Knee

ABSTRACT

The purpose of this study is to describe the rate of return to the operating room (OR) following microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and osteochondral allograft (OCA) procedures at 90 days, 1 year, and 2 years. Current Procedural Terminology codes for all patients undergoing MFX, ACI, OATS, and OCA were used to search a prospectively collected, commercially available private payer insurance company database from 2007 to 2011. Within 90 days, 1 year, and 2 years after surgery, the database was searched for the occurrence of these same patients undergoing knee diagnostic arthroscopy with biopsy, lysis of adhesions, synovectomy, arthroscopy for infection or lavage, arthroscopy for removal of loose bodies, chondroplasty, MFX, ACI, OATS, OCA, and/or knee arthroplasty. Descriptive statistical analysis and contingency table analysis were performed. A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX, 640 ACI, 386 open OATS, 997 arthroscopic OATS, 714 open OCA, and 894 arthroscopic OCA procedures. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. At 2 years, patients who underwent MFX, ACI, OATS, OCA had reoperation rates of 14.65%, 29.69%, 8.82%, and 12.22%, respectively. There was a statistically significantly increased risk for ACI return to OR within all intervals (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative treatment options. With a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

Continue to: Symptomatic, full-thickness articular cartilage

Symptomatic, full-thickness articular cartilage defects in the knee are difficult to manage, particularly in the young, athletic patient population. Fortunately, a variety of cartilage repair (direct repair of the cartilage or those procedures which attempt to generate fibrocartilage) and restoration (those aimed at restoring hyaline cartilage) procedures are available, with encouraging short- and long-term clinical outcomes. After failure of nonoperative management, several surgical options are available for treating symptomatic focal chondral defects, including microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and open and arthroscopic osteochondral allograft (OCA) transplantation procedures.^1,2 When appropriately indicated, each of these techniques has demonstrated good to excellent clinical outcomes with respect to reducing pain and improving function.^3-5

While major complications following cartilage surgery are uncommon, the need for reoperation following an index articular cartilage operation is poorly understood. Recently, McCormick and colleagues6 found that reoperation within the first 2 years following meniscus allograft transplantation (MAT) is associated with an increased likelihood of revision MAT or future arthroplasty. Given the association between early reoperation following meniscus restoration surgery and subsequent failure, an improved understanding of the epidemiology and implications of reoperations following cartilage restoration surgery is warranted. Further, in deciding which treatment option is best suited to a particular patient, the rate of return to the operating room (OR) should be taken into consideration, as this could potentially influence surgical decision-making as to which procedure to perform, especially in value-based care decision-making environments.

The purpose of this study is to describe the rate of return to the OR for knee procedures following cartilage restoration at intervals of 90 days, 1 year, and 2 years across a large-scale US patient database. The authors hypothesize that the rate of return to the OR following knee cartilage repair or restoration procedures will be under 20% during the first post-operative year, with increasing reoperation rates over time. A secondary hypothesis is that there will be no difference in reoperation rates according to sex, but that younger patients (those younger than 40 years) will have higher reoperation rates than older patients.

METHODS

We performed a retrospective analysis of a prospectively collected, large-scale, and commercially available private payer insurance company database (PearlDiver) from 2007 to 2011. The PearlDiver database is a Health Insurance Portability and Accountability Act (HIPAA) compliant, publicly available national database consisting of a collection of private payer records, with United Health Group representing the contributing health plan. The database has more than 30 million patient records and contains Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) codes related to orthopedic procedures. From 2007 to 2011, the private payer database captured between 5.9 million and 6.2 million patients per year.

Our search was based on the CPT codes for MFX (29879), ACI (27412), OATS (29866, 29867), and OCA (27415, 27416). Return to the OR for revision surgery for the above-mentioned procedures was classified as patients with a diagnosis of diagnostic arthroscopy with biopsy (CPT 29870), lysis of adhesions (CPT 29884), synovectomy (29875, 29876), arthroscopy for infection or lavage (CPT 29871), arthroscopy for removal of loose bodies (29874), chondroplasty (29877), unicompartmental knee arthroplasty (27446), total knee arthroplasty (27447), and/or patellar arthroplasty (27438). Patient records were followed for reoperations occurring within 90 days, 1 year, and 2 years after the index cartilage procedure. All data were compared based on patient age and sex.

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analysis of this study was primarily descriptive to demonstrate the incidence for each code at each time interval. One-way analysis of variance, Chi-square analysis, and contingency tables were used to compare the incidence of each type of procedure throughout the various time intervals. A P-value of < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS v.20 (International Business Machines).

RESULTS

A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX (92.3%) 640 ACI (1.4%), 386 open OATS (0.82%), 997 arthroscopic OATS (2.11%), 714 open OCA (1.51%), and 894 arthroscopic OCA (1.89%) procedures. A summary of the procedures performed, broken down by age and sex, is provided in Tables 1 and 2. A total of 25,149 male patients (53.3%) underwent surgical procedures compared to 22,058 female patients (46.7%). For each category of procedure (MFX, ACI, OATS, OCA), there was a significantly higher proportion of males than females undergoing surgery (P < .0001 for all). Surgical treatment with MFX was consistently the most frequently performed surgery across all age groups (92.31%), while cell-based therapy with ACI was the least frequently performed procedure across all age ranges (1.36%). Restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not utilized in patients over 64 years of age (Table 2).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

A summary of all reoperation data is provided in Tables 3 to 7 and Figures 1 and 2. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. Patients who underwent MFX had reoperation rates of 6.05% at 90 days, 11.80% at 1 year, and 14.65% at 2 years. Patients who underwent ACI had reoperation rates of 4.53% at 90 days, 23.28% at 1 year, and 29.69% at 2 years. Patients who had open and arthroscopic OATS had reoperation rates of 3.122% and 5.12% at 90 days, 6.74% and 8.53% at 1 year, and 7.51% and 10.13% at 2 years, respectively. Patients who underwent open and arthroscopic OCA had reoperation rates of 2.52% and 3.91% at 90 days, 7.14% and 6.60% at 1 year, and 13.59% and 10.85% at 2 years (Table 3). There was a statistically significantly increased risk for reoperation following ACI within all intervals compared to all other surgical techniques (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty at 6.70%. There was no significant difference between failure rates (revision OATS/OCA or conversion to arthroplasty) between the restorative treatment options, with 14 failures for OATS (9.52% of reoperations at 2 years) compared to 22 failures for OCA (12.7% of reoperations at 2 years, P = .358). Among the entire cohort of cartilage surgery patients, arthroscopic chondroplasty was the most frequent procedure performed at the time of reoperation at all time points assessed, notably accounting for 33.08% of reoperations 2 years following microfracture, 51.58% of reoperations at 2 years following ACI, 53.06% of reoperations at 2 years following OATS, and 54.07% of reoperations at 2 years following OCA (Figure 3, Tables 4–7).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; MFX, microfracture; OR, operating room.

^aA -1 denotes No. <11 within the PearlDiver database, and exact numbers are not reported due to patient privacy considerations.

