a study published in Pain.

Researchers analyzed opioid use in 574 patients who underwent arthroplasty. Patients were followed up at 1, 3, and 6 months after surgery to assess rates of long-term opioid use and risk factors for long-term opioid use. About 30% of patients were taking opioids prior to their joint replacement surgery. Of this group, 53% of knee-replacement patients and 35% of hip replacement patients continued taking opioids 6 months after surgery.

Patients who were not taking opioids prior to surgery were less likely to report persistent opioid use. About 8% in the knee replacement group and 4% in the hip replacement group were still taking opioids at the 6-month follow-up. Patients who were taking the highest doses of opioids before surgery were most likely to continue to take them for 6 months.

Among patients not previously taking opioids, those with higher pain scores the day of surgery were more likely to report persistent opioid use at 6 months. However, improvement in knee or hip pain after arthroplasty did not reduce the likelihood of long-term opioid use.

The American Academy of Orthopedic Surgeons has introduced apps that orthopedic surgeons can use to explain musculoskeletal problems and procedures to their patients. The Guides to Orthopedic Surgery cover total knee replacement, total hip replacement, and ACL reconstruction. These apps can be loaded onto exam room desktops or used on an iPad.

The apps also provide ways to create custom educational information for patients, and may be set up with certain electronic medical records to support Meaningful Use requirements. A free trial of the apps is available until June 30. More information: www.aaosnotice.org/Ortho_App/.

The American Academy of Orthopedic Surgeons has introduced apps that orthopedic surgeons can use to explain musculoskeletal problems and procedures to their patients. The Guides to Orthopedic Surgery cover total knee replacement, total hip replacement, and ACL reconstruction. These apps can be loaded onto exam room desktops or used on an iPad.

The apps also provide ways to create custom educational information for patients, and may be set up with certain electronic medical records to support Meaningful Use requirements. A free trial of the apps is available until June 30. More information: www.aaosnotice.org/Ortho_App/.

The American Academy of Orthopedic Surgeons has introduced apps that orthopedic surgeons can use to explain musculoskeletal problems and procedures to their patients. The Guides to Orthopedic Surgery cover total knee replacement, total hip replacement, and ACL reconstruction. These apps can be loaded onto exam room desktops or used on an iPad.

The apps also provide ways to create custom educational information for patients, and may be set up with certain electronic medical records to support Meaningful Use requirements. A free trial of the apps is available until June 30. More information: www.aaosnotice.org/Ortho_App/.

Reverse total shoulder arthroplasty (RTSA) has become a reliable treatment option for many pathologic conditions of the shoulder, including rotator cuff arthropathy, proximal humerus fractures, and others.^1-4 While the treatment outcomes have generally been reported as good, some concern exists over the postoperative range of motion (ROM) in patients following RTSA, including external rotation.^5-7 The original RTSA design was introduced by Neer in the 1970s and has undergone many modifications since that time.^1,2 The original Grammont-style prosthesis involved medialization of the glenoid, inferiorizing the center of rotation (with increased deltoid tensioning), and a neck-shaft angle of 155°.^1,8 While clinical results of the 155° design were encouraging, concerns arose over the significance of the common finding of scapular notching, or contact between the scapular neck and inferior portion of the humeral polyethylene when the arm is adducted.^9,10

To address this concern, a prosthesis design with a 135° neck-shaft angle was introduced.¹¹ This new design did significantly decrease the rate of scapular notching, and although some reported a concern over implant stability with the 135° prosthesis, recent data has shown no difference in dislocation rates between the 135° and 155° prostheses.³ A different variable that has not been evaluated between these prostheses is the active ROM that is achieved postoperatively, and the change in ROM from pre- to post-RTSA.^12,13 As active ROM plays a significant role in shoulder function and patient satisfaction, the question of whether a significant difference exists in postoperative ROM between the 135° and 155° prostheses must be addressed.

The purpose of this study was to perform a systematic review investigating active ROM following RTSA to determine if active postoperative ROM following RTSA differs between the 135° and 155° humeral inclination prostheses, and to determine if there is a significant difference between the change in preoperative and postoperative ROM between the 135° and 155° prostheses. The authors hypothesize that there will be no significant difference in active postoperative ROM between the 135° and 155° prostheses, and that the difference between preoperative and postoperative ROM (that is, the amount of motion gained by the surgery) will not significantly differ between the 135° and 155° prostheses.

Methods

A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using a PRISMA checklist.¹⁵ Systematic review registration was performed using the PROSPERO international prospective register of systematic reviews (registration date 3/9/15, registration number CRD42015017367).¹⁶ Two reviewers independently conducted the search on March 7, 2015 using the following databases: Medline, Cochrane Central Register of Controlled Trials, SportDiscus, and CINAHL. The electronic search citation algorithm utilized was: (((((reverse[Title/Abstract]) AND shoulder[Title/Abstract]) AND arthroplasty[Title/Abstract]) NOT arthroscopic[Title/Abstract]) NOT cadaver[Title/Abstract]) NOT biomechanical[Title/Abstract]. English language Level I-IV evidence (2011 update by the Oxford Centre for Evidence-Based Medicine¹⁷) clinical studies that reported the type of RTSA prosthesis that was used as well as postoperative ROM with at least 12 months follow-up were eligible. All references within included studies were cross-referenced for inclusion if missed by the initial search. If duplicate subject publications were discovered, the study with the longer duration of follow-up or larger number of patients was included. Level V evidence reviews, letters to the editor, basic science, biomechanical studies, arthroscopic shoulder surgery, imaging, surgical technique, and classification studies were excluded. Studies were excluded if both a 135° and 155° prosthesis were utilized and the outcomes were not stratified by the humeral inclination. Studies that did not report ROM were excluded.

A total of 456 studies were located, and, after implementation of the exclusion criteria, 65 studies from 2005-2015 were included in the final analysis (Figure). Subjects of interest in this systematic review underwent a RTSA. Studies were not excluded based on the surgical indications (rotator cuff tear arthropathy, proximal humerus fractures, osteoarthritis) and there was no minimum follow-up or rehabilitation requirement. Study and subject demographic parameters analyzed included year of publication, journal of publication, country and continent of publication, years of subject enrollment, presence of study financial conflict of interest, number of subjects and shoulders, gender, age, the manufacturer and type of prosthesis used, and the degree of the humeral inclination (135° vs 155° humeral cup). Preoperative ROM, including forward elevation, abduction, external rotation with the arm adducted, and external rotation with the arm at 90° of abduction, were recorded. The same ROM measurements were recorded for the final follow-up visit that was reported. Internal rotation was recorded, but because of the variability with how this measurement was reported, it was not analyzed. Clinical outcome scores and complications were not assessed. Study methodological quality was evaluated using the Modified Coleman Methodology Score (MCMS).¹⁸

Statistical Analysis

Descriptive statistics were calculated, including mean ± standard deviation for quantitative continuous data and frequencies with percentages for qualitative categorical data. ROM comparisons between 135° and 155° components (pre- vs postoperative for each and postoperative between the 2) were made using 2 proportion z-test calculator (http://in-silico.net/tools/statistics/ztest) using alpha .05 because of the difference in sample sizes between compared groups.

Results

Sixty-five studies with 3302 patients (3434 shoulders) were included in this study. There was a total of 1211 shoulders in the 135° lateralized glenosphere group and 2223 shoulders in the 155° group. The studies had an average MCMS of 40.4 ± 8.2 (poor), 48% of studies reported a conflict of interest, 32% had no conflict of interest, and 20% did not report whether a conflict of interest existed or not. The majority of studies included were level IV evidence (85%). Mean patient age was 71.1 ± 7.6 years; 29% of patients were male and 71% were female. No significant difference existed between patient age at the time of surgery; the average age of patients in the 135° lateralized glenosphere group was 71.67 ± 3.8 years, while the average patient age of patients in the 155° group was 70.97 ± 8.8 years. Mean follow-up for all patients included in this study was 37.2 ± 16.5 months. Of the 65 studies included, 3 were published from Asia, 4 were published from Australia, 24 were from North America, and 34 were from Europe. Of the individual countries whose studies were included, the United States had 23 included studies, France had 13 included studies, and Italy had 4 included studies. All other countries had <4 studies included.

Patients who received either a 135° or a 155° prosthesis showed significant improvements in external rotation with the arm at the side (P < .05), forward elevation (P < .05), and abduction (P < .05) following surgery (Table). When comparing the 135° and 155° groups, patients who received a 135° prosthesis showed significantly greater improvements in external rotation with the arm at the side (P < .001) and had significantly more overall external rotation postoperatively (P < .001) than patients who received a 155° prosthesis. The only preoperative ROM difference between groups was the 155° group started with significantly more forward elevation than the 135°group prior to surgery (P = .002).

Discussion

RTSA is indicated in patients with rotator cuff tear arthropathy, pseudoparalysis, and a functional deltoid.^1,2,4 The purpose of this systematic review was to determine if active ROM following RTSA differs between the 135° and 155° humeral inclination prostheses, and to determine if there is a significant difference between the change in preoperative and postoperative ROM between the 135° and 155° prostheses. Forward elevation, abduction, and external rotation all significantly improved following surgery in both groups, with no significant difference between groups in motion or amount of motion improvement, mostly confirming the study hypotheses. However, patients in the 135° group had significantly greater postoperative external rotation and greater amount of external rotation improvement compared to the 155° group.

Two of the frequently debated issues regarding implant geometry is stability and scapular notching between the 135° and 155° humeral inclination designs. Erickson and colleagues3 recently evaluated the rate of scapular notching and dislocations between the 135° and 155° RTSA prostheses. The authors found that the 135° prosthesis had a significantly lower incidence of scapular notching vs the 155° group and that the rate of dislocations was not significantly different between groups.³ In the latter systematic review, the authors attempted to evaluate ROM between the 135° and 155° prostheses, but as the inclusion criteria of the study was reporting on scapular notching and dislocation rates, many studies reporting solely on ROM were excluded, and the influence of humeral inclination on ROM was inconclusive.³ Furthermore, there have been no studies that have directly compared ROM following RTSA between the 135° and 155° prostheses. While studies evaluating each prosthesis on an individual level have shown an improvement in ROM from pre- to postsurgery, there have been no large studies that have compared the postoperative ROM and change in pre- to postoperative ROM between the 135° and 155° prostheses.^11,13,19,20

One study by Valenti and colleagues²¹ evaluated a group of 30 patients with an average age of 69.5 years who underwent RTSA using either a 135° or a 155° prosthesis. Although the study did not directly compare the 2 types of prostheses, it did report the separate outcomes for each prosthesis. At an average follow-up of 36.4 months, the authors found that patients who had the 135° prosthesis implanted had a mean increase in forward elevation and external rotation of 53° and 9°, while patients who had the 155° showed an increase of 56° in forward elevation and a loss of 1° of external rotation. Both prostheses showed a significant increase in forward elevation, but neither had a significant increase in external rotation. Furthermore, scapular notching was seen in 4 patients in the 155° group, while no patients in the 135° group had evidence of notching.

The results of the current study were similar in that both the 135° and 155° prosthesis showed improvements in forward elevation following surgery, and the 135° group showed a significantly greater gain in external rotation than the 155° group. A significant component of shoulder function and patient satisfaction following RTSA is active ROM. However, this variable has not explicitly been evaluated in the literature until now. The clinical significance of this finding is unclear. Patients with adequate external rotation prior to surgery likely would not see a functional difference between prostheses, while those patients who were borderline on a functional amount of external rotation would see a clinically significant benefit with the 135° prosthesis. Studies have shown that the 135° prosthesis is more anatomic than the 155°, and this could explain the difference seen in ROM outcomes between the 2 prostheses.¹⁹ Ladermann and colleagues²² recently created and evaluated a 3-dimensional computer model to evaluate possible differences between the 135° and 155° prosthesis. The authors found a significant increase in external rotation of the 135° compared to the 155°, likely related to a difference in acromiohumeral distance as well as inlay vs onlay humeral trays between the 2 prostheses. The results of this study parallel the computer model, thereby validating these experimental results.

It is important to understand what the minimum functional ROM of the shoulder is (in other words, the ROM necessary to complete activities of daily living (ADLs).²³ Namdari and colleagues²⁴ used motion analysis software to evaluate the shoulder ROM necessary to complete 10 different ADLs, including combing hair, washing the back of the opposite shoulder, and reaching a shelf above their head without bending their elbow in 20 patients with a mean age of 29.2 years. They found that patients required 121° ± 6.7° of flexion, 46° ± 5.3° of extension, 128° ± 7.9° of abduction, 116° ± 9.1° of cross-body adduction, 59° ± 10° of external rotation with the arm 90° abducted, and 102° ± 7.7° of internal rotation with the arm at the side (external rotation with the arm at the side was not well defined).²⁴ Hence, while abduction and forward elevation seem comparable, the results from the current study do raise concerns about the amount of external rotation obtained following RTSA as it relates to a patients’ ability to perform ADLs, specifically in the 155° prosthesis, as the average postoperative external rotation in this group was 20.5°. Therefore, based on the results of this study, it appears that, while both the 135° and 155° RTSA prostheses provide similar gain in forward elevation and abduction ROM as well as overall forward elevation and abduction, the 135° prosthesis provides significantly more external rotation with the arm at the side than the 155° prosthesis.

Limitations

Although this study attempted to look at all studies that reported active ROM in patients following a RTSA, and 2 authors performed the search, there is a possibility that some studies were missed, introducing study selection bias. Furthermore, the mean follow-up was over 3 years following surgery, but the minimum follow-up requirement for studies to be included was only 12 months. Hence, this transfer bias introduces the possibility that the patient’s ROM would have changed had they been followed for a standard period of time. There are many variables that come into play in evaluating ROM, and although the study attempted to control for these, there are some that could not be controlled for due to lack of reporting by some studies. Glenosphere size and humeral retroversion were not recorded, as they were not reliably reported in all studies, so motion outcomes based on these variables was not evaluated. Complications and clinical outcomes were not assessed in this review and as such, conclusions regarding these variables cannot be drawn from this study. Finally, indications for surgery were not reliably reported in the studies included in this paper, so differences may have existed between surgical indications of the 135° and 155° groups that could have affected outcomes.

Conclusion

Patients who receive a 135° RTSA gain significantly more external rotation from pre- to postsurgery and have an overall greater amount of external rotation than patients who receive a 155° prosthesis. Both groups show improvements in forward elevation, external rotation, and abduction following surgery.

Reverse total shoulder arthroplasty (RTSA) has become a reliable treatment option for many pathologic conditions of the shoulder, including rotator cuff arthropathy, proximal humerus fractures, and others.^1-4 While the treatment outcomes have generally been reported as good, some concern exists over the postoperative range of motion (ROM) in patients following RTSA, including external rotation.^5-7 The original RTSA design was introduced by Neer in the 1970s and has undergone many modifications since that time.^1,2 The original Grammont-style prosthesis involved medialization of the glenoid, inferiorizing the center of rotation (with increased deltoid tensioning), and a neck-shaft angle of 155°.^1,8 While clinical results of the 155° design were encouraging, concerns arose over the significance of the common finding of scapular notching, or contact between the scapular neck and inferior portion of the humeral polyethylene when the arm is adducted.^9,10

To address this concern, a prosthesis design with a 135° neck-shaft angle was introduced.¹¹ This new design did significantly decrease the rate of scapular notching, and although some reported a concern over implant stability with the 135° prosthesis, recent data has shown no difference in dislocation rates between the 135° and 155° prostheses.³ A different variable that has not been evaluated between these prostheses is the active ROM that is achieved postoperatively, and the change in ROM from pre- to post-RTSA.^12,13 As active ROM plays a significant role in shoulder function and patient satisfaction, the question of whether a significant difference exists in postoperative ROM between the 135° and 155° prostheses must be addressed.

The purpose of this study was to perform a systematic review investigating active ROM following RTSA to determine if active postoperative ROM following RTSA differs between the 135° and 155° humeral inclination prostheses, and to determine if there is a significant difference between the change in preoperative and postoperative ROM between the 135° and 155° prostheses. The authors hypothesize that there will be no significant difference in active postoperative ROM between the 135° and 155° prostheses, and that the difference between preoperative and postoperative ROM (that is, the amount of motion gained by the surgery) will not significantly differ between the 135° and 155° prostheses.

Methods

A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using a PRISMA checklist.¹⁵ Systematic review registration was performed using the PROSPERO international prospective register of systematic reviews (registration date 3/9/15, registration number CRD42015017367).¹⁶ Two reviewers independently conducted the search on March 7, 2015 using the following databases: Medline, Cochrane Central Register of Controlled Trials, SportDiscus, and CINAHL. The electronic search citation algorithm utilized was: (((((reverse[Title/Abstract]) AND shoulder[Title/Abstract]) AND arthroplasty[Title/Abstract]) NOT arthroscopic[Title/Abstract]) NOT cadaver[Title/Abstract]) NOT biomechanical[Title/Abstract]. English language Level I-IV evidence (2011 update by the Oxford Centre for Evidence-Based Medicine¹⁷) clinical studies that reported the type of RTSA prosthesis that was used as well as postoperative ROM with at least 12 months follow-up were eligible. All references within included studies were cross-referenced for inclusion if missed by the initial search. If duplicate subject publications were discovered, the study with the longer duration of follow-up or larger number of patients was included. Level V evidence reviews, letters to the editor, basic science, biomechanical studies, arthroscopic shoulder surgery, imaging, surgical technique, and classification studies were excluded. Studies were excluded if both a 135° and 155° prosthesis were utilized and the outcomes were not stratified by the humeral inclination. Studies that did not report ROM were excluded.

A total of 456 studies were located, and, after implementation of the exclusion criteria, 65 studies from 2005-2015 were included in the final analysis (Figure). Subjects of interest in this systematic review underwent a RTSA. Studies were not excluded based on the surgical indications (rotator cuff tear arthropathy, proximal humerus fractures, osteoarthritis) and there was no minimum follow-up or rehabilitation requirement. Study and subject demographic parameters analyzed included year of publication, journal of publication, country and continent of publication, years of subject enrollment, presence of study financial conflict of interest, number of subjects and shoulders, gender, age, the manufacturer and type of prosthesis used, and the degree of the humeral inclination (135° vs 155° humeral cup). Preoperative ROM, including forward elevation, abduction, external rotation with the arm adducted, and external rotation with the arm at 90° of abduction, were recorded. The same ROM measurements were recorded for the final follow-up visit that was reported. Internal rotation was recorded, but because of the variability with how this measurement was reported, it was not analyzed. Clinical outcome scores and complications were not assessed. Study methodological quality was evaluated using the Modified Coleman Methodology Score (MCMS).¹⁸

Statistical Analysis

Descriptive statistics were calculated, including mean ± standard deviation for quantitative continuous data and frequencies with percentages for qualitative categorical data. ROM comparisons between 135° and 155° components (pre- vs postoperative for each and postoperative between the 2) were made using 2 proportion z-test calculator (http://in-silico.net/tools/statistics/ztest) using alpha .05 because of the difference in sample sizes between compared groups.

Results

Sixty-five studies with 3302 patients (3434 shoulders) were included in this study. There was a total of 1211 shoulders in the 135° lateralized glenosphere group and 2223 shoulders in the 155° group. The studies had an average MCMS of 40.4 ± 8.2 (poor), 48% of studies reported a conflict of interest, 32% had no conflict of interest, and 20% did not report whether a conflict of interest existed or not. The majority of studies included were level IV evidence (85%). Mean patient age was 71.1 ± 7.6 years; 29% of patients were male and 71% were female. No significant difference existed between patient age at the time of surgery; the average age of patients in the 135° lateralized glenosphere group was 71.67 ± 3.8 years, while the average patient age of patients in the 155° group was 70.97 ± 8.8 years. Mean follow-up for all patients included in this study was 37.2 ± 16.5 months. Of the 65 studies included, 3 were published from Asia, 4 were published from Australia, 24 were from North America, and 34 were from Europe. Of the individual countries whose studies were included, the United States had 23 included studies, France had 13 included studies, and Italy had 4 included studies. All other countries had <4 studies included.

Patients who received either a 135° or a 155° prosthesis showed significant improvements in external rotation with the arm at the side (P < .05), forward elevation (P < .05), and abduction (P < .05) following surgery (Table). When comparing the 135° and 155° groups, patients who received a 135° prosthesis showed significantly greater improvements in external rotation with the arm at the side (P < .001) and had significantly more overall external rotation postoperatively (P < .001) than patients who received a 155° prosthesis. The only preoperative ROM difference between groups was the 155° group started with significantly more forward elevation than the 135°group prior to surgery (P = .002).

Discussion

RTSA is indicated in patients with rotator cuff tear arthropathy, pseudoparalysis, and a functional deltoid.^1,2,4 The purpose of this systematic review was to determine if active ROM following RTSA differs between the 135° and 155° humeral inclination prostheses, and to determine if there is a significant difference between the change in preoperative and postoperative ROM between the 135° and 155° prostheses. Forward elevation, abduction, and external rotation all significantly improved following surgery in both groups, with no significant difference between groups in motion or amount of motion improvement, mostly confirming the study hypotheses. However, patients in the 135° group had significantly greater postoperative external rotation and greater amount of external rotation improvement compared to the 155° group.

Two of the frequently debated issues regarding implant geometry is stability and scapular notching between the 135° and 155° humeral inclination designs. Erickson and colleagues3 recently evaluated the rate of scapular notching and dislocations between the 135° and 155° RTSA prostheses. The authors found that the 135° prosthesis had a significantly lower incidence of scapular notching vs the 155° group and that the rate of dislocations was not significantly different between groups.³ In the latter systematic review, the authors attempted to evaluate ROM between the 135° and 155° prostheses, but as the inclusion criteria of the study was reporting on scapular notching and dislocation rates, many studies reporting solely on ROM were excluded, and the influence of humeral inclination on ROM was inconclusive.³ Furthermore, there have been no studies that have directly compared ROM following RTSA between the 135° and 155° prostheses. While studies evaluating each prosthesis on an individual level have shown an improvement in ROM from pre- to postsurgery, there have been no large studies that have compared the postoperative ROM and change in pre- to postoperative ROM between the 135° and 155° prostheses.^11,13,19,20

One study by Valenti and colleagues²¹ evaluated a group of 30 patients with an average age of 69.5 years who underwent RTSA using either a 135° or a 155° prosthesis. Although the study did not directly compare the 2 types of prostheses, it did report the separate outcomes for each prosthesis. At an average follow-up of 36.4 months, the authors found that patients who had the 135° prosthesis implanted had a mean increase in forward elevation and external rotation of 53° and 9°, while patients who had the 155° showed an increase of 56° in forward elevation and a loss of 1° of external rotation. Both prostheses showed a significant increase in forward elevation, but neither had a significant increase in external rotation. Furthermore, scapular notching was seen in 4 patients in the 155° group, while no patients in the 135° group had evidence of notching.

The results of the current study were similar in that both the 135° and 155° prosthesis showed improvements in forward elevation following surgery, and the 135° group showed a significantly greater gain in external rotation than the 155° group. A significant component of shoulder function and patient satisfaction following RTSA is active ROM. However, this variable has not explicitly been evaluated in the literature until now. The clinical significance of this finding is unclear. Patients with adequate external rotation prior to surgery likely would not see a functional difference between prostheses, while those patients who were borderline on a functional amount of external rotation would see a clinically significant benefit with the 135° prosthesis. Studies have shown that the 135° prosthesis is more anatomic than the 155°, and this could explain the difference seen in ROM outcomes between the 2 prostheses.¹⁹ Ladermann and colleagues²² recently created and evaluated a 3-dimensional computer model to evaluate possible differences between the 135° and 155° prosthesis. The authors found a significant increase in external rotation of the 135° compared to the 155°, likely related to a difference in acromiohumeral distance as well as inlay vs onlay humeral trays between the 2 prostheses. The results of this study parallel the computer model, thereby validating these experimental results.

It is important to understand what the minimum functional ROM of the shoulder is (in other words, the ROM necessary to complete activities of daily living (ADLs).²³ Namdari and colleagues²⁴ used motion analysis software to evaluate the shoulder ROM necessary to complete 10 different ADLs, including combing hair, washing the back of the opposite shoulder, and reaching a shelf above their head without bending their elbow in 20 patients with a mean age of 29.2 years. They found that patients required 121° ± 6.7° of flexion, 46° ± 5.3° of extension, 128° ± 7.9° of abduction, 116° ± 9.1° of cross-body adduction, 59° ± 10° of external rotation with the arm 90° abducted, and 102° ± 7.7° of internal rotation with the arm at the side (external rotation with the arm at the side was not well defined).²⁴ Hence, while abduction and forward elevation seem comparable, the results from the current study do raise concerns about the amount of external rotation obtained following RTSA as it relates to a patients’ ability to perform ADLs, specifically in the 155° prosthesis, as the average postoperative external rotation in this group was 20.5°. Therefore, based on the results of this study, it appears that, while both the 135° and 155° RTSA prostheses provide similar gain in forward elevation and abduction ROM as well as overall forward elevation and abduction, the 135° prosthesis provides significantly more external rotation with the arm at the side than the 155° prosthesis.

Limitations

Although this study attempted to look at all studies that reported active ROM in patients following a RTSA, and 2 authors performed the search, there is a possibility that some studies were missed, introducing study selection bias. Furthermore, the mean follow-up was over 3 years following surgery, but the minimum follow-up requirement for studies to be included was only 12 months. Hence, this transfer bias introduces the possibility that the patient’s ROM would have changed had they been followed for a standard period of time. There are many variables that come into play in evaluating ROM, and although the study attempted to control for these, there are some that could not be controlled for due to lack of reporting by some studies. Glenosphere size and humeral retroversion were not recorded, as they were not reliably reported in all studies, so motion outcomes based on these variables was not evaluated. Complications and clinical outcomes were not assessed in this review and as such, conclusions regarding these variables cannot be drawn from this study. Finally, indications for surgery were not reliably reported in the studies included in this paper, so differences may have existed between surgical indications of the 135° and 155° groups that could have affected outcomes.

Conclusion

Patients who receive a 135° RTSA gain significantly more external rotation from pre- to postsurgery and have an overall greater amount of external rotation than patients who receive a 155° prosthesis. Both groups show improvements in forward elevation, external rotation, and abduction following surgery.

Reverse total shoulder arthroplasty (RTSA) has become a reliable treatment option for many pathologic conditions of the shoulder, including rotator cuff arthropathy, proximal humerus fractures, and others.^1-4 While the treatment outcomes have generally been reported as good, some concern exists over the postoperative range of motion (ROM) in patients following RTSA, including external rotation.^5-7 The original RTSA design was introduced by Neer in the 1970s and has undergone many modifications since that time.^1,2 The original Grammont-style prosthesis involved medialization of the glenoid, inferiorizing the center of rotation (with increased deltoid tensioning), and a neck-shaft angle of 155°.^1,8 While clinical results of the 155° design were encouraging, concerns arose over the significance of the common finding of scapular notching, or contact between the scapular neck and inferior portion of the humeral polyethylene when the arm is adducted.^9,10

To address this concern, a prosthesis design with a 135° neck-shaft angle was introduced.¹¹ This new design did significantly decrease the rate of scapular notching, and although some reported a concern over implant stability with the 135° prosthesis, recent data has shown no difference in dislocation rates between the 135° and 155° prostheses.³ A different variable that has not been evaluated between these prostheses is the active ROM that is achieved postoperatively, and the change in ROM from pre- to post-RTSA.^12,13 As active ROM plays a significant role in shoulder function and patient satisfaction, the question of whether a significant difference exists in postoperative ROM between the 135° and 155° prostheses must be addressed.

The purpose of this study was to perform a systematic review investigating active ROM following RTSA to determine if active postoperative ROM following RTSA differs between the 135° and 155° humeral inclination prostheses, and to determine if there is a significant difference between the change in preoperative and postoperative ROM between the 135° and 155° prostheses. The authors hypothesize that there will be no significant difference in active postoperative ROM between the 135° and 155° prostheses, and that the difference between preoperative and postoperative ROM (that is, the amount of motion gained by the surgery) will not significantly differ between the 135° and 155° prostheses.

Methods

A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using a PRISMA checklist.¹⁵ Systematic review registration was performed using the PROSPERO international prospective register of systematic reviews (registration date 3/9/15, registration number CRD42015017367).¹⁶ Two reviewers independently conducted the search on March 7, 2015 using the following databases: Medline, Cochrane Central Register of Controlled Trials, SportDiscus, and CINAHL. The electronic search citation algorithm utilized was: (((((reverse[Title/Abstract]) AND shoulder[Title/Abstract]) AND arthroplasty[Title/Abstract]) NOT arthroscopic[Title/Abstract]) NOT cadaver[Title/Abstract]) NOT biomechanical[Title/Abstract]. English language Level I-IV evidence (2011 update by the Oxford Centre for Evidence-Based Medicine¹⁷) clinical studies that reported the type of RTSA prosthesis that was used as well as postoperative ROM with at least 12 months follow-up were eligible. All references within included studies were cross-referenced for inclusion if missed by the initial search. If duplicate subject publications were discovered, the study with the longer duration of follow-up or larger number of patients was included. Level V evidence reviews, letters to the editor, basic science, biomechanical studies, arthroscopic shoulder surgery, imaging, surgical technique, and classification studies were excluded. Studies were excluded if both a 135° and 155° prosthesis were utilized and the outcomes were not stratified by the humeral inclination. Studies that did not report ROM were excluded.

A total of 456 studies were located, and, after implementation of the exclusion criteria, 65 studies from 2005-2015 were included in the final analysis (Figure). Subjects of interest in this systematic review underwent a RTSA. Studies were not excluded based on the surgical indications (rotator cuff tear arthropathy, proximal humerus fractures, osteoarthritis) and there was no minimum follow-up or rehabilitation requirement. Study and subject demographic parameters analyzed included year of publication, journal of publication, country and continent of publication, years of subject enrollment, presence of study financial conflict of interest, number of subjects and shoulders, gender, age, the manufacturer and type of prosthesis used, and the degree of the humeral inclination (135° vs 155° humeral cup). Preoperative ROM, including forward elevation, abduction, external rotation with the arm adducted, and external rotation with the arm at 90° of abduction, were recorded. The same ROM measurements were recorded for the final follow-up visit that was reported. Internal rotation was recorded, but because of the variability with how this measurement was reported, it was not analyzed. Clinical outcome scores and complications were not assessed. Study methodological quality was evaluated using the Modified Coleman Methodology Score (MCMS).¹⁸

Statistical Analysis

Descriptive statistics were calculated, including mean ± standard deviation for quantitative continuous data and frequencies with percentages for qualitative categorical data. ROM comparisons between 135° and 155° components (pre- vs postoperative for each and postoperative between the 2) were made using 2 proportion z-test calculator (http://in-silico.net/tools/statistics/ztest) using alpha .05 because of the difference in sample sizes between compared groups.

Results

Sixty-five studies with 3302 patients (3434 shoulders) were included in this study. There was a total of 1211 shoulders in the 135° lateralized glenosphere group and 2223 shoulders in the 155° group. The studies had an average MCMS of 40.4 ± 8.2 (poor), 48% of studies reported a conflict of interest, 32% had no conflict of interest, and 20% did not report whether a conflict of interest existed or not. The majority of studies included were level IV evidence (85%). Mean patient age was 71.1 ± 7.6 years; 29% of patients were male and 71% were female. No significant difference existed between patient age at the time of surgery; the average age of patients in the 135° lateralized glenosphere group was 71.67 ± 3.8 years, while the average patient age of patients in the 155° group was 70.97 ± 8.8 years. Mean follow-up for all patients included in this study was 37.2 ± 16.5 months. Of the 65 studies included, 3 were published from Asia, 4 were published from Australia, 24 were from North America, and 34 were from Europe. Of the individual countries whose studies were included, the United States had 23 included studies, France had 13 included studies, and Italy had 4 included studies. All other countries had <4 studies included.

Patients who received either a 135° or a 155° prosthesis showed significant improvements in external rotation with the arm at the side (P < .05), forward elevation (P < .05), and abduction (P < .05) following surgery (Table). When comparing the 135° and 155° groups, patients who received a 135° prosthesis showed significantly greater improvements in external rotation with the arm at the side (P < .001) and had significantly more overall external rotation postoperatively (P < .001) than patients who received a 155° prosthesis. The only preoperative ROM difference between groups was the 155° group started with significantly more forward elevation than the 135°group prior to surgery (P = .002).

Discussion

RTSA is indicated in patients with rotator cuff tear arthropathy, pseudoparalysis, and a functional deltoid.^1,2,4 The purpose of this systematic review was to determine if active ROM following RTSA differs between the 135° and 155° humeral inclination prostheses, and to determine if there is a significant difference between the change in preoperative and postoperative ROM between the 135° and 155° prostheses. Forward elevation, abduction, and external rotation all significantly improved following surgery in both groups, with no significant difference between groups in motion or amount of motion improvement, mostly confirming the study hypotheses. However, patients in the 135° group had significantly greater postoperative external rotation and greater amount of external rotation improvement compared to the 155° group.

Two of the frequently debated issues regarding implant geometry is stability and scapular notching between the 135° and 155° humeral inclination designs. Erickson and colleagues3 recently evaluated the rate of scapular notching and dislocations between the 135° and 155° RTSA prostheses. The authors found that the 135° prosthesis had a significantly lower incidence of scapular notching vs the 155° group and that the rate of dislocations was not significantly different between groups.³ In the latter systematic review, the authors attempted to evaluate ROM between the 135° and 155° prostheses, but as the inclusion criteria of the study was reporting on scapular notching and dislocation rates, many studies reporting solely on ROM were excluded, and the influence of humeral inclination on ROM was inconclusive.³ Furthermore, there have been no studies that have directly compared ROM following RTSA between the 135° and 155° prostheses. While studies evaluating each prosthesis on an individual level have shown an improvement in ROM from pre- to postsurgery, there have been no large studies that have compared the postoperative ROM and change in pre- to postoperative ROM between the 135° and 155° prostheses.^11,13,19,20

One study by Valenti and colleagues²¹ evaluated a group of 30 patients with an average age of 69.5 years who underwent RTSA using either a 135° or a 155° prosthesis. Although the study did not directly compare the 2 types of prostheses, it did report the separate outcomes for each prosthesis. At an average follow-up of 36.4 months, the authors found that patients who had the 135° prosthesis implanted had a mean increase in forward elevation and external rotation of 53° and 9°, while patients who had the 155° showed an increase of 56° in forward elevation and a loss of 1° of external rotation. Both prostheses showed a significant increase in forward elevation, but neither had a significant increase in external rotation. Furthermore, scapular notching was seen in 4 patients in the 155° group, while no patients in the 135° group had evidence of notching.

The results of the current study were similar in that both the 135° and 155° prosthesis showed improvements in forward elevation following surgery, and the 135° group showed a significantly greater gain in external rotation than the 155° group. A significant component of shoulder function and patient satisfaction following RTSA is active ROM. However, this variable has not explicitly been evaluated in the literature until now. The clinical significance of this finding is unclear. Patients with adequate external rotation prior to surgery likely would not see a functional difference between prostheses, while those patients who were borderline on a functional amount of external rotation would see a clinically significant benefit with the 135° prosthesis. Studies have shown that the 135° prosthesis is more anatomic than the 155°, and this could explain the difference seen in ROM outcomes between the 2 prostheses.¹⁹ Ladermann and colleagues²² recently created and evaluated a 3-dimensional computer model to evaluate possible differences between the 135° and 155° prosthesis. The authors found a significant increase in external rotation of the 135° compared to the 155°, likely related to a difference in acromiohumeral distance as well as inlay vs onlay humeral trays between the 2 prostheses. The results of this study parallel the computer model, thereby validating these experimental results.

It is important to understand what the minimum functional ROM of the shoulder is (in other words, the ROM necessary to complete activities of daily living (ADLs).²³ Namdari and colleagues²⁴ used motion analysis software to evaluate the shoulder ROM necessary to complete 10 different ADLs, including combing hair, washing the back of the opposite shoulder, and reaching a shelf above their head without bending their elbow in 20 patients with a mean age of 29.2 years. They found that patients required 121° ± 6.7° of flexion, 46° ± 5.3° of extension, 128° ± 7.9° of abduction, 116° ± 9.1° of cross-body adduction, 59° ± 10° of external rotation with the arm 90° abducted, and 102° ± 7.7° of internal rotation with the arm at the side (external rotation with the arm at the side was not well defined).²⁴ Hence, while abduction and forward elevation seem comparable, the results from the current study do raise concerns about the amount of external rotation obtained following RTSA as it relates to a patients’ ability to perform ADLs, specifically in the 155° prosthesis, as the average postoperative external rotation in this group was 20.5°. Therefore, based on the results of this study, it appears that, while both the 135° and 155° RTSA prostheses provide similar gain in forward elevation and abduction ROM as well as overall forward elevation and abduction, the 135° prosthesis provides significantly more external rotation with the arm at the side than the 155° prosthesis.

Limitations

Although this study attempted to look at all studies that reported active ROM in patients following a RTSA, and 2 authors performed the search, there is a possibility that some studies were missed, introducing study selection bias. Furthermore, the mean follow-up was over 3 years following surgery, but the minimum follow-up requirement for studies to be included was only 12 months. Hence, this transfer bias introduces the possibility that the patient’s ROM would have changed had they been followed for a standard period of time. There are many variables that come into play in evaluating ROM, and although the study attempted to control for these, there are some that could not be controlled for due to lack of reporting by some studies. Glenosphere size and humeral retroversion were not recorded, as they were not reliably reported in all studies, so motion outcomes based on these variables was not evaluated. Complications and clinical outcomes were not assessed in this review and as such, conclusions regarding these variables cannot be drawn from this study. Finally, indications for surgery were not reliably reported in the studies included in this paper, so differences may have existed between surgical indications of the 135° and 155° groups that could have affected outcomes.

Conclusion

Patients who receive a 135° RTSA gain significantly more external rotation from pre- to postsurgery and have an overall greater amount of external rotation than patients who receive a 155° prosthesis. Both groups show improvements in forward elevation, external rotation, and abduction following surgery.

Developing a high-efficiency operating room (OR) is both a challenging and rewarding goal for any healthcare system. The OR is traditionally a high-cost/high-revenue environment¹ and operative efficacy has been correlated with low complication rates and surgical success.² An efficient OR is one that maximizes utilization while providing safe, reproducible, cost-effective, high-quality care. Total joint arthroplasty (TJA) has occupied the center stage for OR efficiency research, in part due to increasing demands from our aging population³ and economic pressures related to high implant costs, decreased reimbursement, and competition for market shares when OR time and space are limited.

A PubMed search on OR efficiency in TJA shows a disproportionately high focus on surgical technique, such as use of patient-specific instrumentation (PSI), computer-assisted surgery (CAS), minimally invasive surgery, and closure with barbed suture. In a retrospective review of 352 TKA patients who had PSI vs conventional instrumentation, DeHaan and colleagues⁴ found that PSI was associated with significantly decreased operative and room turnover times (20.4 minutes and 6.4 minutes, respectively). In another prospective multicenter study, Mont and colleagues⁵ showed a reduction in surgical time by 8.90 min for navigated total knee arthroplasty (TKA) performed with single-use instruments, cutting blocks, and trials. Other investigators compared PSI to CAS in TKA and found PSI to be 1.45 times more profitable than CAS, with 3 PSI cases performed in an 8-hour OR day compared to 2 CAS cases.⁶

There is no question that improved surgical technique can enhance OR efficiency. However, this model, while promising, is difficult to implement on a wide scale due to surgeon preferences, vendor limitations, and added costs related to the advanced preoperative imaging studies, manufacturing of the custom guides, and maintenance of navigation equipment. In addition, while interventions such as the use of barbed suture have the potential for speeding closure time, the time saved (4.7 minutes in one randomized trial)⁷ may not be enough to affect major utilization differences per OR per day. These technologies are also frequently employed by high-volume surgeons with high-volume teams and institutions.