Abbreviations: ACI, autologous chondrocyte implantation; CPT, Current Procedural Terminology; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OCA, osteochondral allograft; OR, operating room.

Continue to: Discussion...

DISCUSSION

The principle findings of this study demonstrate that there is an overall reoperation rate of 14.90% at 2 years following cartilage repair/restoration surgery, with the highest reoperation rates following MFX at 90 days, and ACI at both 1 year and 2 years following the index procedure. Also, patients undergoing index MFX as the index procedure have the highest risk for conversion to arthroplasty, reoperation rates for all cartilage surgeries increase over time, and arthroscopic chondroplasty is the most frequent procedure performed at the time of reoperation.

The management of symptomatic articular cartilage knee pathology is extremely challenging. With improvements in surgical technique, instrumentation, and clinical decision-making, indications are constantly evolving. Techniques that may work for “small” defects, though there is some debate as to what constitutes a “small” defect, are not necessarily going to be successful for larger defects, and this certainly varies depending on where the defect is located within the knee joint (distal femur vs patella vs trochlea, etc.). Recently, in a 2015 analysis of 3 level I or II studies, Miller and colleagues⁷ demonstrated both MFX and OATS to be viable, cost-effective, first-line treatment options for articular cartilage injuries, with similar clinical outcomes at 8.7 years. The authors noted cumulative reoperation rates of 29% among patients undergoing MFX compared to 13% among patients undergoing OATS. While ACI and OCA procedures were not included in their study, the reported reoperation rates of 29% following MFX and 13% following OATS at nearly 10 years suggest a possible increased need for reoperation following MFX over time (approximately 15% at 2 years in our study) and a stable rate of reoperation following OATS (approximately 11% at 2 years in our study). This finding is significant, as one of the goals with these procedures is to deliver effective, long-lasting pain relief and restoration of function. Interestingly, in this study, restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not performed in patients older than 64 years. This may be explained by the higher prevalence of acute traumatic injuries and osteochondritis dissecans diagnoses in younger patients compared with older patients, as these diagnoses are more often indicated to undergo restorative procedures as opposed to marrow stimulation.

In a 2016 systematic review of 20 studies incorporating 1117 patients, Campbell and colleagues⁸ assessed return-to-play rates following MFX, ACI, OATS, and OCA. The authors noted that return to sport (RTS) rates were greatest following OATS (89%), followed by OCA (88%), ACI (84%), and MFX (75%). Positive prognostic factors for RTS included younger age, shorter duration of preoperative symptoms, no history of prior ipsilateral knee surgery, and smaller chondral defects. Reoperation rates between the 4 techniques were not statistically compared in their study. Interestingly, in 2013, Chalmers and colleagues⁹ conducted a separate systematic review of 20 studies comprising 1375 patients undergoing MFX, ACI, or OATS. In their study, the authors found significant advantages following ACI and OATS compared to MFX with respect to patient-reported outcome scores but noted significantly faster RTS rates with MFX. Reoperation rates were noted to be similar between the 3 procedures (25% for ACI, 21% for MFX, and 28% for OATS) at an average 3.7 years following the index procedure. When considering these 2 systematic reviews together, despite a faster RTS rate following MFX, a greater proportion of patients seem to be able to RTS over time following other procedures such as OATS, OCA, and ACI. Unfortunately, these reviews do not provide insight as to the role, if any, of reoperation on return to play rates nor on overall clinical outcome scores on patients undergoing articular cartilage surgery. However, this information is valuable when counseling athletes who are in season and would like to RTS as soon as possible as opposed to those who do not have tight time constraints for when they need to RTS.

Regardless of the cartilage technique chosen, the goals of surgery remain similar—to reduce pain and improve function. For athletes, the ultimate goal is to return to the same level of play that the athlete was able to achieve prior to injury. Certainly, the need for reoperation following a cartilage surgery has implications on pain, function, and ability to RTS. Our review of nearly 50,000 cartilage surgeries demonstrates that reoperations following cartilage repair surgery are not uncommon, with a rate of 14.90% at 2 years, and that while reoperation rates are the highest following ACI, the rate of conversion to knee arthroplasty is highest following MFX. Due to the limitations of the PearlDiver database, it is not possible to determine the clinical outcomes of patients undergoing reoperation following cartilage surgery, but certainly, given these data, reoperation is clearly not necessarily indicative of clinical failure. This is highlighted by the fact that the most common procedure performed at the time of reoperation is arthroscopic chondroplasty, which, despite being an additional surgical procedure, may be acceptable for patients who wish to RTS, particularly in the setting of an index ACI in which there may be graft hypertrophy. Ideally, additional studies incorporating a cost-effectiveness analysis of each of the procedures, incorporating reoperation rates as well as patient-reported clinical outcomes, would be helpful to truly determine the patient and societal implications of reoperation following cartilage repair/restoration.

Many of the advantages and disadvantages of the described cartilage repair/restoration procedures have been well described.^10-17 Microfracture is the most commonly utilized first-line repair/restoration option for small articular cartilage lesions, mainly due to its low cost, low morbidity, and relatively low level of difficulty.18 Despite these advantages, MFX is not without limitations, and the need for revision cartilage restoration and/or conversion to arthroplasty is concerning. In 2013, Salzmann and colleagues19 evaluated a cohort of 454 patients undergoing MFX for a symptomatic knee defect and noted a reoperation rate of 26.9% (n = 123) within 2 years of the index surgery, with risk factors for reoperation noted to include an increased number of pre-MFX ipsilateral knee surgeries, patellofemoral lesions, smoking, and lower preoperative numeric analog scale scores. The definition of reoperation in their study is unfortunately not described, and thus the extent of reoperation (arthroscopy to arthroplasty) is unclear. In a 2009 systematic review of 3122 patients (28 studies) undergoing MFX conducted by Mithoefer and colleagues,²⁰ revision rates were noted to range from 2% to 31% depending on the study analyzed, with increasing revision rates after 2 years. Unfortunately, the heterogeneity of the included studies makes it difficult to determine which patients tend to fail over time.

Continue to: OATS...

OATS is a promising cartilage restoration technique indicated for treatment of patients with large, uncontained chondral lesions, and/or lesions with both bone and cartilage loss.¹ OCA is similar to OATS but uses allograft tissue instead of autograft tissue and is typically considered a viable treatment option in larger lesions (>2 cm²).²¹ Cell-based ACI therapy has evolved substantially over the past decade and is now available as a third-generation model utilizing biodegradable 3-dimensional scaffolds seeded with chondrocytes. Reoperation rates following ACI can often be higher than those following other cartilage treatments, particularly given the known complication of graft hypertrophy and/or delamination. Harris and colleagues²² conducted a systematic review of 5276 subjects undergoing ACI (all generations), noting an overall reoperation rate of 33%, but a failure rate of 5.8% at an average of 22 months following ACI. Risk factors for reoperation included periosteal-based ACI as well as open (vs arthroscopic) ACI. In this study, we found a modestly lower return to OR rate of 29.69% at 2 years.