Ideally, we need investment in the human capital and a collective change in work cultures to produce high-quality, well-choreographed, easily reproducible routines. An efficient OR requires the synchronous involvement of a large team of individuals, including hospital administrators, surgery schedulers, surgeons, anesthesiologists, preoperative holding area staff, OR nurses, surgical attendants, sterile processing personnel, and recovery room nurses. Case schedulers should match allocated block time with time required for surgery based on the historical performance of the individual surgeon, preferably scheduling similar cases on the same day. Preoperative work-up and medical clearance should be completed prior to scheduling to avoid last-minute cancellations. Patient reminders and accommodations for those traveling from long distances can further minimize late arrivals. Prompt initiation of the perioperative clinical pathway upon a patient’s check-in is important. The surgical site should be marked and the anesthesia plan confirmed upon arrival in the preoperative holding area. Necessary products need to be ready and/or administrated in time for transfer to the OR. These include prophylactic antibiotics, coagulation factors (eg, tranexamic acid), and blood products as indicated. Spinal anesthesia, regional nerve blocks, and intravenous (IV) lines should be completed before transfer to the OR. A “block room” close to the OR can allow concurrent induction of anesthesia and has been shown to increase the number of surgical cases performed during a regular workday.⁸ Hair clipping within the surgical site and pre-scrubbing of the operative extremity should also be performed prior to transfer to the OR in order to minimize micro-organisms and dispersal of loose hair onto the sterile field.

Upon arrival of the patient to the OR, instrument tables based on the surgeon preference cards should be opened, instrument count and implant templating completed, necessary imaging displayed, and OR staff ready with specific responsibilities assigned to each member. Small and colleagues⁹ showed that using dedicated orthopedic staff familiar with the surgical routine decreased operative time by 19 minutes per procedure, or 1.25 hours for a surgeon performing 4 primary TJAs per day. Practices such as routine placement of a urinary catheter should be seriously scrutinized. In a randomized prospective study of patients undergoing total hip arthroplasty under spinal anesthesia, Miller and colleagues¹⁰ found no benefit for indwelling catheters in preventing urinary retention. In another randomized prospective study, Huang and colleagues¹¹ found the prevalence of urinary tract infections was significantly higher in TJA patients who received indwelling urinary catheters.

A scrub nurse familiar with the instruments, their assembly, and the sequence of events can ensure efficient surgical flow. The scrub nurse needs to anticipate missing or defective tools and call for them, ideally before the incision is made. Direct comparison studies are needed to assess the efficacy of routine intraoperative imaging vs commercially available universal cup alignment guides or clinical examinations in determining acceptable component positioning and limb length. Following component implantation and before wound closure, the circulating nurse should initiate the process of acquisition of a recovery room bed, make sure dressing supplies and necessary equipment are available, and call for surgical attendants. Lack of surgical attendants, delayed transfer from the OR table to hospital bed, and prolonged acquisition of a recovery room bed have been identified as major OR inefficiencies in a retrospective study by Attarian and colleagues.¹²

In summary, time is the OR’s most valuable resource.¹³ We believe that a consistent, almost automated attitude to the above procedures decreases variability and improves efficiency. By providing clear communication of the surgical needs with the team, having consistent anesthesia and nursing staff, implementing consistent perioperative protocols, and insuring that all necessary instruments and modalities are available prior to starting the procedure, we were able to sustainably increase OR throughput in a large teaching hospital.^9,14 This process, however, requires constant review to identify and eliminate new gaps, with each member of the team sharing a frank desire to improve. In this regard, hospital administrators share the duty to facilitate the implementation of any necessary changes, allocation of needed resources, and rewarding good effort, which could ultimately increase staff satisfaction and retention. Because efficiency is the ratio of benefits (eg, revenue, safety, etc.) to investment (eg, implant costs, wages, etc.), raises the question: what would be the effect of transitioning from hourly-wage to a salary-based system for key support staff? Unlike hourly-wage personnel, who have no incentive for productivity, a salaried employee assigned to a high-efficiency OR will inherently strive for improvement, employing higher organizational skills to accomplish a common goal. To our knowledge, there is no published data on this topic.

Developing a high-efficiency operating room (OR) is both a challenging and rewarding goal for any healthcare system. The OR is traditionally a high-cost/high-revenue environment¹ and operative efficacy has been correlated with low complication rates and surgical success.² An efficient OR is one that maximizes utilization while providing safe, reproducible, cost-effective, high-quality care. Total joint arthroplasty (TJA) has occupied the center stage for OR efficiency research, in part due to increasing demands from our aging population³ and economic pressures related to high implant costs, decreased reimbursement, and competition for market shares when OR time and space are limited.

A PubMed search on OR efficiency in TJA shows a disproportionately high focus on surgical technique, such as use of patient-specific instrumentation (PSI), computer-assisted surgery (CAS), minimally invasive surgery, and closure with barbed suture. In a retrospective review of 352 TKA patients who had PSI vs conventional instrumentation, DeHaan and colleagues⁴ found that PSI was associated with significantly decreased operative and room turnover times (20.4 minutes and 6.4 minutes, respectively). In another prospective multicenter study, Mont and colleagues⁵ showed a reduction in surgical time by 8.90 min for navigated total knee arthroplasty (TKA) performed with single-use instruments, cutting blocks, and trials. Other investigators compared PSI to CAS in TKA and found PSI to be 1.45 times more profitable than CAS, with 3 PSI cases performed in an 8-hour OR day compared to 2 CAS cases.⁶

There is no question that improved surgical technique can enhance OR efficiency. However, this model, while promising, is difficult to implement on a wide scale due to surgeon preferences, vendor limitations, and added costs related to the advanced preoperative imaging studies, manufacturing of the custom guides, and maintenance of navigation equipment. In addition, while interventions such as the use of barbed suture have the potential for speeding closure time, the time saved (4.7 minutes in one randomized trial)⁷ may not be enough to affect major utilization differences per OR per day. These technologies are also frequently employed by high-volume surgeons with high-volume teams and institutions.

Ideally, we need investment in the human capital and a collective change in work cultures to produce high-quality, well-choreographed, easily reproducible routines. An efficient OR requires the synchronous involvement of a large team of individuals, including hospital administrators, surgery schedulers, surgeons, anesthesiologists, preoperative holding area staff, OR nurses, surgical attendants, sterile processing personnel, and recovery room nurses. Case schedulers should match allocated block time with time required for surgery based on the historical performance of the individual surgeon, preferably scheduling similar cases on the same day. Preoperative work-up and medical clearance should be completed prior to scheduling to avoid last-minute cancellations. Patient reminders and accommodations for those traveling from long distances can further minimize late arrivals. Prompt initiation of the perioperative clinical pathway upon a patient’s check-in is important. The surgical site should be marked and the anesthesia plan confirmed upon arrival in the preoperative holding area. Necessary products need to be ready and/or administrated in time for transfer to the OR. These include prophylactic antibiotics, coagulation factors (eg, tranexamic acid), and blood products as indicated. Spinal anesthesia, regional nerve blocks, and intravenous (IV) lines should be completed before transfer to the OR. A “block room” close to the OR can allow concurrent induction of anesthesia and has been shown to increase the number of surgical cases performed during a regular workday.⁸ Hair clipping within the surgical site and pre-scrubbing of the operative extremity should also be performed prior to transfer to the OR in order to minimize micro-organisms and dispersal of loose hair onto the sterile field.

Upon arrival of the patient to the OR, instrument tables based on the surgeon preference cards should be opened, instrument count and implant templating completed, necessary imaging displayed, and OR staff ready with specific responsibilities assigned to each member. Small and colleagues⁹ showed that using dedicated orthopedic staff familiar with the surgical routine decreased operative time by 19 minutes per procedure, or 1.25 hours for a surgeon performing 4 primary TJAs per day. Practices such as routine placement of a urinary catheter should be seriously scrutinized. In a randomized prospective study of patients undergoing total hip arthroplasty under spinal anesthesia, Miller and colleagues¹⁰ found no benefit for indwelling catheters in preventing urinary retention. In another randomized prospective study, Huang and colleagues¹¹ found the prevalence of urinary tract infections was significantly higher in TJA patients who received indwelling urinary catheters.

A scrub nurse familiar with the instruments, their assembly, and the sequence of events can ensure efficient surgical flow. The scrub nurse needs to anticipate missing or defective tools and call for them, ideally before the incision is made. Direct comparison studies are needed to assess the efficacy of routine intraoperative imaging vs commercially available universal cup alignment guides or clinical examinations in determining acceptable component positioning and limb length. Following component implantation and before wound closure, the circulating nurse should initiate the process of acquisition of a recovery room bed, make sure dressing supplies and necessary equipment are available, and call for surgical attendants. Lack of surgical attendants, delayed transfer from the OR table to hospital bed, and prolonged acquisition of a recovery room bed have been identified as major OR inefficiencies in a retrospective study by Attarian and colleagues.¹²

In summary, time is the OR’s most valuable resource.¹³ We believe that a consistent, almost automated attitude to the above procedures decreases variability and improves efficiency. By providing clear communication of the surgical needs with the team, having consistent anesthesia and nursing staff, implementing consistent perioperative protocols, and insuring that all necessary instruments and modalities are available prior to starting the procedure, we were able to sustainably increase OR throughput in a large teaching hospital.^9,14 This process, however, requires constant review to identify and eliminate new gaps, with each member of the team sharing a frank desire to improve. In this regard, hospital administrators share the duty to facilitate the implementation of any necessary changes, allocation of needed resources, and rewarding good effort, which could ultimately increase staff satisfaction and retention. Because efficiency is the ratio of benefits (eg, revenue, safety, etc.) to investment (eg, implant costs, wages, etc.), raises the question: what would be the effect of transitioning from hourly-wage to a salary-based system for key support staff? Unlike hourly-wage personnel, who have no incentive for productivity, a salaried employee assigned to a high-efficiency OR will inherently strive for improvement, employing higher organizational skills to accomplish a common goal. To our knowledge, there is no published data on this topic.

Developing a high-efficiency operating room (OR) is both a challenging and rewarding goal for any healthcare system. The OR is traditionally a high-cost/high-revenue environment¹ and operative efficacy has been correlated with low complication rates and surgical success.² An efficient OR is one that maximizes utilization while providing safe, reproducible, cost-effective, high-quality care. Total joint arthroplasty (TJA) has occupied the center stage for OR efficiency research, in part due to increasing demands from our aging population³ and economic pressures related to high implant costs, decreased reimbursement, and competition for market shares when OR time and space are limited.

A PubMed search on OR efficiency in TJA shows a disproportionately high focus on surgical technique, such as use of patient-specific instrumentation (PSI), computer-assisted surgery (CAS), minimally invasive surgery, and closure with barbed suture. In a retrospective review of 352 TKA patients who had PSI vs conventional instrumentation, DeHaan and colleagues⁴ found that PSI was associated with significantly decreased operative and room turnover times (20.4 minutes and 6.4 minutes, respectively). In another prospective multicenter study, Mont and colleagues⁵ showed a reduction in surgical time by 8.90 min for navigated total knee arthroplasty (TKA) performed with single-use instruments, cutting blocks, and trials. Other investigators compared PSI to CAS in TKA and found PSI to be 1.45 times more profitable than CAS, with 3 PSI cases performed in an 8-hour OR day compared to 2 CAS cases.⁶

There is no question that improved surgical technique can enhance OR efficiency. However, this model, while promising, is difficult to implement on a wide scale due to surgeon preferences, vendor limitations, and added costs related to the advanced preoperative imaging studies, manufacturing of the custom guides, and maintenance of navigation equipment. In addition, while interventions such as the use of barbed suture have the potential for speeding closure time, the time saved (4.7 minutes in one randomized trial)⁷ may not be enough to affect major utilization differences per OR per day. These technologies are also frequently employed by high-volume surgeons with high-volume teams and institutions.

Ideally, we need investment in the human capital and a collective change in work cultures to produce high-quality, well-choreographed, easily reproducible routines. An efficient OR requires the synchronous involvement of a large team of individuals, including hospital administrators, surgery schedulers, surgeons, anesthesiologists, preoperative holding area staff, OR nurses, surgical attendants, sterile processing personnel, and recovery room nurses. Case schedulers should match allocated block time with time required for surgery based on the historical performance of the individual surgeon, preferably scheduling similar cases on the same day. Preoperative work-up and medical clearance should be completed prior to scheduling to avoid last-minute cancellations. Patient reminders and accommodations for those traveling from long distances can further minimize late arrivals. Prompt initiation of the perioperative clinical pathway upon a patient’s check-in is important. The surgical site should be marked and the anesthesia plan confirmed upon arrival in the preoperative holding area. Necessary products need to be ready and/or administrated in time for transfer to the OR. These include prophylactic antibiotics, coagulation factors (eg, tranexamic acid), and blood products as indicated. Spinal anesthesia, regional nerve blocks, and intravenous (IV) lines should be completed before transfer to the OR. A “block room” close to the OR can allow concurrent induction of anesthesia and has been shown to increase the number of surgical cases performed during a regular workday.⁸ Hair clipping within the surgical site and pre-scrubbing of the operative extremity should also be performed prior to transfer to the OR in order to minimize micro-organisms and dispersal of loose hair onto the sterile field.

Upon arrival of the patient to the OR, instrument tables based on the surgeon preference cards should be opened, instrument count and implant templating completed, necessary imaging displayed, and OR staff ready with specific responsibilities assigned to each member. Small and colleagues⁹ showed that using dedicated orthopedic staff familiar with the surgical routine decreased operative time by 19 minutes per procedure, or 1.25 hours for a surgeon performing 4 primary TJAs per day. Practices such as routine placement of a urinary catheter should be seriously scrutinized. In a randomized prospective study of patients undergoing total hip arthroplasty under spinal anesthesia, Miller and colleagues¹⁰ found no benefit for indwelling catheters in preventing urinary retention. In another randomized prospective study, Huang and colleagues¹¹ found the prevalence of urinary tract infections was significantly higher in TJA patients who received indwelling urinary catheters.

A scrub nurse familiar with the instruments, their assembly, and the sequence of events can ensure efficient surgical flow. The scrub nurse needs to anticipate missing or defective tools and call for them, ideally before the incision is made. Direct comparison studies are needed to assess the efficacy of routine intraoperative imaging vs commercially available universal cup alignment guides or clinical examinations in determining acceptable component positioning and limb length. Following component implantation and before wound closure, the circulating nurse should initiate the process of acquisition of a recovery room bed, make sure dressing supplies and necessary equipment are available, and call for surgical attendants. Lack of surgical attendants, delayed transfer from the OR table to hospital bed, and prolonged acquisition of a recovery room bed have been identified as major OR inefficiencies in a retrospective study by Attarian and colleagues.¹²

In summary, time is the OR’s most valuable resource.¹³ We believe that a consistent, almost automated attitude to the above procedures decreases variability and improves efficiency. By providing clear communication of the surgical needs with the team, having consistent anesthesia and nursing staff, implementing consistent perioperative protocols, and insuring that all necessary instruments and modalities are available prior to starting the procedure, we were able to sustainably increase OR throughput in a large teaching hospital.^9,14 This process, however, requires constant review to identify and eliminate new gaps, with each member of the team sharing a frank desire to improve. In this regard, hospital administrators share the duty to facilitate the implementation of any necessary changes, allocation of needed resources, and rewarding good effort, which could ultimately increase staff satisfaction and retention. Because efficiency is the ratio of benefits (eg, revenue, safety, etc.) to investment (eg, implant costs, wages, etc.), raises the question: what would be the effect of transitioning from hourly-wage to a salary-based system for key support staff? Unlike hourly-wage personnel, who have no incentive for productivity, a salaried employee assigned to a high-efficiency OR will inherently strive for improvement, employing higher organizational skills to accomplish a common goal. To our knowledge, there is no published data on this topic.

Shoulder arthroplasty (SA), including total SA (TSA) and reverse TSA, is an effective surgical treatment for fracture and primary or secondary degenerative disease of the shoulder.¹ Over the past few decades, use of SA has increased dramatically, from about 5000 cases in 1990 to 7000 in 2000 and more than 26,000 in 2008.^1,2

Complications associated with SA generally are classified as perioperative (occurring during the operative index) or long-term (postdischarge).³ Long-term complications include implant loosening, instability, revision, infection, rotator cuff tear, neural injury, and deltoid detachment.^1,4,5 Perioperative complications, which are less commonly reported, include intraoperative fracture, infection, neural injury, venous thromboembolic events (VTEs, including pulmonary embolism [PE] and deep vein thrombosis [DVT]), transfusion, and death.^3,6-10

SA is an attractive treatment option for patients with rheumatoid arthritis (RA), as the effects of pain on these patients are greater in the shoulder joint than in any other joint.¹¹ Patients with RA pose unique orthopedic surgical challenges, including any combination of decreased bone mineralization, poor capsular tissue integrity, and osteonecrosis.^3,12 In addition, RA patients may be taking immunosuppressive medications that have severe side effects, and they may require multiple surgeries.^12,13 These factors predispose patients with RA to complications that include infection and wound dehiscence.^3,5,12-14

The complex nature of RA has prompted investigators to examine outcome measures in this patient group. Hambright and colleagues³ used the Nationwide Inpatient Sample (NIS) to examine perioperative outcomes in RA patients who underwent TSA between 1988 and 2005.³ They found that TSA patients with RA had shorter and less costly hospital stays and were more likely to have a routine discharge.³ Using the same patient population drawn from the period 2006–2011, we conducted a study to determine if this unexpected trend persists as the number of TSAs and quality of postoperative care continue to increase. Given the potential for anemia of chronic disease and the systemic inflammatory nature of RA, we hypothesized that the perioperative complication profile of RA patients would be worse than that of non-RA patients.

Materials and Methods

NIS data were acquired for the period 2006–2011. The NIS is the largest publicly available all-payer inpatient database, with a random 20% sample of about 1000 US hospitals accounting for 7 to 8 million inpatient stays. The database supplies weights used to estimate national totals, at about 35 million inpatient visits per year. NIS inpatient data are limited to the operative index. Postdischarge information is not available. The NIS is managed by the Healthcare Cost and Utilization Project, which is sponsored by the Agency for Healthcare Research and Quality. The quality of NIS data is assessed and validated by an independent contractor. NIS data have been widely used to examine perioperative outcomes.^15-17

NIS data cover patient and hospital demographics, hospital length of stay (LOS), discharge status, payer information, charges, and perioperative outcomes and procedure/diagnosis codes (ICD-9; International Classification of Diseases, Ninth Revision¹⁸).

As our Institutional Review Board (IRB) reviewed the database and determined the project was not human subject research, IRB involvement was not required. This study paralleled successful efforts with similar RA and non-RA patients who had shoulder and elbow surgery.^3,19 SA patients were identified by ICD-9 procedure code 81.80, but this code does not specify whether the prosthesis was unconstrained, semiconstrained, or constrained. ICD-9 coding also does not specify whether the TSA was traditional or reverse. Patients with RA were identified by ICD-9 diagnosis codes 714.0, 714.1, and 714.2. Patients without one of these codes were placed in the non-RA cohort. Patients with codes associated with pathologic fractures secondary to metastatic cancer or bone malignant neoplasm as a secondary or primary diagnosis and patients who had revision surgery indicated by code 81.83 were excluded, as they have a disproportionately higher comorbidity burden.