When the outcomes of patients undergoing OATS or OCA are compared to those of patients undergoing MFX or ACI, it can be difficult to interpret the results, as the indications for performing these procedures tend to be very different. Further, the reasons for reoperation, as well as the procedures performed at the time of reoperation, are often poorly described, making it difficult to truly quantify the risk of reoperation and the implications of reoperation for patients undergoing any of these index cartilage procedures.

Overall, in this database, the return to the OR rate approaches 15% at 2 years following cartilage surgery, with cell-based therapy demonstrating higher reoperation rates at 2 years, without the risk of conversion to arthroplasty. Reoperation rates appear to stabilize at 1 year following surgery and consist mostly of minor arthroscopic procedures. These findings can help surgeons counsel patients as to the rate and type of reoperations that can be expected following cartilage surgery. Additional research incorporating patient-reported outcomes and patient-specific risk factors are needed to complement these data as to the impact of reoperations on overall clinical outcomes. Further, studies incorporating 90-day, 1-year, and 2-year costs associated with cartilage surgery will help to determine which index procedure is the most cost effective over the short- and long-term.

LIMITATIONS

This study is not without limitations. The PearlDiver database is reliant upon accurate CPT and ICD-9 coding, which creates a potential for a reporting bias. The overall reliability of the analyses is dependent on the quality of the available data, which, as noted in previous PearlDiver studies,^18,23-28 may include inaccurate billing codes, miscoding, and/or non-coding by physicians as potential sources of error. At the time of this study, the PearlDiver database did not provide consistent data points on laterality, and thus it is possible that the reported rates of reoperation overestimate the true reoperation rate following a given procedure. Fortunately, the reoperation rates for each procedure analyzed in this database study are consistent with those previously presented in the literature. In addition, it is not uncommon for patients receiving one of these procedures to have previously been treated with one of the others. Due to the inherent limitations of the PearlDiver database, this study did not investigate concomitant procedures performed along with the index procedure, nor did it investigate confounding factors such as comorbidities. The PearlDiver database does not provide data on defect size, location within the knee, concomitant pathologies (eg, meniscus tear), prior surgeries, or patient comorbidities, and while important, these factors cannot be accounted for in our analysis. The inability to account for these important factors, particularly concomitant diagnoses, procedures, and lesion size/location, represents an important limitation of this study, as this is a source of selection bias and may influence the need for reoperation in a given patient. Despite these limitations, the results of this study are supported by previous and current literature. In addition, the PearlDiver database, as a HIPAA-compliant database, does not report exact numbers when the value of the outcome of interest is between 0 and 10, which prohibits analysis of any cartilage procedure performed in a cohort of patients greater than 1 and less than 11. Finally, while not necessarily a limitation, it should be noted that CPT 29879 is not specific for microfracture, as the code also includes abrasion arthroplasty and drilling. Due to the limitations of the methodology of searching the database for this code, it is unclear as to how many patients underwent actual microfracture vs abrasion arthroplasty.

CONCLUSION

Within a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference between failure/revision rates among the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

ABSTRACT

The purpose of this study is to describe the rate of return to the operating room (OR) following microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and osteochondral allograft (OCA) procedures at 90 days, 1 year, and 2 years. Current Procedural Terminology codes for all patients undergoing MFX, ACI, OATS, and OCA were used to search a prospectively collected, commercially available private payer insurance company database from 2007 to 2011. Within 90 days, 1 year, and 2 years after surgery, the database was searched for the occurrence of these same patients undergoing knee diagnostic arthroscopy with biopsy, lysis of adhesions, synovectomy, arthroscopy for infection or lavage, arthroscopy for removal of loose bodies, chondroplasty, MFX, ACI, OATS, OCA, and/or knee arthroplasty. Descriptive statistical analysis and contingency table analysis were performed. A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX, 640 ACI, 386 open OATS, 997 arthroscopic OATS, 714 open OCA, and 894 arthroscopic OCA procedures. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. At 2 years, patients who underwent MFX, ACI, OATS, OCA had reoperation rates of 14.65%, 29.69%, 8.82%, and 12.22%, respectively. There was a statistically significantly increased risk for ACI return to OR within all intervals (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative treatment options. With a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

Continue to: Symptomatic, full-thickness articular cartilage

Symptomatic, full-thickness articular cartilage defects in the knee are difficult to manage, particularly in the young, athletic patient population. Fortunately, a variety of cartilage repair (direct repair of the cartilage or those procedures which attempt to generate fibrocartilage) and restoration (those aimed at restoring hyaline cartilage) procedures are available, with encouraging short- and long-term clinical outcomes. After failure of nonoperative management, several surgical options are available for treating symptomatic focal chondral defects, including microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and open and arthroscopic osteochondral allograft (OCA) transplantation procedures.^1,2 When appropriately indicated, each of these techniques has demonstrated good to excellent clinical outcomes with respect to reducing pain and improving function.^3-5

While major complications following cartilage surgery are uncommon, the need for reoperation following an index articular cartilage operation is poorly understood. Recently, McCormick and colleagues6 found that reoperation within the first 2 years following meniscus allograft transplantation (MAT) is associated with an increased likelihood of revision MAT or future arthroplasty. Given the association between early reoperation following meniscus restoration surgery and subsequent failure, an improved understanding of the epidemiology and implications of reoperations following cartilage restoration surgery is warranted. Further, in deciding which treatment option is best suited to a particular patient, the rate of return to the operating room (OR) should be taken into consideration, as this could potentially influence surgical decision-making as to which procedure to perform, especially in value-based care decision-making environments.

The purpose of this study is to describe the rate of return to the OR for knee procedures following cartilage restoration at intervals of 90 days, 1 year, and 2 years across a large-scale US patient database. The authors hypothesize that the rate of return to the OR following knee cartilage repair or restoration procedures will be under 20% during the first post-operative year, with increasing reoperation rates over time. A secondary hypothesis is that there will be no difference in reoperation rates according to sex, but that younger patients (those younger than 40 years) will have higher reoperation rates than older patients.

METHODS

We performed a retrospective analysis of a prospectively collected, large-scale, and commercially available private payer insurance company database (PearlDiver) from 2007 to 2011. The PearlDiver database is a Health Insurance Portability and Accountability Act (HIPAA) compliant, publicly available national database consisting of a collection of private payer records, with United Health Group representing the contributing health plan. The database has more than 30 million patient records and contains Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) codes related to orthopedic procedures. From 2007 to 2011, the private payer database captured between 5.9 million and 6.2 million patients per year.

Our search was based on the CPT codes for MFX (29879), ACI (27412), OATS (29866, 29867), and OCA (27415, 27416). Return to the OR for revision surgery for the above-mentioned procedures was classified as patients with a diagnosis of diagnostic arthroscopy with biopsy (CPT 29870), lysis of adhesions (CPT 29884), synovectomy (29875, 29876), arthroscopy for infection or lavage (CPT 29871), arthroscopy for removal of loose bodies (29874), chondroplasty (29877), unicompartmental knee arthroplasty (27446), total knee arthroplasty (27447), and/or patellar arthroplasty (27438). Patient records were followed for reoperations occurring within 90 days, 1 year, and 2 years after the index cartilage procedure. All data were compared based on patient age and sex.

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analysis of this study was primarily descriptive to demonstrate the incidence for each code at each time interval. One-way analysis of variance, Chi-square analysis, and contingency tables were used to compare the incidence of each type of procedure throughout the various time intervals. A P-value of < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS v.20 (International Business Machines).

RESULTS

A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX (92.3%) 640 ACI (1.4%), 386 open OATS (0.82%), 997 arthroscopic OATS (2.11%), 714 open OCA (1.51%), and 894 arthroscopic OCA (1.89%) procedures. A summary of the procedures performed, broken down by age and sex, is provided in Tables 1 and 2. A total of 25,149 male patients (53.3%) underwent surgical procedures compared to 22,058 female patients (46.7%). For each category of procedure (MFX, ACI, OATS, OCA), there was a significantly higher proportion of males than females undergoing surgery (P < .0001 for all). Surgical treatment with MFX was consistently the most frequently performed surgery across all age groups (92.31%), while cell-based therapy with ACI was the least frequently performed procedure across all age ranges (1.36%). Restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not utilized in patients over 64 years of age (Table 2).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

A summary of all reoperation data is provided in Tables 3 to 7 and Figures 1 and 2. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. Patients who underwent MFX had reoperation rates of 6.05% at 90 days, 11.80% at 1 year, and 14.65% at 2 years. Patients who underwent ACI had reoperation rates of 4.53% at 90 days, 23.28% at 1 year, and 29.69% at 2 years. Patients who had open and arthroscopic OATS had reoperation rates of 3.122% and 5.12% at 90 days, 6.74% and 8.53% at 1 year, and 7.51% and 10.13% at 2 years, respectively. Patients who underwent open and arthroscopic OCA had reoperation rates of 2.52% and 3.91% at 90 days, 7.14% and 6.60% at 1 year, and 13.59% and 10.85% at 2 years (Table 3). There was a statistically significantly increased risk for reoperation following ACI within all intervals compared to all other surgical techniques (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty at 6.70%. There was no significant difference between failure rates (revision OATS/OCA or conversion to arthroplasty) between the restorative treatment options, with 14 failures for OATS (9.52% of reoperations at 2 years) compared to 22 failures for OCA (12.7% of reoperations at 2 years, P = .358). Among the entire cohort of cartilage surgery patients, arthroscopic chondroplasty was the most frequent procedure performed at the time of reoperation at all time points assessed, notably accounting for 33.08% of reoperations 2 years following microfracture, 51.58% of reoperations at 2 years following ACI, 53.06% of reoperations at 2 years following OATS, and 54.07% of reoperations at 2 years following OCA (Figure 3, Tables 4–7).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; MFX, microfracture; OR, operating room.

^aA -1 denotes No. <11 within the PearlDiver database, and exact numbers are not reported due to patient privacy considerations.

Abbreviations: ACI, autologous chondrocyte implantation; CPT, Current Procedural Terminology; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OCA, osteochondral allograft; OR, operating room.

Continue to: Discussion...

DISCUSSION

The principle findings of this study demonstrate that there is an overall reoperation rate of 14.90% at 2 years following cartilage repair/restoration surgery, with the highest reoperation rates following MFX at 90 days, and ACI at both 1 year and 2 years following the index procedure. Also, patients undergoing index MFX as the index procedure have the highest risk for conversion to arthroplasty, reoperation rates for all cartilage surgeries increase over time, and arthroscopic chondroplasty is the most frequent procedure performed at the time of reoperation.

The management of symptomatic articular cartilage knee pathology is extremely challenging. With improvements in surgical technique, instrumentation, and clinical decision-making, indications are constantly evolving. Techniques that may work for “small” defects, though there is some debate as to what constitutes a “small” defect, are not necessarily going to be successful for larger defects, and this certainly varies depending on where the defect is located within the knee joint (distal femur vs patella vs trochlea, etc.). Recently, in a 2015 analysis of 3 level I or II studies, Miller and colleagues⁷ demonstrated both MFX and OATS to be viable, cost-effective, first-line treatment options for articular cartilage injuries, with similar clinical outcomes at 8.7 years. The authors noted cumulative reoperation rates of 29% among patients undergoing MFX compared to 13% among patients undergoing OATS. While ACI and OCA procedures were not included in their study, the reported reoperation rates of 29% following MFX and 13% following OATS at nearly 10 years suggest a possible increased need for reoperation following MFX over time (approximately 15% at 2 years in our study) and a stable rate of reoperation following OATS (approximately 11% at 2 years in our study). This finding is significant, as one of the goals with these procedures is to deliver effective, long-lasting pain relief and restoration of function. Interestingly, in this study, restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not performed in patients older than 64 years. This may be explained by the higher prevalence of acute traumatic injuries and osteochondritis dissecans diagnoses in younger patients compared with older patients, as these diagnoses are more often indicated to undergo restorative procedures as opposed to marrow stimulation.

In a 2016 systematic review of 20 studies incorporating 1117 patients, Campbell and colleagues⁸ assessed return-to-play rates following MFX, ACI, OATS, and OCA. The authors noted that return to sport (RTS) rates were greatest following OATS (89%), followed by OCA (88%), ACI (84%), and MFX (75%). Positive prognostic factors for RTS included younger age, shorter duration of preoperative symptoms, no history of prior ipsilateral knee surgery, and smaller chondral defects. Reoperation rates between the 4 techniques were not statistically compared in their study. Interestingly, in 2013, Chalmers and colleagues⁹ conducted a separate systematic review of 20 studies comprising 1375 patients undergoing MFX, ACI, or OATS. In their study, the authors found significant advantages following ACI and OATS compared to MFX with respect to patient-reported outcome scores but noted significantly faster RTS rates with MFX. Reoperation rates were noted to be similar between the 3 procedures (25% for ACI, 21% for MFX, and 28% for OATS) at an average 3.7 years following the index procedure. When considering these 2 systematic reviews together, despite a faster RTS rate following MFX, a greater proportion of patients seem to be able to RTS over time following other procedures such as OATS, OCA, and ACI. Unfortunately, these reviews do not provide insight as to the role, if any, of reoperation on return to play rates nor on overall clinical outcome scores on patients undergoing articular cartilage surgery. However, this information is valuable when counseling athletes who are in season and would like to RTS as soon as possible as opposed to those who do not have tight time constraints for when they need to RTS.