After each cohort was defined, demographic data (age, sex, race, income quartile based on ZIP postal code) were compared, as were data on primary payer, hospital demographics, LOS (≤5 days, defined as perioperative index), discharge type, inflation-adjusted charges in 2014 dollars based on the Consumer Price Indexes (http://www.bls.gov/cpi/), and mortality. Perioperative complications—respiratory, gastrointestinal, genitourinary, accidental puncture/laceration, central nervous system, wound dehiscence, device-related (including embolism, fibrosis, hemorrhage, pain, stenosis, or thrombus caused by any device, implant, or graft), cardiac, hematoma/seroma, acute respiratory distress syndrome, postoperative shock, VTE, postoperative infection complications, and intraoperative transfusions—were considered using ICD-9 codes (996.X-999.X and 99.X, respectively).²⁰ Although commonly used to determine perioperative comorbidity burden using ICD-9 coding, the modified Charlson index was not considered because RA is a component of the index and would therefore bias the variable.^3,21

Statistical analyses, including χ² tests and 2-sample t tests, were performed for categorical and continuous variables, respectively. P < .05 was considered significant. Fisher exact test was used for cohorts with fewer than 5 occurrences. Multivariate logistic regression models were then calculated to determine the effect of RA on different outcomes and complications, with age, race, sex, hospital region, hospital type, number of hospital beds, primary payer, and hospital ownership as covariates. Statistical analyses were performed using the R statistical programming language.22

Results

Of the 34,970 patients who underwent SA between 2006 and 2011, 1674 (4.8%) had a diagnosis of RA and 33,296 (95.2%) did not. On average, patients with RA tended to be younger than patients without RA (66.4 vs 69.1 years; P < .001), and a larger percentage of RA patients were female (75.5% vs 54.4%; P < .001). Compared with non-RA patients, RA patients comprised a different ethnic group and had a different expected primary payer (P < .001). SA patients with and without RA did not differ in income quartile based on ZIP code, total number of hospital beds, hospital region, or hospital teaching status (P = .34, .78, .59, and .82, respectively) (Table 1).

LOS was significantly (P < .001) statistically longer for RA patients (2.196 days) than for non-RA patients (2.085 days). RA patients were significantly less likely to be discharged home (63.0% vs 67.6%; P < .001). (Routine discharge was defined as discharge home, whereas nonroutine discharge was defined as discharge to a short-term hospital, skilled nursing facility, intermediate care, another type of facility, home health care, against medical advice, or death.) In addition, inflation-adjusted charges associated with SA were significantly higher (P = .018) for RA patients ($54,284) than for non-RA patients ($52,663) (Table 1).

Regarding the rates of complications that occurred during the perioperative index, there were no significant differences between RA and non-RA cohorts. These complications included respiratory, gastrointestinal, genitourinary, accidental puncture/laceration, central nervous system, wound dehiscence, device-related, cardiac, hematoma/seroma, acute respiratory distress syndrome, postoperative shock, VTE, and postoperative infection (Table 2). In addition, there was no significant difference in mortality between the groups (P = .48).

In TSA, blood transfusions were more likely (P < .001) to be given to RA patients (9.00%) than to non-RA patients (6.16%). Multivariate regression analyses were performed with age, race, sex, hospital region, hospital type, number of hospital beds, primary payer, and hospital ownership as covariates. These analyses revealed that transfusion (P < .001), discharge type (P = .002), total inflation-adjusted charges (P < .001), and LOS (P = .047) remained significant (Table 3).

Discussion

Large national databases like NIS allow study of uncommon medical occurrences and help delineate risks and trends that otherwise might be indeterminable. Although it has been suggested that patients with RA may have poorer long-term outcomes after SA, the perioperative risk profile indicates that TSA is well tolerated in RA patients during the operative index.^3,23-25

The data on this study’s 34,970 patients, drawn from the period 2006–2011, demonstrated no significant differences in safety profile with respect to the 14 perioperative complications and outcomes examined, except blood transfusion rate. Rates of postoperative infection (RA, 0.24%; non-RA, 0.14%; P = .303), VTE (RA, 0.30%; non-RA, 0.25%; P = .905), and transfusion (RA, 9.00%; non-RA, 6.16%; P < .001) are of particular interest because of the severity of these situations.

Postoperative infection is a potentially serious complication and often occurs secondary to diabetes, RA, lupus erythematosus, prior surgery, or a nosocomial or remote source.¹ The often costly treatment options include antibiotic suppression, irrigation and debridement with implant retention, 1-stage exchange with antibiotic-impregnated cement fixation, staged reimplantation, resection arthroplasty, arthrodesis, and amputation.¹ The overall 0.14% infection rate determined in this study is lower than the 0.7% reported for SA patients in the literature.¹ Given the nature of the NIS database, this rate underestimates the true postoperative infection rate, as any infection that occurred after the perioperative period is not captured.²⁶ The present study’s perioperative infection rates (RA, 0.24%; non-RA, 0.14%) for the period 2006–2011 are comparable to the rates (RA, 0.17%; non-RA, 0.24%) reported by Hambright and colleagues3 for the same patient population over the preceding, 18-year period (1988–2005) and similarly do not significantly differ between groups. Although infection is uncommon in the immediate perioperative period, the ICD-9 codes used refer specifically to infection resulting from surgery and do not represent concomitant infection.

VTEs, which include PEs and DVTs, are rare but potentially life-threatening surgical complications.^27,28 Mechanical prophylaxis and chemical prophylaxis have been recommended for major orthopedic surgery, particularly lower extremity surgery, such as total hip arthroplasty (THA) and total knee arthroplasty (TKA).^28,29 In the present study, VTE rates were low, 0.30% (RA) and 0.25% (non-RA), and not significantly different in bivariate or multivariate analyses. These rates are comparable to those found in other national-database SA studies.²⁸ VTEs that occur outside the index hospital admission are not captured in this database. Therefore, the rates in the present study may be lower than the true incidence after SA. Mortality secondary to VTE usually occurs within 24 hours but may occur up to 90 days after surgery. DVT rates, on the other hand, are difficult to evaluate because of differences in screening practices.^27,28,30,31

That RA patients were more likely than non-RA patients to receive perioperative blood transfusions supports prior findings that SA patients with RA were more likely than SA patients with osteoarthritis (OA) to receive perioperative blood transfusions.⁸ RA patients have been shown to have high rates of anemia of chronic disease, ranging from 22% to 77%.³² During joint replacement, these patients often require transfusions.^32,33 However, these findings differ from prior findings of no differences between RA and non-RA patients in the same patient population during the period 1988–2005.³ This difference may be a product of the constantly changing transfusion guidelines and increased use; transfusion rates increased 140% between 1997 and 2007, making transfusions the fastest growing common procedure in the United States during that time.³⁴ There was no difference between RA and non-RA patients in household income (as determined by ZIP code analysis), number of hospital beds, hospital region, or hospital teaching status. Compared with non-RA patients, RA patients were more likely to be younger, female, and of a difference race and to have a different expected primary payer (P < .001).These findings are consistent with previous findings in the literature.³ In the present SA study, however, RA patients were more likely than non-RA patients to have longer LOS, higher inflation-adjusted hospital charges, and nonroutine discharge. These findings deviate from those of the study covering the preceding 18 years (1988–2005).³ Despite the findings of a changing environment of care for RA patients, by Hambright and colleagues³ and Weiss and colleagues,³⁵ the trend appears to have shifted. Both groups had shorter average LOS than either group from the preceding 18 years.³ Although statistically significant in bivariate analysis, the difference in LOS between the 2 groups differed by an average of 0.11 day (2 hours 24 minutes) and was not clinically relevant.

In addition, the higher charges for patients with RA represent a deviation from the preceding 18 years.³ Other studies have also shown that RA is associated with increased cost in TSA.³⁶ Patients with RA often have rotator cuff pathology, indicating reverse SA may be used more frequently.^37,38 The increased implant cost associated with reverse SA may account for the increased costs in RA patients.³⁹ As mentioned, TSA type is not captured in the NIS database. In addition, that RA patients were less likely than non-RA patients to have routine discharge may indicate RA cases are more complex because of their complications.^1,5,14,40 A recent study of complications in RA patients (1163 who underwent THA, 2692 who underwent TKA) found that THA patients with RA were significantly more likely than THA patients with OA to dislocate, and TKA patients with RA were significantly more likely than TKA patients with OA to develop an infection after surgery.⁴¹ Postoperative dislocation has been shown to increase hospital costs in other orthopedic procedures.⁴² Also, during TSA, patients with RA are more likely than patients with OA to receive intraoperative blood transfusions.⁸ These complications—combined with the fact that RA is a chronic, progressive, systemic inflammatory disease that can affect soft tissue and blood vessel wall healing and is associated with medications having potential side effects—could contribute to the apparent increased hospital charges and LOS.^3,12,13,43 Factors that include surgeon preference, impact of primary payer, and hospital practice may also affect final charges. Total charges in the NIS database include administrative fees, hospital costs, device-related costs, operating room costs, and ancillary staff costs. Total charges do not include professional fees and differ from the total cost that represents the amount reimbursed by the payer. Charges tend to correlate with but overestimate the total costs.⁴⁴

This study had several important limitations. As mentioned, only events that occur during the operative admission are captured in the NIS database, and thus postoperative complications or serious adverse events that lead to readmission cannot be identified. In addition, outpatient TSAs are not captured in the NIS database, and thus inclusion of only inpatient procedures yields higher average LOS and total charges.⁴⁵ Given the limited granularity of ICD-9 coding, this study could not determine RA severity, estimated blood loss, length of surgery, complication severity, type of TSA procedure/prosthesis, or cause of death. Although commonly used to determine comorbidity burden, the modified Charlson index could not be used, and therefore could not be entered as a covariate in multivariate analysis. Furthermore, the NIS database does not include imaging or patient-reported outcomes information, such as improvements in pain or function, which are of crucial importance in considering surgery.

Conclusion

Our findings corroborated findings that the demographics and the perioperative safety profile for TSA were similar for patients with and without RA. The risk for complications or death in the perioperative period was low. Compared with non-RA patients, RA patients had significantly higher charges and longer LOS and were less likely to be discharged home after surgery. The 0.11-day difference in LOS, though statistically significant, was not clinically relevant. These findings differ from those for the preceding, 18-year period (1988–2005). Future research should focus on the causes of these changes.

Shoulder arthroplasty (SA), including total SA (TSA) and reverse TSA, is an effective surgical treatment for fracture and primary or secondary degenerative disease of the shoulder.¹ Over the past few decades, use of SA has increased dramatically, from about 5000 cases in 1990 to 7000 in 2000 and more than 26,000 in 2008.^1,2

Complications associated with SA generally are classified as perioperative (occurring during the operative index) or long-term (postdischarge).³ Long-term complications include implant loosening, instability, revision, infection, rotator cuff tear, neural injury, and deltoid detachment.^1,4,5 Perioperative complications, which are less commonly reported, include intraoperative fracture, infection, neural injury, venous thromboembolic events (VTEs, including pulmonary embolism [PE] and deep vein thrombosis [DVT]), transfusion, and death.^3,6-10

SA is an attractive treatment option for patients with rheumatoid arthritis (RA), as the effects of pain on these patients are greater in the shoulder joint than in any other joint.¹¹ Patients with RA pose unique orthopedic surgical challenges, including any combination of decreased bone mineralization, poor capsular tissue integrity, and osteonecrosis.^3,12 In addition, RA patients may be taking immunosuppressive medications that have severe side effects, and they may require multiple surgeries.^12,13 These factors predispose patients with RA to complications that include infection and wound dehiscence.^3,5,12-14

The complex nature of RA has prompted investigators to examine outcome measures in this patient group. Hambright and colleagues³ used the Nationwide Inpatient Sample (NIS) to examine perioperative outcomes in RA patients who underwent TSA between 1988 and 2005.³ They found that TSA patients with RA had shorter and less costly hospital stays and were more likely to have a routine discharge.³ Using the same patient population drawn from the period 2006–2011, we conducted a study to determine if this unexpected trend persists as the number of TSAs and quality of postoperative care continue to increase. Given the potential for anemia of chronic disease and the systemic inflammatory nature of RA, we hypothesized that the perioperative complication profile of RA patients would be worse than that of non-RA patients.

Materials and Methods

NIS data were acquired for the period 2006–2011. The NIS is the largest publicly available all-payer inpatient database, with a random 20% sample of about 1000 US hospitals accounting for 7 to 8 million inpatient stays. The database supplies weights used to estimate national totals, at about 35 million inpatient visits per year. NIS inpatient data are limited to the operative index. Postdischarge information is not available. The NIS is managed by the Healthcare Cost and Utilization Project, which is sponsored by the Agency for Healthcare Research and Quality. The quality of NIS data is assessed and validated by an independent contractor. NIS data have been widely used to examine perioperative outcomes.^15-17

NIS data cover patient and hospital demographics, hospital length of stay (LOS), discharge status, payer information, charges, and perioperative outcomes and procedure/diagnosis codes (ICD-9; International Classification of Diseases, Ninth Revision¹⁸).

As our Institutional Review Board (IRB) reviewed the database and determined the project was not human subject research, IRB involvement was not required. This study paralleled successful efforts with similar RA and non-RA patients who had shoulder and elbow surgery.^3,19 SA patients were identified by ICD-9 procedure code 81.80, but this code does not specify whether the prosthesis was unconstrained, semiconstrained, or constrained. ICD-9 coding also does not specify whether the TSA was traditional or reverse. Patients with RA were identified by ICD-9 diagnosis codes 714.0, 714.1, and 714.2. Patients without one of these codes were placed in the non-RA cohort. Patients with codes associated with pathologic fractures secondary to metastatic cancer or bone malignant neoplasm as a secondary or primary diagnosis and patients who had revision surgery indicated by code 81.83 were excluded, as they have a disproportionately higher comorbidity burden.

After each cohort was defined, demographic data (age, sex, race, income quartile based on ZIP postal code) were compared, as were data on primary payer, hospital demographics, LOS (≤5 days, defined as perioperative index), discharge type, inflation-adjusted charges in 2014 dollars based on the Consumer Price Indexes (http://www.bls.gov/cpi/), and mortality. Perioperative complications—respiratory, gastrointestinal, genitourinary, accidental puncture/laceration, central nervous system, wound dehiscence, device-related (including embolism, fibrosis, hemorrhage, pain, stenosis, or thrombus caused by any device, implant, or graft), cardiac, hematoma/seroma, acute respiratory distress syndrome, postoperative shock, VTE, postoperative infection complications, and intraoperative transfusions—were considered using ICD-9 codes (996.X-999.X and 99.X, respectively).²⁰ Although commonly used to determine perioperative comorbidity burden using ICD-9 coding, the modified Charlson index was not considered because RA is a component of the index and would therefore bias the variable.^3,21

Statistical analyses, including χ² tests and 2-sample t tests, were performed for categorical and continuous variables, respectively. P < .05 was considered significant. Fisher exact test was used for cohorts with fewer than 5 occurrences. Multivariate logistic regression models were then calculated to determine the effect of RA on different outcomes and complications, with age, race, sex, hospital region, hospital type, number of hospital beds, primary payer, and hospital ownership as covariates. Statistical analyses were performed using the R statistical programming language.22

Results

Of the 34,970 patients who underwent SA between 2006 and 2011, 1674 (4.8%) had a diagnosis of RA and 33,296 (95.2%) did not. On average, patients with RA tended to be younger than patients without RA (66.4 vs 69.1 years; P < .001), and a larger percentage of RA patients were female (75.5% vs 54.4%; P < .001). Compared with non-RA patients, RA patients comprised a different ethnic group and had a different expected primary payer (P < .001). SA patients with and without RA did not differ in income quartile based on ZIP code, total number of hospital beds, hospital region, or hospital teaching status (P = .34, .78, .59, and .82, respectively) (Table 1).

LOS was significantly (P < .001) statistically longer for RA patients (2.196 days) than for non-RA patients (2.085 days). RA patients were significantly less likely to be discharged home (63.0% vs 67.6%; P < .001). (Routine discharge was defined as discharge home, whereas nonroutine discharge was defined as discharge to a short-term hospital, skilled nursing facility, intermediate care, another type of facility, home health care, against medical advice, or death.) In addition, inflation-adjusted charges associated with SA were significantly higher (P = .018) for RA patients ($54,284) than for non-RA patients ($52,663) (Table 1).

Regarding the rates of complications that occurred during the perioperative index, there were no significant differences between RA and non-RA cohorts. These complications included respiratory, gastrointestinal, genitourinary, accidental puncture/laceration, central nervous system, wound dehiscence, device-related, cardiac, hematoma/seroma, acute respiratory distress syndrome, postoperative shock, VTE, and postoperative infection (Table 2). In addition, there was no significant difference in mortality between the groups (P = .48).

In TSA, blood transfusions were more likely (P < .001) to be given to RA patients (9.00%) than to non-RA patients (6.16%). Multivariate regression analyses were performed with age, race, sex, hospital region, hospital type, number of hospital beds, primary payer, and hospital ownership as covariates. These analyses revealed that transfusion (P < .001), discharge type (P = .002), total inflation-adjusted charges (P < .001), and LOS (P = .047) remained significant (Table 3).

Discussion

Large national databases like NIS allow study of uncommon medical occurrences and help delineate risks and trends that otherwise might be indeterminable. Although it has been suggested that patients with RA may have poorer long-term outcomes after SA, the perioperative risk profile indicates that TSA is well tolerated in RA patients during the operative index.^3,23-25

The data on this study’s 34,970 patients, drawn from the period 2006–2011, demonstrated no significant differences in safety profile with respect to the 14 perioperative complications and outcomes examined, except blood transfusion rate. Rates of postoperative infection (RA, 0.24%; non-RA, 0.14%; P = .303), VTE (RA, 0.30%; non-RA, 0.25%; P = .905), and transfusion (RA, 9.00%; non-RA, 6.16%; P < .001) are of particular interest because of the severity of these situations.

Postoperative infection is a potentially serious complication and often occurs secondary to diabetes, RA, lupus erythematosus, prior surgery, or a nosocomial or remote source.¹ The often costly treatment options include antibiotic suppression, irrigation and debridement with implant retention, 1-stage exchange with antibiotic-impregnated cement fixation, staged reimplantation, resection arthroplasty, arthrodesis, and amputation.¹ The overall 0.14% infection rate determined in this study is lower than the 0.7% reported for SA patients in the literature.¹ Given the nature of the NIS database, this rate underestimates the true postoperative infection rate, as any infection that occurred after the perioperative period is not captured.²⁶ The present study’s perioperative infection rates (RA, 0.24%; non-RA, 0.14%) for the period 2006–2011 are comparable to the rates (RA, 0.17%; non-RA, 0.24%) reported by Hambright and colleagues3 for the same patient population over the preceding, 18-year period (1988–2005) and similarly do not significantly differ between groups. Although infection is uncommon in the immediate perioperative period, the ICD-9 codes used refer specifically to infection resulting from surgery and do not represent concomitant infection.