Regardless of the cartilage technique chosen, the goals of surgery remain similar—to reduce pain and improve function. For athletes, the ultimate goal is to return to the same level of play that the athlete was able to achieve prior to injury. Certainly, the need for reoperation following a cartilage surgery has implications on pain, function, and ability to RTS. Our review of nearly 50,000 cartilage surgeries demonstrates that reoperations following cartilage repair surgery are not uncommon, with a rate of 14.90% at 2 years, and that while reoperation rates are the highest following ACI, the rate of conversion to knee arthroplasty is highest following MFX. Due to the limitations of the PearlDiver database, it is not possible to determine the clinical outcomes of patients undergoing reoperation following cartilage surgery, but certainly, given these data, reoperation is clearly not necessarily indicative of clinical failure. This is highlighted by the fact that the most common procedure performed at the time of reoperation is arthroscopic chondroplasty, which, despite being an additional surgical procedure, may be acceptable for patients who wish to RTS, particularly in the setting of an index ACI in which there may be graft hypertrophy. Ideally, additional studies incorporating a cost-effectiveness analysis of each of the procedures, incorporating reoperation rates as well as patient-reported clinical outcomes, would be helpful to truly determine the patient and societal implications of reoperation following cartilage repair/restoration.

Many of the advantages and disadvantages of the described cartilage repair/restoration procedures have been well described.^10-17 Microfracture is the most commonly utilized first-line repair/restoration option for small articular cartilage lesions, mainly due to its low cost, low morbidity, and relatively low level of difficulty.18 Despite these advantages, MFX is not without limitations, and the need for revision cartilage restoration and/or conversion to arthroplasty is concerning. In 2013, Salzmann and colleagues19 evaluated a cohort of 454 patients undergoing MFX for a symptomatic knee defect and noted a reoperation rate of 26.9% (n = 123) within 2 years of the index surgery, with risk factors for reoperation noted to include an increased number of pre-MFX ipsilateral knee surgeries, patellofemoral lesions, smoking, and lower preoperative numeric analog scale scores. The definition of reoperation in their study is unfortunately not described, and thus the extent of reoperation (arthroscopy to arthroplasty) is unclear. In a 2009 systematic review of 3122 patients (28 studies) undergoing MFX conducted by Mithoefer and colleagues,²⁰ revision rates were noted to range from 2% to 31% depending on the study analyzed, with increasing revision rates after 2 years. Unfortunately, the heterogeneity of the included studies makes it difficult to determine which patients tend to fail over time.

Continue to: OATS...

OATS is a promising cartilage restoration technique indicated for treatment of patients with large, uncontained chondral lesions, and/or lesions with both bone and cartilage loss.¹ OCA is similar to OATS but uses allograft tissue instead of autograft tissue and is typically considered a viable treatment option in larger lesions (>2 cm²).²¹ Cell-based ACI therapy has evolved substantially over the past decade and is now available as a third-generation model utilizing biodegradable 3-dimensional scaffolds seeded with chondrocytes. Reoperation rates following ACI can often be higher than those following other cartilage treatments, particularly given the known complication of graft hypertrophy and/or delamination. Harris and colleagues²² conducted a systematic review of 5276 subjects undergoing ACI (all generations), noting an overall reoperation rate of 33%, but a failure rate of 5.8% at an average of 22 months following ACI. Risk factors for reoperation included periosteal-based ACI as well as open (vs arthroscopic) ACI. In this study, we found a modestly lower return to OR rate of 29.69% at 2 years.

When the outcomes of patients undergoing OATS or OCA are compared to those of patients undergoing MFX or ACI, it can be difficult to interpret the results, as the indications for performing these procedures tend to be very different. Further, the reasons for reoperation, as well as the procedures performed at the time of reoperation, are often poorly described, making it difficult to truly quantify the risk of reoperation and the implications of reoperation for patients undergoing any of these index cartilage procedures.

Overall, in this database, the return to the OR rate approaches 15% at 2 years following cartilage surgery, with cell-based therapy demonstrating higher reoperation rates at 2 years, without the risk of conversion to arthroplasty. Reoperation rates appear to stabilize at 1 year following surgery and consist mostly of minor arthroscopic procedures. These findings can help surgeons counsel patients as to the rate and type of reoperations that can be expected following cartilage surgery. Additional research incorporating patient-reported outcomes and patient-specific risk factors are needed to complement these data as to the impact of reoperations on overall clinical outcomes. Further, studies incorporating 90-day, 1-year, and 2-year costs associated with cartilage surgery will help to determine which index procedure is the most cost effective over the short- and long-term.

LIMITATIONS

This study is not without limitations. The PearlDiver database is reliant upon accurate CPT and ICD-9 coding, which creates a potential for a reporting bias. The overall reliability of the analyses is dependent on the quality of the available data, which, as noted in previous PearlDiver studies,^18,23-28 may include inaccurate billing codes, miscoding, and/or non-coding by physicians as potential sources of error. At the time of this study, the PearlDiver database did not provide consistent data points on laterality, and thus it is possible that the reported rates of reoperation overestimate the true reoperation rate following a given procedure. Fortunately, the reoperation rates for each procedure analyzed in this database study are consistent with those previously presented in the literature. In addition, it is not uncommon for patients receiving one of these procedures to have previously been treated with one of the others. Due to the inherent limitations of the PearlDiver database, this study did not investigate concomitant procedures performed along with the index procedure, nor did it investigate confounding factors such as comorbidities. The PearlDiver database does not provide data on defect size, location within the knee, concomitant pathologies (eg, meniscus tear), prior surgeries, or patient comorbidities, and while important, these factors cannot be accounted for in our analysis. The inability to account for these important factors, particularly concomitant diagnoses, procedures, and lesion size/location, represents an important limitation of this study, as this is a source of selection bias and may influence the need for reoperation in a given patient. Despite these limitations, the results of this study are supported by previous and current literature. In addition, the PearlDiver database, as a HIPAA-compliant database, does not report exact numbers when the value of the outcome of interest is between 0 and 10, which prohibits analysis of any cartilage procedure performed in a cohort of patients greater than 1 and less than 11. Finally, while not necessarily a limitation, it should be noted that CPT 29879 is not specific for microfracture, as the code also includes abrasion arthroplasty and drilling. Due to the limitations of the methodology of searching the database for this code, it is unclear as to how many patients underwent actual microfracture vs abrasion arthroplasty.

CONCLUSION

Within a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference between failure/revision rates among the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

ABSTRACT

The purpose of this study is to describe the rate of return to the operating room (OR) following microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and osteochondral allograft (OCA) procedures at 90 days, 1 year, and 2 years. Current Procedural Terminology codes for all patients undergoing MFX, ACI, OATS, and OCA were used to search a prospectively collected, commercially available private payer insurance company database from 2007 to 2011. Within 90 days, 1 year, and 2 years after surgery, the database was searched for the occurrence of these same patients undergoing knee diagnostic arthroscopy with biopsy, lysis of adhesions, synovectomy, arthroscopy for infection or lavage, arthroscopy for removal of loose bodies, chondroplasty, MFX, ACI, OATS, OCA, and/or knee arthroplasty. Descriptive statistical analysis and contingency table analysis were performed. A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX, 640 ACI, 386 open OATS, 997 arthroscopic OATS, 714 open OCA, and 894 arthroscopic OCA procedures. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. At 2 years, patients who underwent MFX, ACI, OATS, OCA had reoperation rates of 14.65%, 29.69%, 8.82%, and 12.22%, respectively. There was a statistically significantly increased risk for ACI return to OR within all intervals (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative treatment options. With a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

Continue to: Symptomatic, full-thickness articular cartilage

Symptomatic, full-thickness articular cartilage defects in the knee are difficult to manage, particularly in the young, athletic patient population. Fortunately, a variety of cartilage repair (direct repair of the cartilage or those procedures which attempt to generate fibrocartilage) and restoration (those aimed at restoring hyaline cartilage) procedures are available, with encouraging short- and long-term clinical outcomes. After failure of nonoperative management, several surgical options are available for treating symptomatic focal chondral defects, including microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and open and arthroscopic osteochondral allograft (OCA) transplantation procedures.^1,2 When appropriately indicated, each of these techniques has demonstrated good to excellent clinical outcomes with respect to reducing pain and improving function.^3-5

While major complications following cartilage surgery are uncommon, the need for reoperation following an index articular cartilage operation is poorly understood. Recently, McCormick and colleagues6 found that reoperation within the first 2 years following meniscus allograft transplantation (MAT) is associated with an increased likelihood of revision MAT or future arthroplasty. Given the association between early reoperation following meniscus restoration surgery and subsequent failure, an improved understanding of the epidemiology and implications of reoperations following cartilage restoration surgery is warranted. Further, in deciding which treatment option is best suited to a particular patient, the rate of return to the operating room (OR) should be taken into consideration, as this could potentially influence surgical decision-making as to which procedure to perform, especially in value-based care decision-making environments.

The purpose of this study is to describe the rate of return to the OR for knee procedures following cartilage restoration at intervals of 90 days, 1 year, and 2 years across a large-scale US patient database. The authors hypothesize that the rate of return to the OR following knee cartilage repair or restoration procedures will be under 20% during the first post-operative year, with increasing reoperation rates over time. A secondary hypothesis is that there will be no difference in reoperation rates according to sex, but that younger patients (those younger than 40 years) will have higher reoperation rates than older patients.

METHODS

We performed a retrospective analysis of a prospectively collected, large-scale, and commercially available private payer insurance company database (PearlDiver) from 2007 to 2011. The PearlDiver database is a Health Insurance Portability and Accountability Act (HIPAA) compliant, publicly available national database consisting of a collection of private payer records, with United Health Group representing the contributing health plan. The database has more than 30 million patient records and contains Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) codes related to orthopedic procedures. From 2007 to 2011, the private payer database captured between 5.9 million and 6.2 million patients per year.

Our search was based on the CPT codes for MFX (29879), ACI (27412), OATS (29866, 29867), and OCA (27415, 27416). Return to the OR for revision surgery for the above-mentioned procedures was classified as patients with a diagnosis of diagnostic arthroscopy with biopsy (CPT 29870), lysis of adhesions (CPT 29884), synovectomy (29875, 29876), arthroscopy for infection or lavage (CPT 29871), arthroscopy for removal of loose bodies (29874), chondroplasty (29877), unicompartmental knee arthroplasty (27446), total knee arthroplasty (27447), and/or patellar arthroplasty (27438). Patient records were followed for reoperations occurring within 90 days, 1 year, and 2 years after the index cartilage procedure. All data were compared based on patient age and sex.

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analysis of this study was primarily descriptive to demonstrate the incidence for each code at each time interval. One-way analysis of variance, Chi-square analysis, and contingency tables were used to compare the incidence of each type of procedure throughout the various time intervals. A P-value of < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS v.20 (International Business Machines).

RESULTS

A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX (92.3%) 640 ACI (1.4%), 386 open OATS (0.82%), 997 arthroscopic OATS (2.11%), 714 open OCA (1.51%), and 894 arthroscopic OCA (1.89%) procedures. A summary of the procedures performed, broken down by age and sex, is provided in Tables 1 and 2. A total of 25,149 male patients (53.3%) underwent surgical procedures compared to 22,058 female patients (46.7%). For each category of procedure (MFX, ACI, OATS, OCA), there was a significantly higher proportion of males than females undergoing surgery (P < .0001 for all). Surgical treatment with MFX was consistently the most frequently performed surgery across all age groups (92.31%), while cell-based therapy with ACI was the least frequently performed procedure across all age ranges (1.36%). Restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not utilized in patients over 64 years of age (Table 2).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

A summary of all reoperation data is provided in Tables 3 to 7 and Figures 1 and 2. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. Patients who underwent MFX had reoperation rates of 6.05% at 90 days, 11.80% at 1 year, and 14.65% at 2 years. Patients who underwent ACI had reoperation rates of 4.53% at 90 days, 23.28% at 1 year, and 29.69% at 2 years. Patients who had open and arthroscopic OATS had reoperation rates of 3.122% and 5.12% at 90 days, 6.74% and 8.53% at 1 year, and 7.51% and 10.13% at 2 years, respectively. Patients who underwent open and arthroscopic OCA had reoperation rates of 2.52% and 3.91% at 90 days, 7.14% and 6.60% at 1 year, and 13.59% and 10.85% at 2 years (Table 3). There was a statistically significantly increased risk for reoperation following ACI within all intervals compared to all other surgical techniques (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty at 6.70%. There was no significant difference between failure rates (revision OATS/OCA or conversion to arthroplasty) between the restorative treatment options, with 14 failures for OATS (9.52% of reoperations at 2 years) compared to 22 failures for OCA (12.7% of reoperations at 2 years, P = .358). Among the entire cohort of cartilage surgery patients, arthroscopic chondroplasty was the most frequent procedure performed at the time of reoperation at all time points assessed, notably accounting for 33.08% of reoperations 2 years following microfracture, 51.58% of reoperations at 2 years following ACI, 53.06% of reoperations at 2 years following OATS, and 54.07% of reoperations at 2 years following OCA (Figure 3, Tables 4–7).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; MFX, microfracture; OR, operating room.

^aA -1 denotes No. <11 within the PearlDiver database, and exact numbers are not reported due to patient privacy considerations.

Abbreviations: ACI, autologous chondrocyte implantation; CPT, Current Procedural Terminology; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OCA, osteochondral allograft; OR, operating room.

Continue to: Discussion...

DISCUSSION

The principle findings of this study demonstrate that there is an overall reoperation rate of 14.90% at 2 years following cartilage repair/restoration surgery, with the highest reoperation rates following MFX at 90 days, and ACI at both 1 year and 2 years following the index procedure. Also, patients undergoing index MFX as the index procedure have the highest risk for conversion to arthroplasty, reoperation rates for all cartilage surgeries increase over time, and arthroscopic chondroplasty is the most frequent procedure performed at the time of reoperation.