VTEs, which include PEs and DVTs, are rare but potentially life-threatening surgical complications.^27,28 Mechanical prophylaxis and chemical prophylaxis have been recommended for major orthopedic surgery, particularly lower extremity surgery, such as total hip arthroplasty (THA) and total knee arthroplasty (TKA).^28,29 In the present study, VTE rates were low, 0.30% (RA) and 0.25% (non-RA), and not significantly different in bivariate or multivariate analyses. These rates are comparable to those found in other national-database SA studies.²⁸ VTEs that occur outside the index hospital admission are not captured in this database. Therefore, the rates in the present study may be lower than the true incidence after SA. Mortality secondary to VTE usually occurs within 24 hours but may occur up to 90 days after surgery. DVT rates, on the other hand, are difficult to evaluate because of differences in screening practices.^27,28,30,31

That RA patients were more likely than non-RA patients to receive perioperative blood transfusions supports prior findings that SA patients with RA were more likely than SA patients with osteoarthritis (OA) to receive perioperative blood transfusions.⁸ RA patients have been shown to have high rates of anemia of chronic disease, ranging from 22% to 77%.³² During joint replacement, these patients often require transfusions.^32,33 However, these findings differ from prior findings of no differences between RA and non-RA patients in the same patient population during the period 1988–2005.³ This difference may be a product of the constantly changing transfusion guidelines and increased use; transfusion rates increased 140% between 1997 and 2007, making transfusions the fastest growing common procedure in the United States during that time.³⁴ There was no difference between RA and non-RA patients in household income (as determined by ZIP code analysis), number of hospital beds, hospital region, or hospital teaching status. Compared with non-RA patients, RA patients were more likely to be younger, female, and of a difference race and to have a different expected primary payer (P < .001).These findings are consistent with previous findings in the literature.³ In the present SA study, however, RA patients were more likely than non-RA patients to have longer LOS, higher inflation-adjusted hospital charges, and nonroutine discharge. These findings deviate from those of the study covering the preceding 18 years (1988–2005).³ Despite the findings of a changing environment of care for RA patients, by Hambright and colleagues³ and Weiss and colleagues,³⁵ the trend appears to have shifted. Both groups had shorter average LOS than either group from the preceding 18 years.³ Although statistically significant in bivariate analysis, the difference in LOS between the 2 groups differed by an average of 0.11 day (2 hours 24 minutes) and was not clinically relevant.

In addition, the higher charges for patients with RA represent a deviation from the preceding 18 years.³ Other studies have also shown that RA is associated with increased cost in TSA.³⁶ Patients with RA often have rotator cuff pathology, indicating reverse SA may be used more frequently.^37,38 The increased implant cost associated with reverse SA may account for the increased costs in RA patients.³⁹ As mentioned, TSA type is not captured in the NIS database. In addition, that RA patients were less likely than non-RA patients to have routine discharge may indicate RA cases are more complex because of their complications.^1,5,14,40 A recent study of complications in RA patients (1163 who underwent THA, 2692 who underwent TKA) found that THA patients with RA were significantly more likely than THA patients with OA to dislocate, and TKA patients with RA were significantly more likely than TKA patients with OA to develop an infection after surgery.⁴¹ Postoperative dislocation has been shown to increase hospital costs in other orthopedic procedures.⁴² Also, during TSA, patients with RA are more likely than patients with OA to receive intraoperative blood transfusions.⁸ These complications—combined with the fact that RA is a chronic, progressive, systemic inflammatory disease that can affect soft tissue and blood vessel wall healing and is associated with medications having potential side effects—could contribute to the apparent increased hospital charges and LOS.^3,12,13,43 Factors that include surgeon preference, impact of primary payer, and hospital practice may also affect final charges. Total charges in the NIS database include administrative fees, hospital costs, device-related costs, operating room costs, and ancillary staff costs. Total charges do not include professional fees and differ from the total cost that represents the amount reimbursed by the payer. Charges tend to correlate with but overestimate the total costs.⁴⁴

This study had several important limitations. As mentioned, only events that occur during the operative admission are captured in the NIS database, and thus postoperative complications or serious adverse events that lead to readmission cannot be identified. In addition, outpatient TSAs are not captured in the NIS database, and thus inclusion of only inpatient procedures yields higher average LOS and total charges.⁴⁵ Given the limited granularity of ICD-9 coding, this study could not determine RA severity, estimated blood loss, length of surgery, complication severity, type of TSA procedure/prosthesis, or cause of death. Although commonly used to determine comorbidity burden, the modified Charlson index could not be used, and therefore could not be entered as a covariate in multivariate analysis. Furthermore, the NIS database does not include imaging or patient-reported outcomes information, such as improvements in pain or function, which are of crucial importance in considering surgery.

Conclusion

Our findings corroborated findings that the demographics and the perioperative safety profile for TSA were similar for patients with and without RA. The risk for complications or death in the perioperative period was low. Compared with non-RA patients, RA patients had significantly higher charges and longer LOS and were less likely to be discharged home after surgery. The 0.11-day difference in LOS, though statistically significant, was not clinically relevant. These findings differ from those for the preceding, 18-year period (1988–2005). Future research should focus on the causes of these changes.

Shoulder arthroplasty (SA), including total SA (TSA) and reverse TSA, is an effective surgical treatment for fracture and primary or secondary degenerative disease of the shoulder.¹ Over the past few decades, use of SA has increased dramatically, from about 5000 cases in 1990 to 7000 in 2000 and more than 26,000 in 2008.^1,2

Complications associated with SA generally are classified as perioperative (occurring during the operative index) or long-term (postdischarge).³ Long-term complications include implant loosening, instability, revision, infection, rotator cuff tear, neural injury, and deltoid detachment.^1,4,5 Perioperative complications, which are less commonly reported, include intraoperative fracture, infection, neural injury, venous thromboembolic events (VTEs, including pulmonary embolism [PE] and deep vein thrombosis [DVT]), transfusion, and death.^3,6-10

SA is an attractive treatment option for patients with rheumatoid arthritis (RA), as the effects of pain on these patients are greater in the shoulder joint than in any other joint.¹¹ Patients with RA pose unique orthopedic surgical challenges, including any combination of decreased bone mineralization, poor capsular tissue integrity, and osteonecrosis.^3,12 In addition, RA patients may be taking immunosuppressive medications that have severe side effects, and they may require multiple surgeries.^12,13 These factors predispose patients with RA to complications that include infection and wound dehiscence.^3,5,12-14

The complex nature of RA has prompted investigators to examine outcome measures in this patient group. Hambright and colleagues³ used the Nationwide Inpatient Sample (NIS) to examine perioperative outcomes in RA patients who underwent TSA between 1988 and 2005.³ They found that TSA patients with RA had shorter and less costly hospital stays and were more likely to have a routine discharge.³ Using the same patient population drawn from the period 2006–2011, we conducted a study to determine if this unexpected trend persists as the number of TSAs and quality of postoperative care continue to increase. Given the potential for anemia of chronic disease and the systemic inflammatory nature of RA, we hypothesized that the perioperative complication profile of RA patients would be worse than that of non-RA patients.

Materials and Methods

NIS data were acquired for the period 2006–2011. The NIS is the largest publicly available all-payer inpatient database, with a random 20% sample of about 1000 US hospitals accounting for 7 to 8 million inpatient stays. The database supplies weights used to estimate national totals, at about 35 million inpatient visits per year. NIS inpatient data are limited to the operative index. Postdischarge information is not available. The NIS is managed by the Healthcare Cost and Utilization Project, which is sponsored by the Agency for Healthcare Research and Quality. The quality of NIS data is assessed and validated by an independent contractor. NIS data have been widely used to examine perioperative outcomes.^15-17

NIS data cover patient and hospital demographics, hospital length of stay (LOS), discharge status, payer information, charges, and perioperative outcomes and procedure/diagnosis codes (ICD-9; International Classification of Diseases, Ninth Revision¹⁸).

As our Institutional Review Board (IRB) reviewed the database and determined the project was not human subject research, IRB involvement was not required. This study paralleled successful efforts with similar RA and non-RA patients who had shoulder and elbow surgery.^3,19 SA patients were identified by ICD-9 procedure code 81.80, but this code does not specify whether the prosthesis was unconstrained, semiconstrained, or constrained. ICD-9 coding also does not specify whether the TSA was traditional or reverse. Patients with RA were identified by ICD-9 diagnosis codes 714.0, 714.1, and 714.2. Patients without one of these codes were placed in the non-RA cohort. Patients with codes associated with pathologic fractures secondary to metastatic cancer or bone malignant neoplasm as a secondary or primary diagnosis and patients who had revision surgery indicated by code 81.83 were excluded, as they have a disproportionately higher comorbidity burden.

After each cohort was defined, demographic data (age, sex, race, income quartile based on ZIP postal code) were compared, as were data on primary payer, hospital demographics, LOS (≤5 days, defined as perioperative index), discharge type, inflation-adjusted charges in 2014 dollars based on the Consumer Price Indexes (http://www.bls.gov/cpi/), and mortality. Perioperative complications—respiratory, gastrointestinal, genitourinary, accidental puncture/laceration, central nervous system, wound dehiscence, device-related (including embolism, fibrosis, hemorrhage, pain, stenosis, or thrombus caused by any device, implant, or graft), cardiac, hematoma/seroma, acute respiratory distress syndrome, postoperative shock, VTE, postoperative infection complications, and intraoperative transfusions—were considered using ICD-9 codes (996.X-999.X and 99.X, respectively).²⁰ Although commonly used to determine perioperative comorbidity burden using ICD-9 coding, the modified Charlson index was not considered because RA is a component of the index and would therefore bias the variable.^3,21

Statistical analyses, including χ² tests and 2-sample t tests, were performed for categorical and continuous variables, respectively. P < .05 was considered significant. Fisher exact test was used for cohorts with fewer than 5 occurrences. Multivariate logistic regression models were then calculated to determine the effect of RA on different outcomes and complications, with age, race, sex, hospital region, hospital type, number of hospital beds, primary payer, and hospital ownership as covariates. Statistical analyses were performed using the R statistical programming language.22

Results

Of the 34,970 patients who underwent SA between 2006 and 2011, 1674 (4.8%) had a diagnosis of RA and 33,296 (95.2%) did not. On average, patients with RA tended to be younger than patients without RA (66.4 vs 69.1 years; P < .001), and a larger percentage of RA patients were female (75.5% vs 54.4%; P < .001). Compared with non-RA patients, RA patients comprised a different ethnic group and had a different expected primary payer (P < .001). SA patients with and without RA did not differ in income quartile based on ZIP code, total number of hospital beds, hospital region, or hospital teaching status (P = .34, .78, .59, and .82, respectively) (Table 1).

LOS was significantly (P < .001) statistically longer for RA patients (2.196 days) than for non-RA patients (2.085 days). RA patients were significantly less likely to be discharged home (63.0% vs 67.6%; P < .001). (Routine discharge was defined as discharge home, whereas nonroutine discharge was defined as discharge to a short-term hospital, skilled nursing facility, intermediate care, another type of facility, home health care, against medical advice, or death.) In addition, inflation-adjusted charges associated with SA were significantly higher (P = .018) for RA patients ($54,284) than for non-RA patients ($52,663) (Table 1).

Regarding the rates of complications that occurred during the perioperative index, there were no significant differences between RA and non-RA cohorts. These complications included respiratory, gastrointestinal, genitourinary, accidental puncture/laceration, central nervous system, wound dehiscence, device-related, cardiac, hematoma/seroma, acute respiratory distress syndrome, postoperative shock, VTE, and postoperative infection (Table 2). In addition, there was no significant difference in mortality between the groups (P = .48).

In TSA, blood transfusions were more likely (P < .001) to be given to RA patients (9.00%) than to non-RA patients (6.16%). Multivariate regression analyses were performed with age, race, sex, hospital region, hospital type, number of hospital beds, primary payer, and hospital ownership as covariates. These analyses revealed that transfusion (P < .001), discharge type (P = .002), total inflation-adjusted charges (P < .001), and LOS (P = .047) remained significant (Table 3).

Discussion

Large national databases like NIS allow study of uncommon medical occurrences and help delineate risks and trends that otherwise might be indeterminable. Although it has been suggested that patients with RA may have poorer long-term outcomes after SA, the perioperative risk profile indicates that TSA is well tolerated in RA patients during the operative index.^3,23-25

The data on this study’s 34,970 patients, drawn from the period 2006–2011, demonstrated no significant differences in safety profile with respect to the 14 perioperative complications and outcomes examined, except blood transfusion rate. Rates of postoperative infection (RA, 0.24%; non-RA, 0.14%; P = .303), VTE (RA, 0.30%; non-RA, 0.25%; P = .905), and transfusion (RA, 9.00%; non-RA, 6.16%; P < .001) are of particular interest because of the severity of these situations.

Postoperative infection is a potentially serious complication and often occurs secondary to diabetes, RA, lupus erythematosus, prior surgery, or a nosocomial or remote source.¹ The often costly treatment options include antibiotic suppression, irrigation and debridement with implant retention, 1-stage exchange with antibiotic-impregnated cement fixation, staged reimplantation, resection arthroplasty, arthrodesis, and amputation.¹ The overall 0.14% infection rate determined in this study is lower than the 0.7% reported for SA patients in the literature.¹ Given the nature of the NIS database, this rate underestimates the true postoperative infection rate, as any infection that occurred after the perioperative period is not captured.²⁶ The present study’s perioperative infection rates (RA, 0.24%; non-RA, 0.14%) for the period 2006–2011 are comparable to the rates (RA, 0.17%; non-RA, 0.24%) reported by Hambright and colleagues3 for the same patient population over the preceding, 18-year period (1988–2005) and similarly do not significantly differ between groups. Although infection is uncommon in the immediate perioperative period, the ICD-9 codes used refer specifically to infection resulting from surgery and do not represent concomitant infection.

VTEs, which include PEs and DVTs, are rare but potentially life-threatening surgical complications.^27,28 Mechanical prophylaxis and chemical prophylaxis have been recommended for major orthopedic surgery, particularly lower extremity surgery, such as total hip arthroplasty (THA) and total knee arthroplasty (TKA).^28,29 In the present study, VTE rates were low, 0.30% (RA) and 0.25% (non-RA), and not significantly different in bivariate or multivariate analyses. These rates are comparable to those found in other national-database SA studies.²⁸ VTEs that occur outside the index hospital admission are not captured in this database. Therefore, the rates in the present study may be lower than the true incidence after SA. Mortality secondary to VTE usually occurs within 24 hours but may occur up to 90 days after surgery. DVT rates, on the other hand, are difficult to evaluate because of differences in screening practices.^27,28,30,31

That RA patients were more likely than non-RA patients to receive perioperative blood transfusions supports prior findings that SA patients with RA were more likely than SA patients with osteoarthritis (OA) to receive perioperative blood transfusions.⁸ RA patients have been shown to have high rates of anemia of chronic disease, ranging from 22% to 77%.³² During joint replacement, these patients often require transfusions.^32,33 However, these findings differ from prior findings of no differences between RA and non-RA patients in the same patient population during the period 1988–2005.³ This difference may be a product of the constantly changing transfusion guidelines and increased use; transfusion rates increased 140% between 1997 and 2007, making transfusions the fastest growing common procedure in the United States during that time.³⁴ There was no difference between RA and non-RA patients in household income (as determined by ZIP code analysis), number of hospital beds, hospital region, or hospital teaching status. Compared with non-RA patients, RA patients were more likely to be younger, female, and of a difference race and to have a different expected primary payer (P < .001).These findings are consistent with previous findings in the literature.³ In the present SA study, however, RA patients were more likely than non-RA patients to have longer LOS, higher inflation-adjusted hospital charges, and nonroutine discharge. These findings deviate from those of the study covering the preceding 18 years (1988–2005).³ Despite the findings of a changing environment of care for RA patients, by Hambright and colleagues³ and Weiss and colleagues,³⁵ the trend appears to have shifted. Both groups had shorter average LOS than either group from the preceding 18 years.³ Although statistically significant in bivariate analysis, the difference in LOS between the 2 groups differed by an average of 0.11 day (2 hours 24 minutes) and was not clinically relevant.

In addition, the higher charges for patients with RA represent a deviation from the preceding 18 years.³ Other studies have also shown that RA is associated with increased cost in TSA.³⁶ Patients with RA often have rotator cuff pathology, indicating reverse SA may be used more frequently.^37,38 The increased implant cost associated with reverse SA may account for the increased costs in RA patients.³⁹ As mentioned, TSA type is not captured in the NIS database. In addition, that RA patients were less likely than non-RA patients to have routine discharge may indicate RA cases are more complex because of their complications.^1,5,14,40 A recent study of complications in RA patients (1163 who underwent THA, 2692 who underwent TKA) found that THA patients with RA were significantly more likely than THA patients with OA to dislocate, and TKA patients with RA were significantly more likely than TKA patients with OA to develop an infection after surgery.⁴¹ Postoperative dislocation has been shown to increase hospital costs in other orthopedic procedures.⁴² Also, during TSA, patients with RA are more likely than patients with OA to receive intraoperative blood transfusions.⁸ These complications—combined with the fact that RA is a chronic, progressive, systemic inflammatory disease that can affect soft tissue and blood vessel wall healing and is associated with medications having potential side effects—could contribute to the apparent increased hospital charges and LOS.^3,12,13,43 Factors that include surgeon preference, impact of primary payer, and hospital practice may also affect final charges. Total charges in the NIS database include administrative fees, hospital costs, device-related costs, operating room costs, and ancillary staff costs. Total charges do not include professional fees and differ from the total cost that represents the amount reimbursed by the payer. Charges tend to correlate with but overestimate the total costs.⁴⁴

This study had several important limitations. As mentioned, only events that occur during the operative admission are captured in the NIS database, and thus postoperative complications or serious adverse events that lead to readmission cannot be identified. In addition, outpatient TSAs are not captured in the NIS database, and thus inclusion of only inpatient procedures yields higher average LOS and total charges.⁴⁵ Given the limited granularity of ICD-9 coding, this study could not determine RA severity, estimated blood loss, length of surgery, complication severity, type of TSA procedure/prosthesis, or cause of death. Although commonly used to determine comorbidity burden, the modified Charlson index could not be used, and therefore could not be entered as a covariate in multivariate analysis. Furthermore, the NIS database does not include imaging or patient-reported outcomes information, such as improvements in pain or function, which are of crucial importance in considering surgery.

Conclusion

Our findings corroborated findings that the demographics and the perioperative safety profile for TSA were similar for patients with and without RA. The risk for complications or death in the perioperative period was low. Compared with non-RA patients, RA patients had significantly higher charges and longer LOS and were less likely to be discharged home after surgery. The 0.11-day difference in LOS, though statistically significant, was not clinically relevant. These findings differ from those for the preceding, 18-year period (1988–2005). Future research should focus on the causes of these changes.

Anterior cruciate ligament (ACL) injuries affect >175,000 people each year,¹ with >100,000 Americans undergoing ACL reconstruction annually.² Due to the high impact this injury has on the general population, and especially on athletes, it is important to determine the factors that influence a patient’s selection of a particular graft type. With increasing access to information and other outside influences, surgeons should attempt to provide as much objective information as possible in order to allow patients to make appropriate informed decisions regarding their graft choice for ACL surgery.

While autografts are used in >60% of primary ACL reconstructions, allografts are used in >80% of revision procedures.³ Both autografts and allografts offer advantages and disadvantages, and the advantages of each may depend on patient age, activity level, and occupation.⁴ For example, graft rerupture rates have been shown to be higher in patients with ACL allografts⁴, while kneeling pain has been shown to be worse in patients with bone-patellar tendon-bone (BPTB) autografts compared to hamstring autografts⁵ as well as BPTB allografts.⁴

Patient satisfaction rates are high for ACL autografts and allografts. Boonriong and Kietsiriroje⁶ have shown visual analog scale (VAS) patient satisfaction score averages to be 88 out of 100 for BPTB autografts and 93 out of 100 for hamstring tendon autografts. Fox and colleagues⁷ showed that 87% of patients were completely or mostly satisfied following revision ACL reconstruction with patellar tendon allograft. Cohen and colleagues⁸ evaluated 240 patients undergoing primary ACL reconstruction; 63.3% underwent ACL reconstruction with an allograft and 35.4% with an autograft. Of all patients enrolled in the study, 93% were satisfied with their graft choice, with 12.7% of patients opting to choose another graft if in the same situation again. Of those patients, 63.3% would have switched from an autograft to allograft. Although these numbers represent high patient satisfaction following a variety of ACL graft types, it is important to continue to identify graft selection factors in order to maximize patient outcomes.