The management of symptomatic articular cartilage knee pathology is extremely challenging. With improvements in surgical technique, instrumentation, and clinical decision-making, indications are constantly evolving. Techniques that may work for “small” defects, though there is some debate as to what constitutes a “small” defect, are not necessarily going to be successful for larger defects, and this certainly varies depending on where the defect is located within the knee joint (distal femur vs patella vs trochlea, etc.). Recently, in a 2015 analysis of 3 level I or II studies, Miller and colleagues⁷ demonstrated both MFX and OATS to be viable, cost-effective, first-line treatment options for articular cartilage injuries, with similar clinical outcomes at 8.7 years. The authors noted cumulative reoperation rates of 29% among patients undergoing MFX compared to 13% among patients undergoing OATS. While ACI and OCA procedures were not included in their study, the reported reoperation rates of 29% following MFX and 13% following OATS at nearly 10 years suggest a possible increased need for reoperation following MFX over time (approximately 15% at 2 years in our study) and a stable rate of reoperation following OATS (approximately 11% at 2 years in our study). This finding is significant, as one of the goals with these procedures is to deliver effective, long-lasting pain relief and restoration of function. Interestingly, in this study, restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not performed in patients older than 64 years. This may be explained by the higher prevalence of acute traumatic injuries and osteochondritis dissecans diagnoses in younger patients compared with older patients, as these diagnoses are more often indicated to undergo restorative procedures as opposed to marrow stimulation.

In a 2016 systematic review of 20 studies incorporating 1117 patients, Campbell and colleagues⁸ assessed return-to-play rates following MFX, ACI, OATS, and OCA. The authors noted that return to sport (RTS) rates were greatest following OATS (89%), followed by OCA (88%), ACI (84%), and MFX (75%). Positive prognostic factors for RTS included younger age, shorter duration of preoperative symptoms, no history of prior ipsilateral knee surgery, and smaller chondral defects. Reoperation rates between the 4 techniques were not statistically compared in their study. Interestingly, in 2013, Chalmers and colleagues⁹ conducted a separate systematic review of 20 studies comprising 1375 patients undergoing MFX, ACI, or OATS. In their study, the authors found significant advantages following ACI and OATS compared to MFX with respect to patient-reported outcome scores but noted significantly faster RTS rates with MFX. Reoperation rates were noted to be similar between the 3 procedures (25% for ACI, 21% for MFX, and 28% for OATS) at an average 3.7 years following the index procedure. When considering these 2 systematic reviews together, despite a faster RTS rate following MFX, a greater proportion of patients seem to be able to RTS over time following other procedures such as OATS, OCA, and ACI. Unfortunately, these reviews do not provide insight as to the role, if any, of reoperation on return to play rates nor on overall clinical outcome scores on patients undergoing articular cartilage surgery. However, this information is valuable when counseling athletes who are in season and would like to RTS as soon as possible as opposed to those who do not have tight time constraints for when they need to RTS.

Regardless of the cartilage technique chosen, the goals of surgery remain similar—to reduce pain and improve function. For athletes, the ultimate goal is to return to the same level of play that the athlete was able to achieve prior to injury. Certainly, the need for reoperation following a cartilage surgery has implications on pain, function, and ability to RTS. Our review of nearly 50,000 cartilage surgeries demonstrates that reoperations following cartilage repair surgery are not uncommon, with a rate of 14.90% at 2 years, and that while reoperation rates are the highest following ACI, the rate of conversion to knee arthroplasty is highest following MFX. Due to the limitations of the PearlDiver database, it is not possible to determine the clinical outcomes of patients undergoing reoperation following cartilage surgery, but certainly, given these data, reoperation is clearly not necessarily indicative of clinical failure. This is highlighted by the fact that the most common procedure performed at the time of reoperation is arthroscopic chondroplasty, which, despite being an additional surgical procedure, may be acceptable for patients who wish to RTS, particularly in the setting of an index ACI in which there may be graft hypertrophy. Ideally, additional studies incorporating a cost-effectiveness analysis of each of the procedures, incorporating reoperation rates as well as patient-reported clinical outcomes, would be helpful to truly determine the patient and societal implications of reoperation following cartilage repair/restoration.

Many of the advantages and disadvantages of the described cartilage repair/restoration procedures have been well described.^10-17 Microfracture is the most commonly utilized first-line repair/restoration option for small articular cartilage lesions, mainly due to its low cost, low morbidity, and relatively low level of difficulty.18 Despite these advantages, MFX is not without limitations, and the need for revision cartilage restoration and/or conversion to arthroplasty is concerning. In 2013, Salzmann and colleagues19 evaluated a cohort of 454 patients undergoing MFX for a symptomatic knee defect and noted a reoperation rate of 26.9% (n = 123) within 2 years of the index surgery, with risk factors for reoperation noted to include an increased number of pre-MFX ipsilateral knee surgeries, patellofemoral lesions, smoking, and lower preoperative numeric analog scale scores. The definition of reoperation in their study is unfortunately not described, and thus the extent of reoperation (arthroscopy to arthroplasty) is unclear. In a 2009 systematic review of 3122 patients (28 studies) undergoing MFX conducted by Mithoefer and colleagues,²⁰ revision rates were noted to range from 2% to 31% depending on the study analyzed, with increasing revision rates after 2 years. Unfortunately, the heterogeneity of the included studies makes it difficult to determine which patients tend to fail over time.

Continue to: OATS...

OATS is a promising cartilage restoration technique indicated for treatment of patients with large, uncontained chondral lesions, and/or lesions with both bone and cartilage loss.¹ OCA is similar to OATS but uses allograft tissue instead of autograft tissue and is typically considered a viable treatment option in larger lesions (>2 cm²).²¹ Cell-based ACI therapy has evolved substantially over the past decade and is now available as a third-generation model utilizing biodegradable 3-dimensional scaffolds seeded with chondrocytes. Reoperation rates following ACI can often be higher than those following other cartilage treatments, particularly given the known complication of graft hypertrophy and/or delamination. Harris and colleagues²² conducted a systematic review of 5276 subjects undergoing ACI (all generations), noting an overall reoperation rate of 33%, but a failure rate of 5.8% at an average of 22 months following ACI. Risk factors for reoperation included periosteal-based ACI as well as open (vs arthroscopic) ACI. In this study, we found a modestly lower return to OR rate of 29.69% at 2 years.

When the outcomes of patients undergoing OATS or OCA are compared to those of patients undergoing MFX or ACI, it can be difficult to interpret the results, as the indications for performing these procedures tend to be very different. Further, the reasons for reoperation, as well as the procedures performed at the time of reoperation, are often poorly described, making it difficult to truly quantify the risk of reoperation and the implications of reoperation for patients undergoing any of these index cartilage procedures.

Overall, in this database, the return to the OR rate approaches 15% at 2 years following cartilage surgery, with cell-based therapy demonstrating higher reoperation rates at 2 years, without the risk of conversion to arthroplasty. Reoperation rates appear to stabilize at 1 year following surgery and consist mostly of minor arthroscopic procedures. These findings can help surgeons counsel patients as to the rate and type of reoperations that can be expected following cartilage surgery. Additional research incorporating patient-reported outcomes and patient-specific risk factors are needed to complement these data as to the impact of reoperations on overall clinical outcomes. Further, studies incorporating 90-day, 1-year, and 2-year costs associated with cartilage surgery will help to determine which index procedure is the most cost effective over the short- and long-term.