The purposes of this prospective study were to assess patients’ knowledge of their graft type used for ACL reconstruction, to determine the most influential factors involved in graft selection, and to determine the level of satisfaction with the graft of choice at a minimum of 1-year follow-up. Based on a previous retrospective study,8 we hypothesized that physician recommendation would be the most influential factor in ACL graft selection. We also hypothesized that patients receiving an autograft would be more accurate in stating their graft harvest location compared to allograft patients.

Materials and Methods

We prospectively enrolled 304 patients who underwent primary ACL reconstruction from January 2008 to September 2013. Surgery was performed by 9 different surgeons within the same practice. All patients undergoing primary ACL reconstruction were eligible for the study.

All surgeons explained to each patient the pros and cons of each graft choice based upon peer-reviewed literature. Each patient was allowed to choose autograft or allograft, although most of the surgeons strongly encourage patients under age 25 years to choose autograft. One of the surgeons specifically encourages a patellar tendon autograft in patients under age 30 to 35 years, except for those patients with a narrow patellar tendon on magnetic resonance imaging, in which case he recommends a hamstring autograft. Another surgeon also specifically encourages patellar tendon autograft in patients under 35 years, except in skeletally immature patients, for whom he encourages hamstring autograft. However, none of the surgeons prohibited patients from choosing autograft or allograft, regardless of age.

The Institutional Review Board at our institution provided approval for this study. At the first postoperative follow-up appointment, each patient completed a questionnaire asking to select from a list the type (“your own” or “a cadaver”) and harvest site of the graft that was used for the surgery. Patients were also asked how they decided upon that graft type by ranking a list of 4 factors from 1 to 4. These included (1) physician recommendation, (2) family/friend’s recommendation, (3) coach’s recommendation, and (4) the media. Patients had the option of ranking more than one factor as most important in their decision. In addition, patients were asked to list any other factors that influenced their decision regarding graft type.

At a minimum of 1 year following surgery, patients completed the same questionnaire described above. In addition, patients were asked if they were satisfied with their graft and whether they would choose the same graft type if undergoing ACL reconstruction again. Patients who would have chosen a different graft were asked which graft they would have chosen and why. Any patient who experienced graft rupture prior to follow-up was included in the analysis.

Statistical Analysis

Chi square tests were used to compare dichotomous outcomes. A type I error of less than 5% (P < .05) was considered statistically significant.

Results

At least 1 year following ACL reconstruction, 213 of 304 patients (70%) successfully completed the same questionnaire as they did at their first postoperative follow-up appointment. The mean age of these patients at the time of surgery was 31.9 ± 11.0 years (range, 13.9 to 58.0 years). The mean follow-up time was 1.4 ± 0.4 years (range, 1.0 to 2.6 years), and 59% of these patients were male.

Autografts were used for 139 patients (139/304, 46%), allografts for 156 patients (156/304, 51%), and hybrid grafts for 9 patients (9/304, 3%). Overall, 77% of patients were accurate in stating the type of graft used for their ACL reconstruction, including 88% of autograft patients, 71% of allograft patients, and 11% of hybrid graft patients (Table 1). Patients who underwent reconstruction with an autograft were significantly more accurate in stating their graft type compared to patients with an allograft (P < .001). Graft type by surgeon is shown in Table 2. A statistically significant difference was found in the proportion of patients choosing autograft versus allograft based on surgeon (P < .0001).

When asked which type of graft was used for their surgery, 12 of 304 patients (4%) did not know their graft type or harvest location. Twenty-nine patients stated that their graft was an allograft but did not know the harvest location. Five patients stated that their graft was an autograft but did not know the harvest location. The 34 patients who classified their choice of graft but did not know the harvest site (11%) stated their surgeon never told them where their graft was from or they did not remember. A complete list of graft type responses is shown in Table 3.

Of the 29 patients who stated that their graft was an allograft but did not know the harvest location, 19 (66%) had a tibialis anterior allograft, 7 (24%) had a BPTB allograft, 2 (7%) had an Achilles tendon allograft, and 1 (3%) had a tibialis anterior autograft.

Physician recommendation was the most important decision-making factor listed for 82% of patients at their first postoperative appointment (Table 4). In addition to the 4 factors listed on our survey, patients were allowed to write in other factors involved in their decision. The most popular answers included recovery time, personal research on graft types, and prior personal experience with ACL reconstruction on the contralateral knee.

At the time of 1-year follow-up, 205 of 213 patients (96%) said they were satisfied with their graft choice (Table 5). All 4 unsatisfied autograft patients received a hamstring autograft, 3 of which were performed by the same surgeon. No significant difference was found in satisfaction rates between patients with autograft vs allograft (P = .87). There was a higher satisfaction rate among patients with a BPTB autograft compared to those with a hamstring autograft (P = .043). Of the unsatisfied patients, 3 patients stated that their graft had failed in the time prior to follow-up and 2 patients stated that they were having donor site pain following surgery with hamstring autograft and would consider an allograft if the reconstruction were repeated (Table 6). Two patients stated that they were unsatisfied with their graft but would need to do more research before deciding on a different graft type.

As shown in Tables 5 and 6, there is a discrepancy between the number of patients who were unsatisfied with their graft and the number of patients who stated that they would switch to a different graft type if they were to have ACL reconstruction again. A number of patients stated that they were satisfied with their graft, yet they would switch to a different graft. The main reasons for this related to issues from a hamstring autograft harvest site. One patient noted that although she was satisfied with her graft, she would switch after doing further research.

Discussion

Determining the decision-making factors for patients choosing between graft types for ACL reconstruction is important to ensure that patients can make a decision based on objective information. Several previous studies have evaluated patient selection of ACL grafts.^8-10 All 3 of these studies showed that surgeon recommendation is the primary factor in a patient’s decision. Similar to previous studies, we also found that physician recommendation is the most influential factor involved in this decision.

At an average follow-up of 41 months, Cohen and colleagues⁸ found that 1.3% of patients did not know whether they received an autograft or allograft for their ACL reconstruction. Furthermore, 50.7% of patients stating they received an allograft in Cohen’s study⁸ were unsure of the harvest location. In our study, 4% of patients at their first postoperative visit did not know whether they had received an autograft or allograft and 10% of patients stating they received an allograft selected an unknown harvest site. In contrast, only 2% of autograft patients in our study were unsure of the harvest location at their first postoperative appointment. It is likely that, over time, patients with an allograft forget the harvest location, whereas autograft patients are more likely to remember the location of harvest. This is especially true in patients with anterior knee pain or hamstring pain following ACL reconstruction with a BPTB or hamstring tendon autograft, respectively.

In terms of patients’ knowledge of their graft type, we found an overall accuracy of 77%, with 88% of autograft patients, 71% of allograft patients, and 11% of hybrid graft patients remembering their graft type and harvest location. Although we do not believe it to be critical for patients to remember these details, we do believe that patients who do not know their graft type likely relied on the recommendation of their physician.

We found a significant difference in the proportion of patients choosing autograft vs allograft based on surgeon, despite these surgeons citing available data in the literature to each patient and ultimately allowing each patient to make his or her own decision. This is partly due to the low sample size of most of the surgeons involved. However, the main reason for this distortion is likely that different surgeons may highlight different aspects of the literature to “spin” patients towards one graft or another in certain cases.

Currently, there remains a lack of clarity in the literature on appropriate ACL graft choices for patients. With constant new findings being published on different aspects of various grafts, it is important for surgeons to remain up to date with the literature. Nevertheless, we believe that certain biases are inevitable among surgeons due to unique training experiences as well as experience with their own patients.

Cohen and colleagues8 found that only 7% of patients reported that their own personal research influenced their decision, and only 6.4% of patients reported the media as their primary decision-making factor. Cheung and colleagues⁹ conducted a retrospective study and found that more than half of patients did significant personal research prior to making a decision regarding their graft type. Most of this research was done using medical websites and literature. Koh and colleagues¹⁰ noted that >80% of patients consulted the internet for graft information before making a decision. Koh’s study¹⁰ was performed in Korea and therefore the high prevalence of internet use may be culturally-related.

Overall, quality of information for patients undergoing ACL reconstruction is mixed across the internet, with only 22.5% of top websites being affiliated with an academic institution and 35.5% of websites authored by private physicians or physician groups.¹¹ Although a majority of internet websites offer discussion into the condition and surgical procedure of ACL reconstruction, less than half of these websites share the equally important information on the eligibility for surgery and concomitant complications following surgery.¹¹In our study, only 39 patients (13%) listed the media as either the first (13, 4%) or second (26, 9%) most important factor in their graft decision. Clearly there is some discrepancy between studies regarding the influence of personal research and media. There are a few potential reasons for this. First, we did not explicitly ask patients if their own personal research had any influence on their graft decision. Rather, we asked patients to rank their decision-making factors, and few patients ranked the media as their first or second greatest influence. Second, the word “media” was used in our questionnaire rather than “online research” or “internet.” It may seem somewhat vague to patients what the word “media” really means in terms of their own research, whereas listing “online research” or “internet” as selection options may have influenced patient responses.

In our study, we asked patients for any additional factors that influenced their graft choice. Thirteen patients (4%) noted that “personal research” through internet, orthopaedic literature, and the media influenced their graft decision. This corroborates the idea that “media” may have seemed vague to some patients. Of these patients, 9 chose an autograft and 4 chose an allograft. The relative ease in accessing information regarding graft choice in ACL reconstruction should be noted. Numerous websites offer advice, graft options, and commentary from group practices and orthopaedic surgeons. Whether or not these sources provide reasonable support for one graft vs another graft remains to be answered. The physician should be responsible for providing the patient with this collected objective information.

In our study, 205 patients (96%) were satisfied with their graft choice at the time of follow-up, with 15 patients (7%) stating that they would have chosen a different graft type if they could redo the operation. Cheung and colleagues⁹ found a satisfaction rate of 87.4% at an average follow-up time of 19 months, with 4.6% stating they would have chosen a different graft type. Many factors can contribute to patient satisfaction after ACL reconstruction. Looking at patient variables such as age, demographics, occupation, activity level, surgical technique including tunnel placement and fixation, postoperative rehabilitation, and graft type may influence the success of the patient after ACL reconstruction.

The strengths of this study include the patient population size with 1-year follow-up as well as the prospective study design. In comparison to a previous retrospective study in 2009 by Cohen and colleagues⁸with a sample size of 240 patients, our study collected 213 patients with 70% follow-up at minimum 1 year. Collecting data prospectively ensures accurate representation of the factors influencing each patient’s graft selection, while follow-up data was useful for patient satisfaction.

The limitations of this study include the percentage of patients lost from follow-up as well as any bias generated from the organization of the questionnaire. Unfortunately, with a younger, transient population of patients undergoing ACL reconstruction in a major metropolitan area, a percentage of patients are lost to follow-up. Many attempts were made to locate these patients. Another potential limitation was the order of decision factors listed on the questionnaire. These factors were not ordered randomly on each survey, but were listed in the following order: (1) physician recommendation (2) family/friend’s recommendation (3) coach’s recommendation and (4) the media. This may have influenced patient responses. The organization of these factors in the questionnaire started with physician recommendation, which may have influenced the patient’s initial thought process of which factor had the greatest influence in their graft decision. In addition, for the surveys completed at least 1 year following surgery, some patients were contacted via e-mail and others via telephone. Thus, some patients may have changed their answers if they were able to see the questions rather than hearing the questions. We believe this is particularly true of the question regarding graft harvest site.

Our study indicates that the majority of patients undergoing ACL reconstruction are primarily influenced by the physician’s recommendation.

Anterior cruciate ligament (ACL) injuries affect >175,000 people each year,¹ with >100,000 Americans undergoing ACL reconstruction annually.² Due to the high impact this injury has on the general population, and especially on athletes, it is important to determine the factors that influence a patient’s selection of a particular graft type. With increasing access to information and other outside influences, surgeons should attempt to provide as much objective information as possible in order to allow patients to make appropriate informed decisions regarding their graft choice for ACL surgery.

While autografts are used in >60% of primary ACL reconstructions, allografts are used in >80% of revision procedures.³ Both autografts and allografts offer advantages and disadvantages, and the advantages of each may depend on patient age, activity level, and occupation.⁴ For example, graft rerupture rates have been shown to be higher in patients with ACL allografts⁴, while kneeling pain has been shown to be worse in patients with bone-patellar tendon-bone (BPTB) autografts compared to hamstring autografts⁵ as well as BPTB allografts.⁴

Patient satisfaction rates are high for ACL autografts and allografts. Boonriong and Kietsiriroje⁶ have shown visual analog scale (VAS) patient satisfaction score averages to be 88 out of 100 for BPTB autografts and 93 out of 100 for hamstring tendon autografts. Fox and colleagues⁷ showed that 87% of patients were completely or mostly satisfied following revision ACL reconstruction with patellar tendon allograft. Cohen and colleagues⁸ evaluated 240 patients undergoing primary ACL reconstruction; 63.3% underwent ACL reconstruction with an allograft and 35.4% with an autograft. Of all patients enrolled in the study, 93% were satisfied with their graft choice, with 12.7% of patients opting to choose another graft if in the same situation again. Of those patients, 63.3% would have switched from an autograft to allograft. Although these numbers represent high patient satisfaction following a variety of ACL graft types, it is important to continue to identify graft selection factors in order to maximize patient outcomes.

The purposes of this prospective study were to assess patients’ knowledge of their graft type used for ACL reconstruction, to determine the most influential factors involved in graft selection, and to determine the level of satisfaction with the graft of choice at a minimum of 1-year follow-up. Based on a previous retrospective study,8 we hypothesized that physician recommendation would be the most influential factor in ACL graft selection. We also hypothesized that patients receiving an autograft would be more accurate in stating their graft harvest location compared to allograft patients.

Materials and Methods

We prospectively enrolled 304 patients who underwent primary ACL reconstruction from January 2008 to September 2013. Surgery was performed by 9 different surgeons within the same practice. All patients undergoing primary ACL reconstruction were eligible for the study.

All surgeons explained to each patient the pros and cons of each graft choice based upon peer-reviewed literature. Each patient was allowed to choose autograft or allograft, although most of the surgeons strongly encourage patients under age 25 years to choose autograft. One of the surgeons specifically encourages a patellar tendon autograft in patients under age 30 to 35 years, except for those patients with a narrow patellar tendon on magnetic resonance imaging, in which case he recommends a hamstring autograft. Another surgeon also specifically encourages patellar tendon autograft in patients under 35 years, except in skeletally immature patients, for whom he encourages hamstring autograft. However, none of the surgeons prohibited patients from choosing autograft or allograft, regardless of age.

The Institutional Review Board at our institution provided approval for this study. At the first postoperative follow-up appointment, each patient completed a questionnaire asking to select from a list the type (“your own” or “a cadaver”) and harvest site of the graft that was used for the surgery. Patients were also asked how they decided upon that graft type by ranking a list of 4 factors from 1 to 4. These included (1) physician recommendation, (2) family/friend’s recommendation, (3) coach’s recommendation, and (4) the media. Patients had the option of ranking more than one factor as most important in their decision. In addition, patients were asked to list any other factors that influenced their decision regarding graft type.

At a minimum of 1 year following surgery, patients completed the same questionnaire described above. In addition, patients were asked if they were satisfied with their graft and whether they would choose the same graft type if undergoing ACL reconstruction again. Patients who would have chosen a different graft were asked which graft they would have chosen and why. Any patient who experienced graft rupture prior to follow-up was included in the analysis.

Statistical Analysis

Chi square tests were used to compare dichotomous outcomes. A type I error of less than 5% (P < .05) was considered statistically significant.

Results

At least 1 year following ACL reconstruction, 213 of 304 patients (70%) successfully completed the same questionnaire as they did at their first postoperative follow-up appointment. The mean age of these patients at the time of surgery was 31.9 ± 11.0 years (range, 13.9 to 58.0 years). The mean follow-up time was 1.4 ± 0.4 years (range, 1.0 to 2.6 years), and 59% of these patients were male.

Autografts were used for 139 patients (139/304, 46%), allografts for 156 patients (156/304, 51%), and hybrid grafts for 9 patients (9/304, 3%). Overall, 77% of patients were accurate in stating the type of graft used for their ACL reconstruction, including 88% of autograft patients, 71% of allograft patients, and 11% of hybrid graft patients (Table 1). Patients who underwent reconstruction with an autograft were significantly more accurate in stating their graft type compared to patients with an allograft (P < .001). Graft type by surgeon is shown in Table 2. A statistically significant difference was found in the proportion of patients choosing autograft versus allograft based on surgeon (P < .0001).

When asked which type of graft was used for their surgery, 12 of 304 patients (4%) did not know their graft type or harvest location. Twenty-nine patients stated that their graft was an allograft but did not know the harvest location. Five patients stated that their graft was an autograft but did not know the harvest location. The 34 patients who classified their choice of graft but did not know the harvest site (11%) stated their surgeon never told them where their graft was from or they did not remember. A complete list of graft type responses is shown in Table 3.

Of the 29 patients who stated that their graft was an allograft but did not know the harvest location, 19 (66%) had a tibialis anterior allograft, 7 (24%) had a BPTB allograft, 2 (7%) had an Achilles tendon allograft, and 1 (3%) had a tibialis anterior autograft.

Physician recommendation was the most important decision-making factor listed for 82% of patients at their first postoperative appointment (Table 4). In addition to the 4 factors listed on our survey, patients were allowed to write in other factors involved in their decision. The most popular answers included recovery time, personal research on graft types, and prior personal experience with ACL reconstruction on the contralateral knee.

At the time of 1-year follow-up, 205 of 213 patients (96%) said they were satisfied with their graft choice (Table 5). All 4 unsatisfied autograft patients received a hamstring autograft, 3 of which were performed by the same surgeon. No significant difference was found in satisfaction rates between patients with autograft vs allograft (P = .87). There was a higher satisfaction rate among patients with a BPTB autograft compared to those with a hamstring autograft (P = .043). Of the unsatisfied patients, 3 patients stated that their graft had failed in the time prior to follow-up and 2 patients stated that they were having donor site pain following surgery with hamstring autograft and would consider an allograft if the reconstruction were repeated (Table 6). Two patients stated that they were unsatisfied with their graft but would need to do more research before deciding on a different graft type.

As shown in Tables 5 and 6, there is a discrepancy between the number of patients who were unsatisfied with their graft and the number of patients who stated that they would switch to a different graft type if they were to have ACL reconstruction again. A number of patients stated that they were satisfied with their graft, yet they would switch to a different graft. The main reasons for this related to issues from a hamstring autograft harvest site. One patient noted that although she was satisfied with her graft, she would switch after doing further research.

Discussion

Determining the decision-making factors for patients choosing between graft types for ACL reconstruction is important to ensure that patients can make a decision based on objective information. Several previous studies have evaluated patient selection of ACL grafts.^8-10 All 3 of these studies showed that surgeon recommendation is the primary factor in a patient’s decision. Similar to previous studies, we also found that physician recommendation is the most influential factor involved in this decision.

At an average follow-up of 41 months, Cohen and colleagues⁸ found that 1.3% of patients did not know whether they received an autograft or allograft for their ACL reconstruction. Furthermore, 50.7% of patients stating they received an allograft in Cohen’s study⁸ were unsure of the harvest location. In our study, 4% of patients at their first postoperative visit did not know whether they had received an autograft or allograft and 10% of patients stating they received an allograft selected an unknown harvest site. In contrast, only 2% of autograft patients in our study were unsure of the harvest location at their first postoperative appointment. It is likely that, over time, patients with an allograft forget the harvest location, whereas autograft patients are more likely to remember the location of harvest. This is especially true in patients with anterior knee pain or hamstring pain following ACL reconstruction with a BPTB or hamstring tendon autograft, respectively.

In terms of patients’ knowledge of their graft type, we found an overall accuracy of 77%, with 88% of autograft patients, 71% of allograft patients, and 11% of hybrid graft patients remembering their graft type and harvest location. Although we do not believe it to be critical for patients to remember these details, we do believe that patients who do not know their graft type likely relied on the recommendation of their physician.

We found a significant difference in the proportion of patients choosing autograft vs allograft based on surgeon, despite these surgeons citing available data in the literature to each patient and ultimately allowing each patient to make his or her own decision. This is partly due to the low sample size of most of the surgeons involved. However, the main reason for this distortion is likely that different surgeons may highlight different aspects of the literature to “spin” patients towards one graft or another in certain cases.

Currently, there remains a lack of clarity in the literature on appropriate ACL graft choices for patients. With constant new findings being published on different aspects of various grafts, it is important for surgeons to remain up to date with the literature. Nevertheless, we believe that certain biases are inevitable among surgeons due to unique training experiences as well as experience with their own patients.

Cohen and colleagues8 found that only 7% of patients reported that their own personal research influenced their decision, and only 6.4% of patients reported the media as their primary decision-making factor. Cheung and colleagues⁹ conducted a retrospective study and found that more than half of patients did significant personal research prior to making a decision regarding their graft type. Most of this research was done using medical websites and literature. Koh and colleagues¹⁰ noted that >80% of patients consulted the internet for graft information before making a decision. Koh’s study¹⁰ was performed in Korea and therefore the high prevalence of internet use may be culturally-related.

Overall, quality of information for patients undergoing ACL reconstruction is mixed across the internet, with only 22.5% of top websites being affiliated with an academic institution and 35.5% of websites authored by private physicians or physician groups.¹¹ Although a majority of internet websites offer discussion into the condition and surgical procedure of ACL reconstruction, less than half of these websites share the equally important information on the eligibility for surgery and concomitant complications following surgery.¹¹In our study, only 39 patients (13%) listed the media as either the first (13, 4%) or second (26, 9%) most important factor in their graft decision. Clearly there is some discrepancy between studies regarding the influence of personal research and media. There are a few potential reasons for this. First, we did not explicitly ask patients if their own personal research had any influence on their graft decision. Rather, we asked patients to rank their decision-making factors, and few patients ranked the media as their first or second greatest influence. Second, the word “media” was used in our questionnaire rather than “online research” or “internet.” It may seem somewhat vague to patients what the word “media” really means in terms of their own research, whereas listing “online research” or “internet” as selection options may have influenced patient responses.

In our study, we asked patients for any additional factors that influenced their graft choice. Thirteen patients (4%) noted that “personal research” through internet, orthopaedic literature, and the media influenced their graft decision. This corroborates the idea that “media” may have seemed vague to some patients. Of these patients, 9 chose an autograft and 4 chose an allograft. The relative ease in accessing information regarding graft choice in ACL reconstruction should be noted. Numerous websites offer advice, graft options, and commentary from group practices and orthopaedic surgeons. Whether or not these sources provide reasonable support for one graft vs another graft remains to be answered. The physician should be responsible for providing the patient with this collected objective information.

In our study, 205 patients (96%) were satisfied with their graft choice at the time of follow-up, with 15 patients (7%) stating that they would have chosen a different graft type if they could redo the operation. Cheung and colleagues⁹ found a satisfaction rate of 87.4% at an average follow-up time of 19 months, with 4.6% stating they would have chosen a different graft type. Many factors can contribute to patient satisfaction after ACL reconstruction. Looking at patient variables such as age, demographics, occupation, activity level, surgical technique including tunnel placement and fixation, postoperative rehabilitation, and graft type may influence the success of the patient after ACL reconstruction.

The strengths of this study include the patient population size with 1-year follow-up as well as the prospective study design. In comparison to a previous retrospective study in 2009 by Cohen and colleagues⁸with a sample size of 240 patients, our study collected 213 patients with 70% follow-up at minimum 1 year. Collecting data prospectively ensures accurate representation of the factors influencing each patient’s graft selection, while follow-up data was useful for patient satisfaction.

The limitations of this study include the percentage of patients lost from follow-up as well as any bias generated from the organization of the questionnaire. Unfortunately, with a younger, transient population of patients undergoing ACL reconstruction in a major metropolitan area, a percentage of patients are lost to follow-up. Many attempts were made to locate these patients. Another potential limitation was the order of decision factors listed on the questionnaire. These factors were not ordered randomly on each survey, but were listed in the following order: (1) physician recommendation (2) family/friend’s recommendation (3) coach’s recommendation and (4) the media. This may have influenced patient responses. The organization of these factors in the questionnaire started with physician recommendation, which may have influenced the patient’s initial thought process of which factor had the greatest influence in their graft decision. In addition, for the surveys completed at least 1 year following surgery, some patients were contacted via e-mail and others via telephone. Thus, some patients may have changed their answers if they were able to see the questions rather than hearing the questions. We believe this is particularly true of the question regarding graft harvest site.

Our study indicates that the majority of patients undergoing ACL reconstruction are primarily influenced by the physician’s recommendation.

Anterior cruciate ligament (ACL) injuries affect >175,000 people each year,¹ with >100,000 Americans undergoing ACL reconstruction annually.² Due to the high impact this injury has on the general population, and especially on athletes, it is important to determine the factors that influence a patient’s selection of a particular graft type. With increasing access to information and other outside influences, surgeons should attempt to provide as much objective information as possible in order to allow patients to make appropriate informed decisions regarding their graft choice for ACL surgery.

While autografts are used in >60% of primary ACL reconstructions, allografts are used in >80% of revision procedures.³ Both autografts and allografts offer advantages and disadvantages, and the advantages of each may depend on patient age, activity level, and occupation.⁴ For example, graft rerupture rates have been shown to be higher in patients with ACL allografts⁴, while kneeling pain has been shown to be worse in patients with bone-patellar tendon-bone (BPTB) autografts compared to hamstring autografts⁵ as well as BPTB allografts.⁴

Patient satisfaction rates are high for ACL autografts and allografts. Boonriong and Kietsiriroje⁶ have shown visual analog scale (VAS) patient satisfaction score averages to be 88 out of 100 for BPTB autografts and 93 out of 100 for hamstring tendon autografts. Fox and colleagues⁷ showed that 87% of patients were completely or mostly satisfied following revision ACL reconstruction with patellar tendon allograft. Cohen and colleagues⁸ evaluated 240 patients undergoing primary ACL reconstruction; 63.3% underwent ACL reconstruction with an allograft and 35.4% with an autograft. Of all patients enrolled in the study, 93% were satisfied with their graft choice, with 12.7% of patients opting to choose another graft if in the same situation again. Of those patients, 63.3% would have switched from an autograft to allograft. Although these numbers represent high patient satisfaction following a variety of ACL graft types, it is important to continue to identify graft selection factors in order to maximize patient outcomes.

The purposes of this prospective study were to assess patients’ knowledge of their graft type used for ACL reconstruction, to determine the most influential factors involved in graft selection, and to determine the level of satisfaction with the graft of choice at a minimum of 1-year follow-up. Based on a previous retrospective study,8 we hypothesized that physician recommendation would be the most influential factor in ACL graft selection. We also hypothesized that patients receiving an autograft would be more accurate in stating their graft harvest location compared to allograft patients.

Materials and Methods

We prospectively enrolled 304 patients who underwent primary ACL reconstruction from January 2008 to September 2013. Surgery was performed by 9 different surgeons within the same practice. All patients undergoing primary ACL reconstruction were eligible for the study.

All surgeons explained to each patient the pros and cons of each graft choice based upon peer-reviewed literature. Each patient was allowed to choose autograft or allograft, although most of the surgeons strongly encourage patients under age 25 years to choose autograft. One of the surgeons specifically encourages a patellar tendon autograft in patients under age 30 to 35 years, except for those patients with a narrow patellar tendon on magnetic resonance imaging, in which case he recommends a hamstring autograft. Another surgeon also specifically encourages patellar tendon autograft in patients under 35 years, except in skeletally immature patients, for whom he encourages hamstring autograft. However, none of the surgeons prohibited patients from choosing autograft or allograft, regardless of age.

The Institutional Review Board at our institution provided approval for this study. At the first postoperative follow-up appointment, each patient completed a questionnaire asking to select from a list the type (“your own” or “a cadaver”) and harvest site of the graft that was used for the surgery. Patients were also asked how they decided upon that graft type by ranking a list of 4 factors from 1 to 4. These included (1) physician recommendation, (2) family/friend’s recommendation, (3) coach’s recommendation, and (4) the media. Patients had the option of ranking more than one factor as most important in their decision. In addition, patients were asked to list any other factors that influenced their decision regarding graft type.

At a minimum of 1 year following surgery, patients completed the same questionnaire described above. In addition, patients were asked if they were satisfied with their graft and whether they would choose the same graft type if undergoing ACL reconstruction again. Patients who would have chosen a different graft were asked which graft they would have chosen and why. Any patient who experienced graft rupture prior to follow-up was included in the analysis.

Statistical Analysis

Chi square tests were used to compare dichotomous outcomes. A type I error of less than 5% (P < .05) was considered statistically significant.

Results

At least 1 year following ACL reconstruction, 213 of 304 patients (70%) successfully completed the same questionnaire as they did at their first postoperative follow-up appointment. The mean age of these patients at the time of surgery was 31.9 ± 11.0 years (range, 13.9 to 58.0 years). The mean follow-up time was 1.4 ± 0.4 years (range, 1.0 to 2.6 years), and 59% of these patients were male.

Autografts were used for 139 patients (139/304, 46%), allografts for 156 patients (156/304, 51%), and hybrid grafts for 9 patients (9/304, 3%). Overall, 77% of patients were accurate in stating the type of graft used for their ACL reconstruction, including 88% of autograft patients, 71% of allograft patients, and 11% of hybrid graft patients (Table 1). Patients who underwent reconstruction with an autograft were significantly more accurate in stating their graft type compared to patients with an allograft (P < .001). Graft type by surgeon is shown in Table 2. A statistically significant difference was found in the proportion of patients choosing autograft versus allograft based on surgeon (P < .0001).

When asked which type of graft was used for their surgery, 12 of 304 patients (4%) did not know their graft type or harvest location. Twenty-nine patients stated that their graft was an allograft but did not know the harvest location. Five patients stated that their graft was an autograft but did not know the harvest location. The 34 patients who classified their choice of graft but did not know the harvest site (11%) stated their surgeon never told them where their graft was from or they did not remember. A complete list of graft type responses is shown in Table 3.

Of the 29 patients who stated that their graft was an allograft but did not know the harvest location, 19 (66%) had a tibialis anterior allograft, 7 (24%) had a BPTB allograft, 2 (7%) had an Achilles tendon allograft, and 1 (3%) had a tibialis anterior autograft.

Physician recommendation was the most important decision-making factor listed for 82% of patients at their first postoperative appointment (Table 4). In addition to the 4 factors listed on our survey, patients were allowed to write in other factors involved in their decision. The most popular answers included recovery time, personal research on graft types, and prior personal experience with ACL reconstruction on the contralateral knee.

At the time of 1-year follow-up, 205 of 213 patients (96%) said they were satisfied with their graft choice (Table 5). All 4 unsatisfied autograft patients received a hamstring autograft, 3 of which were performed by the same surgeon. No significant difference was found in satisfaction rates between patients with autograft vs allograft (P = .87). There was a higher satisfaction rate among patients with a BPTB autograft compared to those with a hamstring autograft (P = .043). Of the unsatisfied patients, 3 patients stated that their graft had failed in the time prior to follow-up and 2 patients stated that they were having donor site pain following surgery with hamstring autograft and would consider an allograft if the reconstruction were repeated (Table 6). Two patients stated that they were unsatisfied with their graft but would need to do more research before deciding on a different graft type.

As shown in Tables 5 and 6, there is a discrepancy between the number of patients who were unsatisfied with their graft and the number of patients who stated that they would switch to a different graft type if they were to have ACL reconstruction again. A number of patients stated that they were satisfied with their graft, yet they would switch to a different graft. The main reasons for this related to issues from a hamstring autograft harvest site. One patient noted that although she was satisfied with her graft, she would switch after doing further research.

Discussion

Determining the decision-making factors for patients choosing between graft types for ACL reconstruction is important to ensure that patients can make a decision based on objective information. Several previous studies have evaluated patient selection of ACL grafts.^8-10 All 3 of these studies showed that surgeon recommendation is the primary factor in a patient’s decision. Similar to previous studies, we also found that physician recommendation is the most influential factor involved in this decision.

At an average follow-up of 41 months, Cohen and colleagues⁸ found that 1.3% of patients did not know whether they received an autograft or allograft for their ACL reconstruction. Furthermore, 50.7% of patients stating they received an allograft in Cohen’s study⁸ were unsure of the harvest location. In our study, 4% of patients at their first postoperative visit did not know whether they had received an autograft or allograft and 10% of patients stating they received an allograft selected an unknown harvest site. In contrast, only 2% of autograft patients in our study were unsure of the harvest location at their first postoperative appointment. It is likely that, over time, patients with an allograft forget the harvest location, whereas autograft patients are more likely to remember the location of harvest. This is especially true in patients with anterior knee pain or hamstring pain following ACL reconstruction with a BPTB or hamstring tendon autograft, respectively.

In terms of patients’ knowledge of their graft type, we found an overall accuracy of 77%, with 88% of autograft patients, 71% of allograft patients, and 11% of hybrid graft patients remembering their graft type and harvest location. Although we do not believe it to be critical for patients to remember these details, we do believe that patients who do not know their graft type likely relied on the recommendation of their physician.

We found a significant difference in the proportion of patients choosing autograft vs allograft based on surgeon, despite these surgeons citing available data in the literature to each patient and ultimately allowing each patient to make his or her own decision. This is partly due to the low sample size of most of the surgeons involved. However, the main reason for this distortion is likely that different surgeons may highlight different aspects of the literature to “spin” patients towards one graft or another in certain cases.

Currently, there remains a lack of clarity in the literature on appropriate ACL graft choices for patients. With constant new findings being published on different aspects of various grafts, it is important for surgeons to remain up to date with the literature. Nevertheless, we believe that certain biases are inevitable among surgeons due to unique training experiences as well as experience with their own patients.

Cohen and colleagues8 found that only 7% of patients reported that their own personal research influenced their decision, and only 6.4% of patients reported the media as their primary decision-making factor. Cheung and colleagues⁹ conducted a retrospective study and found that more than half of patients did significant personal research prior to making a decision regarding their graft type. Most of this research was done using medical websites and literature. Koh and colleagues¹⁰ noted that >80% of patients consulted the internet for graft information before making a decision. Koh’s study¹⁰ was performed in Korea and therefore the high prevalence of internet use may be culturally-related.

Overall, quality of information for patients undergoing ACL reconstruction is mixed across the internet, with only 22.5% of top websites being affiliated with an academic institution and 35.5% of websites authored by private physicians or physician groups.¹¹ Although a majority of internet websites offer discussion into the condition and surgical procedure of ACL reconstruction, less than half of these websites share the equally important information on the eligibility for surgery and concomitant complications following surgery.¹¹In our study, only 39 patients (13%) listed the media as either the first (13, 4%) or second (26, 9%) most important factor in their graft decision. Clearly there is some discrepancy between studies regarding the influence of personal research and media. There are a few potential reasons for this. First, we did not explicitly ask patients if their own personal research had any influence on their graft decision. Rather, we asked patients to rank their decision-making factors, and few patients ranked the media as their first or second greatest influence. Second, the word “media” was used in our questionnaire rather than “online research” or “internet.” It may seem somewhat vague to patients what the word “media” really means in terms of their own research, whereas listing “online research” or “internet” as selection options may have influenced patient responses.

In our study, we asked patients for any additional factors that influenced their graft choice. Thirteen patients (4%) noted that “personal research” through internet, orthopaedic literature, and the media influenced their graft decision. This corroborates the idea that “media” may have seemed vague to some patients. Of these patients, 9 chose an autograft and 4 chose an allograft. The relative ease in accessing information regarding graft choice in ACL reconstruction should be noted. Numerous websites offer advice, graft options, and commentary from group practices and orthopaedic surgeons. Whether or not these sources provide reasonable support for one graft vs another graft remains to be answered. The physician should be responsible for providing the patient with this collected objective information.

In our study, 205 patients (96%) were satisfied with their graft choice at the time of follow-up, with 15 patients (7%) stating that they would have chosen a different graft type if they could redo the operation. Cheung and colleagues⁹ found a satisfaction rate of 87.4% at an average follow-up time of 19 months, with 4.6% stating they would have chosen a different graft type. Many factors can contribute to patient satisfaction after ACL reconstruction. Looking at patient variables such as age, demographics, occupation, activity level, surgical technique including tunnel placement and fixation, postoperative rehabilitation, and graft type may influence the success of the patient after ACL reconstruction.

The strengths of this study include the patient population size with 1-year follow-up as well as the prospective study design. In comparison to a previous retrospective study in 2009 by Cohen and colleagues⁸with a sample size of 240 patients, our study collected 213 patients with 70% follow-up at minimum 1 year. Collecting data prospectively ensures accurate representation of the factors influencing each patient’s graft selection, while follow-up data was useful for patient satisfaction.

The limitations of this study include the percentage of patients lost from follow-up as well as any bias generated from the organization of the questionnaire. Unfortunately, with a younger, transient population of patients undergoing ACL reconstruction in a major metropolitan area, a percentage of patients are lost to follow-up. Many attempts were made to locate these patients. Another potential limitation was the order of decision factors listed on the questionnaire. These factors were not ordered randomly on each survey, but were listed in the following order: (1) physician recommendation (2) family/friend’s recommendation (3) coach’s recommendation and (4) the media. This may have influenced patient responses. The organization of these factors in the questionnaire started with physician recommendation, which may have influenced the patient’s initial thought process of which factor had the greatest influence in their graft decision. In addition, for the surveys completed at least 1 year following surgery, some patients were contacted via e-mail and others via telephone. Thus, some patients may have changed their answers if they were able to see the questions rather than hearing the questions. We believe this is particularly true of the question regarding graft harvest site.

Our study indicates that the majority of patients undergoing ACL reconstruction are primarily influenced by the physician’s recommendation.

Rheumatoid arthritis (RA) commonly affects the hand and fingers, most often at the metacarpophalangeal and proximal interphalangeal (PIP) joints. Synovitis, tendon ruptures, Boutonnière and swan-neck deformities, and joint destruction often occur. Bony ankylosis is not commonly described yet frequently occurs in patients with RA.¹

Implant arthroplasty is an established treatment for arthritis of the hand and fingers. Indications for its use include RA, osteoarthritis, and posttraumatic arthritis. Most patients treated with implant arthroplasty can expect pain relief and 40° to 65° of PIP joint motion.^2,3 Silicone arthroplasty historically has been used for pain relief but not for restoration of motion in an ankylosed joint. To our knowledge, there are no reports of using implant arthroplasty in the treatment of spontaneous ankylosis in RA. Contraindications for this procedure would include infection, irreparable flexor or extensor apparatus, and severe medical comorbidities.

In this article, we report a case of PIP joint autofusion treated with silicone PIP arthroplasty in a patient with RA. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 56-year-old woman who had had RA for more than 20 years underwent left carpometacarpal arthroplasty and thumb reconstruction. She subsequently presented with complaints of progressively worsening functioning of the left ring and small fingers. On initial evaluation, her PIP joints were fused in about 15° of flexion. Radiographs (Figures 1A, 1B) showed severe diffuse arthritis of the hands and complete bony ankylosis of the ring- and small-finger PIP joints with radial deviation of the ring-finger middle phalanx. The patient had minimal pain but wanted improved hand motion and opted for takedown of the ankylosis with silicone PIP joint arthroplasty.

Radial dorsal incisions were made over the PIP joints of the ring and small fingers. As is not the case with arthroplasty for routine PIP joint arthritis, presence of bony ankylosis made identification of the native PIP joint more difficult. The transverse retinacular ligament was identified and opened, and the collateral ligament, which was not ankylosed, was dissected off the proximal phalanx. These landmarks were useful in locating the PIP joint, and proper positioning was confirmed with fluoroscopy. The ankylosed joint space was opened with an osteotome, and about 8 to 10 mm of bone was resected to create space for the instrumentation. As the amount of scarring within the flexor tendon sheath was not significant, restoration of motion did not require extensive tenolysis. The extensor mechanism was slightly contracted, but the bony resection allowed flexion to be restored. The distal portion of the proximal phalanx was then resected. The proximal and middle phalanges were reamed, and a silicone prosthesis was placed with the finger held straight. The collateral ligament was repaired back to the proximal phalanx with 4-0 polydioxanone sutures placed through a bone tunnel created with a Kirschner wire. The skin was closed with 4-0 nylon, and a postoperative splint was applied.

The initial postoperative course was unremarkable. The patient was immobilized in 10° of PIP joint flexion for 10 days, and therapy was initiated after the splint was removed. Twenty-four months after surgery, the patient was pain-free and had 60° of active PIP joint flexion, with extensor lag of only 10°. Clinically, alignment of the fingers was satisfactory; there was mild persistent radial deviation of 10° to 15° (Figures 2A, 2B). Radiographs showed good positioning of the implants (Figures 3A, 3B) and no sign of coronal instability. The patient was satisfied with her improved functioning and returned to employment as a hospital clerk, working full-time.

Discussion

RA of the hand and fingers can be painful and disabling. Although there are several treatment options for many of the most common manifestations, options are limited for bony ankylosis of the finger joints. The patient described in this case report had minimal pain, but the loss of motion of the PIP joints in her ring and small fingers created difficulties for her at work. She wanted surgery that would improve the functioning of her fingers. PIP joint arthroplasty traditionally has been the treatment of choice for PIP joint arthritis. In 1985, Swanson and colleagues² reported on more than 400 silicone PIP arthroplasties performed over 16 years. Mean range of motion (ROM) was between 45° and 60°, with 70% of patients having ROM of more than 40°. Pain relief was complete in 98% of cases. Complications included implant fracture (5%) and recurrent or new deformities (6.5%). A 10.9% revision rate was noted at minimum 1-year follow-up. Recent implants made of improved biomaterials hold promise, but longer term follow-up is still needed.

Silicone arthroplasty has also been used as an effective treatment for non-RA of the PIP joint. Bales and colleagues⁴ reviewed long-term results of silicone arthroplasty for PIP joint osteoarthritis in 22 patients. At a mean of 10 years, mean QuickDASH (Disabilities of the Arm, Shoulder, and Hand) score was 17, mean visual analog scale score for pain was 0.4, and implant survivorship was 90%. Despite unchanged ROM and considerable implant deformation or fracture, patients’ pain relief and satisfaction were consistent.

Hage and colleagues⁵ reviewed long-term results of silicone PIP arthroplasty for posttraumatic arthritis in 14 patients. Most of the patients were satisfied: Although they had notable rotational deformity, alignment deviation, and loss of pinch strength and ROM, they were pain-free. The authors concluded that silicone arthroplasty should be used for posttraumatic arthrosis cases in which associated adhesions may be corrected with simple tenolysis, and even in these cases the objective results may not be as good as the subjective outcome.

Kaye⁶ used radiographs to determine the incidence of bony ankylosis in 203 patients with RA. Hand and wrist radiographs of 48 (23.6%) of these patients showed ankylosis, and 34 of the 48 patients had 2 or more joints fused. On a questionnaire, patients with ankylosis indicated more difficulty with activities of daily living and more limited activity. The authors concluded that radiographic bony ankylosis was a relatively common feature of RA and a marker of disease that was clinically, radiographically, and functionally more severe.

The patient described in this case report had a satisfactory result after PIP joint arthroplasty. At 2-year follow-up, she remained pain-free, and her previously ankylosed PIP joint had an arc of motion of 10° to 60°. Most patients with bony ankylosis of PIP joints present with minimal pain and do not seek surgical treatment. However, patients with ankylosis that limits functioning or activities of daily living may wish to pursue intervention that could be restorative. PIP joint arthroplasty may be effective in improving motion in patients with bony ankylosis of the finger joints.

Rheumatoid arthritis (RA) commonly affects the hand and fingers, most often at the metacarpophalangeal and proximal interphalangeal (PIP) joints. Synovitis, tendon ruptures, Boutonnière and swan-neck deformities, and joint destruction often occur. Bony ankylosis is not commonly described yet frequently occurs in patients with RA.¹

Implant arthroplasty is an established treatment for arthritis of the hand and fingers. Indications for its use include RA, osteoarthritis, and posttraumatic arthritis. Most patients treated with implant arthroplasty can expect pain relief and 40° to 65° of PIP joint motion.^2,3 Silicone arthroplasty historically has been used for pain relief but not for restoration of motion in an ankylosed joint. To our knowledge, there are no reports of using implant arthroplasty in the treatment of spontaneous ankylosis in RA. Contraindications for this procedure would include infection, irreparable flexor or extensor apparatus, and severe medical comorbidities.

In this article, we report a case of PIP joint autofusion treated with silicone PIP arthroplasty in a patient with RA. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 56-year-old woman who had had RA for more than 20 years underwent left carpometacarpal arthroplasty and thumb reconstruction. She subsequently presented with complaints of progressively worsening functioning of the left ring and small fingers. On initial evaluation, her PIP joints were fused in about 15° of flexion. Radiographs (Figures 1A, 1B) showed severe diffuse arthritis of the hands and complete bony ankylosis of the ring- and small-finger PIP joints with radial deviation of the ring-finger middle phalanx. The patient had minimal pain but wanted improved hand motion and opted for takedown of the ankylosis with silicone PIP joint arthroplasty.

Radial dorsal incisions were made over the PIP joints of the ring and small fingers. As is not the case with arthroplasty for routine PIP joint arthritis, presence of bony ankylosis made identification of the native PIP joint more difficult. The transverse retinacular ligament was identified and opened, and the collateral ligament, which was not ankylosed, was dissected off the proximal phalanx. These landmarks were useful in locating the PIP joint, and proper positioning was confirmed with fluoroscopy. The ankylosed joint space was opened with an osteotome, and about 8 to 10 mm of bone was resected to create space for the instrumentation. As the amount of scarring within the flexor tendon sheath was not significant, restoration of motion did not require extensive tenolysis. The extensor mechanism was slightly contracted, but the bony resection allowed flexion to be restored. The distal portion of the proximal phalanx was then resected. The proximal and middle phalanges were reamed, and a silicone prosthesis was placed with the finger held straight. The collateral ligament was repaired back to the proximal phalanx with 4-0 polydioxanone sutures placed through a bone tunnel created with a Kirschner wire. The skin was closed with 4-0 nylon, and a postoperative splint was applied.

The initial postoperative course was unremarkable. The patient was immobilized in 10° of PIP joint flexion for 10 days, and therapy was initiated after the splint was removed. Twenty-four months after surgery, the patient was pain-free and had 60° of active PIP joint flexion, with extensor lag of only 10°. Clinically, alignment of the fingers was satisfactory; there was mild persistent radial deviation of 10° to 15° (Figures 2A, 2B). Radiographs showed good positioning of the implants (Figures 3A, 3B) and no sign of coronal instability. The patient was satisfied with her improved functioning and returned to employment as a hospital clerk, working full-time.

Discussion

RA of the hand and fingers can be painful and disabling. Although there are several treatment options for many of the most common manifestations, options are limited for bony ankylosis of the finger joints. The patient described in this case report had minimal pain, but the loss of motion of the PIP joints in her ring and small fingers created difficulties for her at work. She wanted surgery that would improve the functioning of her fingers. PIP joint arthroplasty traditionally has been the treatment of choice for PIP joint arthritis. In 1985, Swanson and colleagues² reported on more than 400 silicone PIP arthroplasties performed over 16 years. Mean range of motion (ROM) was between 45° and 60°, with 70% of patients having ROM of more than 40°. Pain relief was complete in 98% of cases. Complications included implant fracture (5%) and recurrent or new deformities (6.5%). A 10.9% revision rate was noted at minimum 1-year follow-up. Recent implants made of improved biomaterials hold promise, but longer term follow-up is still needed.

Silicone arthroplasty has also been used as an effective treatment for non-RA of the PIP joint. Bales and colleagues⁴ reviewed long-term results of silicone arthroplasty for PIP joint osteoarthritis in 22 patients. At a mean of 10 years, mean QuickDASH (Disabilities of the Arm, Shoulder, and Hand) score was 17, mean visual analog scale score for pain was 0.4, and implant survivorship was 90%. Despite unchanged ROM and considerable implant deformation or fracture, patients’ pain relief and satisfaction were consistent.

Hage and colleagues⁵ reviewed long-term results of silicone PIP arthroplasty for posttraumatic arthritis in 14 patients. Most of the patients were satisfied: Although they had notable rotational deformity, alignment deviation, and loss of pinch strength and ROM, they were pain-free. The authors concluded that silicone arthroplasty should be used for posttraumatic arthrosis cases in which associated adhesions may be corrected with simple tenolysis, and even in these cases the objective results may not be as good as the subjective outcome.

Kaye⁶ used radiographs to determine the incidence of bony ankylosis in 203 patients with RA. Hand and wrist radiographs of 48 (23.6%) of these patients showed ankylosis, and 34 of the 48 patients had 2 or more joints fused. On a questionnaire, patients with ankylosis indicated more difficulty with activities of daily living and more limited activity. The authors concluded that radiographic bony ankylosis was a relatively common feature of RA and a marker of disease that was clinically, radiographically, and functionally more severe.

The patient described in this case report had a satisfactory result after PIP joint arthroplasty. At 2-year follow-up, she remained pain-free, and her previously ankylosed PIP joint had an arc of motion of 10° to 60°. Most patients with bony ankylosis of PIP joints present with minimal pain and do not seek surgical treatment. However, patients with ankylosis that limits functioning or activities of daily living may wish to pursue intervention that could be restorative. PIP joint arthroplasty may be effective in improving motion in patients with bony ankylosis of the finger joints.

Rheumatoid arthritis (RA) commonly affects the hand and fingers, most often at the metacarpophalangeal and proximal interphalangeal (PIP) joints. Synovitis, tendon ruptures, Boutonnière and swan-neck deformities, and joint destruction often occur. Bony ankylosis is not commonly described yet frequently occurs in patients with RA.¹

Implant arthroplasty is an established treatment for arthritis of the hand and fingers. Indications for its use include RA, osteoarthritis, and posttraumatic arthritis. Most patients treated with implant arthroplasty can expect pain relief and 40° to 65° of PIP joint motion.^2,3 Silicone arthroplasty historically has been used for pain relief but not for restoration of motion in an ankylosed joint. To our knowledge, there are no reports of using implant arthroplasty in the treatment of spontaneous ankylosis in RA. Contraindications for this procedure would include infection, irreparable flexor or extensor apparatus, and severe medical comorbidities.

In this article, we report a case of PIP joint autofusion treated with silicone PIP arthroplasty in a patient with RA. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 56-year-old woman who had had RA for more than 20 years underwent left carpometacarpal arthroplasty and thumb reconstruction. She subsequently presented with complaints of progressively worsening functioning of the left ring and small fingers. On initial evaluation, her PIP joints were fused in about 15° of flexion. Radiographs (Figures 1A, 1B) showed severe diffuse arthritis of the hands and complete bony ankylosis of the ring- and small-finger PIP joints with radial deviation of the ring-finger middle phalanx. The patient had minimal pain but wanted improved hand motion and opted for takedown of the ankylosis with silicone PIP joint arthroplasty.

Radial dorsal incisions were made over the PIP joints of the ring and small fingers. As is not the case with arthroplasty for routine PIP joint arthritis, presence of bony ankylosis made identification of the native PIP joint more difficult. The transverse retinacular ligament was identified and opened, and the collateral ligament, which was not ankylosed, was dissected off the proximal phalanx. These landmarks were useful in locating the PIP joint, and proper positioning was confirmed with fluoroscopy. The ankylosed joint space was opened with an osteotome, and about 8 to 10 mm of bone was resected to create space for the instrumentation. As the amount of scarring within the flexor tendon sheath was not significant, restoration of motion did not require extensive tenolysis. The extensor mechanism was slightly contracted, but the bony resection allowed flexion to be restored. The distal portion of the proximal phalanx was then resected. The proximal and middle phalanges were reamed, and a silicone prosthesis was placed with the finger held straight. The collateral ligament was repaired back to the proximal phalanx with 4-0 polydioxanone sutures placed through a bone tunnel created with a Kirschner wire. The skin was closed with 4-0 nylon, and a postoperative splint was applied.

The initial postoperative course was unremarkable. The patient was immobilized in 10° of PIP joint flexion for 10 days, and therapy was initiated after the splint was removed. Twenty-four months after surgery, the patient was pain-free and had 60° of active PIP joint flexion, with extensor lag of only 10°. Clinically, alignment of the fingers was satisfactory; there was mild persistent radial deviation of 10° to 15° (Figures 2A, 2B). Radiographs showed good positioning of the implants (Figures 3A, 3B) and no sign of coronal instability. The patient was satisfied with her improved functioning and returned to employment as a hospital clerk, working full-time.

Discussion

RA of the hand and fingers can be painful and disabling. Although there are several treatment options for many of the most common manifestations, options are limited for bony ankylosis of the finger joints. The patient described in this case report had minimal pain, but the loss of motion of the PIP joints in her ring and small fingers created difficulties for her at work. She wanted surgery that would improve the functioning of her fingers. PIP joint arthroplasty traditionally has been the treatment of choice for PIP joint arthritis. In 1985, Swanson and colleagues² reported on more than 400 silicone PIP arthroplasties performed over 16 years. Mean range of motion (ROM) was between 45° and 60°, with 70% of patients having ROM of more than 40°. Pain relief was complete in 98% of cases. Complications included implant fracture (5%) and recurrent or new deformities (6.5%). A 10.9% revision rate was noted at minimum 1-year follow-up. Recent implants made of improved biomaterials hold promise, but longer term follow-up is still needed.

Silicone arthroplasty has also been used as an effective treatment for non-RA of the PIP joint. Bales and colleagues⁴ reviewed long-term results of silicone arthroplasty for PIP joint osteoarthritis in 22 patients. At a mean of 10 years, mean QuickDASH (Disabilities of the Arm, Shoulder, and Hand) score was 17, mean visual analog scale score for pain was 0.4, and implant survivorship was 90%. Despite unchanged ROM and considerable implant deformation or fracture, patients’ pain relief and satisfaction were consistent.

Hage and colleagues⁵ reviewed long-term results of silicone PIP arthroplasty for posttraumatic arthritis in 14 patients. Most of the patients were satisfied: Although they had notable rotational deformity, alignment deviation, and loss of pinch strength and ROM, they were pain-free. The authors concluded that silicone arthroplasty should be used for posttraumatic arthrosis cases in which associated adhesions may be corrected with simple tenolysis, and even in these cases the objective results may not be as good as the subjective outcome.

Kaye⁶ used radiographs to determine the incidence of bony ankylosis in 203 patients with RA. Hand and wrist radiographs of 48 (23.6%) of these patients showed ankylosis, and 34 of the 48 patients had 2 or more joints fused. On a questionnaire, patients with ankylosis indicated more difficulty with activities of daily living and more limited activity. The authors concluded that radiographic bony ankylosis was a relatively common feature of RA and a marker of disease that was clinically, radiographically, and functionally more severe.

The patient described in this case report had a satisfactory result after PIP joint arthroplasty. At 2-year follow-up, she remained pain-free, and her previously ankylosed PIP joint had an arc of motion of 10° to 60°. Most patients with bony ankylosis of PIP joints present with minimal pain and do not seek surgical treatment. However, patients with ankylosis that limits functioning or activities of daily living may wish to pursue intervention that could be restorative. PIP joint arthroplasty may be effective in improving motion in patients with bony ankylosis of the finger joints.

Patients who receive a peripheral nerve block during hip or knee replacement surgery are less likely to experience complications, according to a recent large retrospective study.

Researchers reviewed more than 1 million hip and knee replacements performed between 2006 and 2013 using data from approximately 3,000 hospitals in the United States.

Investigators compiled information on cardiac, pulmonary, gastrointestinal, and renal complications. They also determined the rate of infections, wound complications, and inpatient falls. In addition, they analyzed data on resource utilization, which included the number of blood transfusions needed, admission to an intensive care unit, opioid consumption, length of hospital stay, and the cost of hospitalization.

They looked at data for 342,726 patients who had hip replacement surgery and 719,426 who had knee replacement surgery.

Overall, 18% of the patients received a peripheral nerve block. They found the rate peripheral nerve block use among patients with knee replacement increased from 15.2% in 2006 to 24.5% in 2013. The use of peripheral nerve blocks was associated with significantly lower odds for almost all complications.

A strong effect was seen for cardiac complications in patients with knee replacement and for wound complications in people who had hip replacement. Similar patterns were observed for resource utilization, particularly in length of hospital stay among patients with hip replacement.

Patients who receive a peripheral nerve block during hip or knee replacement surgery are less likely to experience complications, according to a recent large retrospective study.

Researchers reviewed more than 1 million hip and knee replacements performed between 2006 and 2013 using data from approximately 3,000 hospitals in the United States.

Investigators compiled information on cardiac, pulmonary, gastrointestinal, and renal complications. They also determined the rate of infections, wound complications, and inpatient falls. In addition, they analyzed data on resource utilization, which included the number of blood transfusions needed, admission to an intensive care unit, opioid consumption, length of hospital stay, and the cost of hospitalization.

They looked at data for 342,726 patients who had hip replacement surgery and 719,426 who had knee replacement surgery.

Overall, 18% of the patients received a peripheral nerve block. They found the rate peripheral nerve block use among patients with knee replacement increased from 15.2% in 2006 to 24.5% in 2013. The use of peripheral nerve blocks was associated with significantly lower odds for almost all complications.

A strong effect was seen for cardiac complications in patients with knee replacement and for wound complications in people who had hip replacement. Similar patterns were observed for resource utilization, particularly in length of hospital stay among patients with hip replacement.

Patients who receive a peripheral nerve block during hip or knee replacement surgery are less likely to experience complications, according to a recent large retrospective study.

Researchers reviewed more than 1 million hip and knee replacements performed between 2006 and 2013 using data from approximately 3,000 hospitals in the United States.

Investigators compiled information on cardiac, pulmonary, gastrointestinal, and renal complications. They also determined the rate of infections, wound complications, and inpatient falls. In addition, they analyzed data on resource utilization, which included the number of blood transfusions needed, admission to an intensive care unit, opioid consumption, length of hospital stay, and the cost of hospitalization.

They looked at data for 342,726 patients who had hip replacement surgery and 719,426 who had knee replacement surgery.

Overall, 18% of the patients received a peripheral nerve block. They found the rate peripheral nerve block use among patients with knee replacement increased from 15.2% in 2006 to 24.5% in 2013. The use of peripheral nerve blocks was associated with significantly lower odds for almost all complications.

A strong effect was seen for cardiac complications in patients with knee replacement and for wound complications in people who had hip replacement. Similar patterns were observed for resource utilization, particularly in length of hospital stay among patients with hip replacement.