LIMITATIONS

This study is not without limitations. The PearlDiver database is reliant upon accurate CPT and ICD-9 coding, which creates a potential for a reporting bias. The overall reliability of the analyses is dependent on the quality of the available data, which, as noted in previous PearlDiver studies,^18,23-28 may include inaccurate billing codes, miscoding, and/or non-coding by physicians as potential sources of error. At the time of this study, the PearlDiver database did not provide consistent data points on laterality, and thus it is possible that the reported rates of reoperation overestimate the true reoperation rate following a given procedure. Fortunately, the reoperation rates for each procedure analyzed in this database study are consistent with those previously presented in the literature. In addition, it is not uncommon for patients receiving one of these procedures to have previously been treated with one of the others. Due to the inherent limitations of the PearlDiver database, this study did not investigate concomitant procedures performed along with the index procedure, nor did it investigate confounding factors such as comorbidities. The PearlDiver database does not provide data on defect size, location within the knee, concomitant pathologies (eg, meniscus tear), prior surgeries, or patient comorbidities, and while important, these factors cannot be accounted for in our analysis. The inability to account for these important factors, particularly concomitant diagnoses, procedures, and lesion size/location, represents an important limitation of this study, as this is a source of selection bias and may influence the need for reoperation in a given patient. Despite these limitations, the results of this study are supported by previous and current literature. In addition, the PearlDiver database, as a HIPAA-compliant database, does not report exact numbers when the value of the outcome of interest is between 0 and 10, which prohibits analysis of any cartilage procedure performed in a cohort of patients greater than 1 and less than 11. Finally, while not necessarily a limitation, it should be noted that CPT 29879 is not specific for microfracture, as the code also includes abrasion arthroplasty and drilling. Due to the limitations of the methodology of searching the database for this code, it is unclear as to how many patients underwent actual microfracture vs abrasion arthroplasty.

CONCLUSION

Within a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference between failure/revision rates among the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

ABSTRACT

Instability of the proximal tibiofibular joint (PTFJ) is a rare clinical condition that presents unique challenges to treatment. We present the case of an active 26-year-old woman with a 4-year history of recurrent PTFJ subluxations, treated surgically at our institution using a split biceps femoris tendon graft for PTFJ reconstruction. She underwent several attempts at nonoperative management until we decided to proceed with surgical intervention. A split biceps femoris graft was used to restore stability of the PTFJ. Approximately 5 years postoperatively, she achieved full range of motion as well as functional and clinical Knee Society Scores of 94 and 90 points, respectively. To the best of our knowledge, this is the first case report of PTFJ instability treated surgically with long-term follow-up. Future studies should focus on the long-term satisfactory outcomes of soft tissue stabilization of a chronically unstable PTFJ.

The instability of the proximal tibiofibular joint (PTFJ) is a rare clinical condition that commonly occurs secondary to an initial pivoting or twisting event of a flexed knee. Although acute PTFJ dislocations respond well to closed reduction and casting, the treatment of chronic PTFJ instability presents a unique challenge.¹ Surgical fixation methods include tibiofibular joint recreation using either a split semitendinosus or biceps femoris graft, as well as a Tightrope device.^2-6 Older surgical options for chronic PTFJ instability include fibular head resection or PTFJ arthrodesis.⁷ However, these older techniques have fallen out of favor, and the optimal surgical technique for the treatment of this injury remains a point of contention.

We present the case of an active 26-year-old woman with a 4-year history of recurrent PTFJ subluxations. The patient was surgically treated at our institution by using a split biceps femoris tendon graft for PTFJ reconstruction. This article specifically details the surgical technique used, provides data obtained at the 5-year clinical follow-up, and reviews prior publications on this injury. The patient provided written informed consent for print and electronic publication of this case report.

CASE

A 26-year-old woman presented with a 4-year history of lateral right knee pain with any physical activity. She stated that her pain began immediately following a fall, which was initially treated with casting and immobilization for approximately 6 weeks. After treatment, she began to develop symptoms of “popping on the outside of the knee.” In the 8 months prior to her presentation to our practice, these symptoms had intensified in pain severity and frequency. She reported that the popping events occurred most often with deep squatting.

No gross deformity was observed upon physical examination, and both knees were visibly symmetric. Evidence of effusion was absent. The patient felt no pain with the passive motion of her knee, and she presented the full range of motion (ROM) from 0° to 120°. Anterior drawer, McMurray, Lachman, and pivot shift tests were all negative. Upon the application of manual pressure, the fibular head could be dislocated anteriorly (Video 1). This dislocation recreated the patient’s symptoms. The fibular head could not be subluxed or dislocated posteriorly. Flexing the knee to 90° facilitated reproducing manual anterior dislocation. The contralateral knee was examined and demonstrated no appreciable PTFJ instability. The patient exhibited no other signs of generalized ligamentous laxity. Her sensation in the lower leg was intact, and she reported no tingling or numbness in the peroneal nerve distribution. Tinel’s test of the peroneal nerve was negative.

Continue to: X-ray imaging revealed...

When the patient presented to our office, she reported having undergone several failed efforts of nonoperative treatment, including bracing and activity modification. On the basis of the chronicity of the reported symptoms, level of pain, and the desire of the patient to return to full activity, we recommended the surgical reconstruction of the PTFJ by using a split biceps femoris tendon graft.

OPERATIVE TECHNIQUE

The patient was positioned supine on a Jackson table. General anesthesia was utilized. Biplanar fluoroscopic imaging of the fibula was obtained with the fibular head manually dislocated and reduced. A bump was placed beneath the right thigh to create resting knee flexion. The patient was prepped and draped in sterile fashion, and a tourniquet was applied.

A 10-cm curvilinear surgical incision was made centered over the fibular neck and extending proximally within the interval between the iliotibial band and the biceps femoris tendon. Dissection was performed. The peroneal nerve was identified, carefully dissected out, and then isolated with a vessel loop. The biceps femoris tendon insertion on the fibular head was dissected while ensuring that the nerve was isolated, and the anterior half of the tendon was marked approximately 14 cm proximally using a surgical marker. A 15-blade was then used to split the tendon proximally along the marked path while taking care to preserve the tendinous insertion on the fibular head. The split portion of the tendon was freed from all underlying tissue, and the most distal 2 cm was tubularized using a running baseball stitch and No. 2 Ethibond.

The anterior and posterior aspects of the fibular head were then débrided of tissue, and a guidewire was placed anteriorly-to-posterior. After the position of the guidewire was confirmed with fluoroscopy, a 5-0 cannulated reamer was used to drill through the fibular head. Next, the interval between the biceps femoris and iliotibial band was found, and the lateral head of the gastrocnemius was retracted posteriorly within this interval. A portion of the soleus muscle was also elevated off of the posterior capsule and posterior tibia. The iliotibial band insertion at Gerdy’s tubercle was then identified, and a guidewire was placed from anterior-to-posterior within the tibia, with the starting point just posterior to Gerdy’s tubercle. The wire was advanced under direct visualization with an ACL tibial guide and confirmed fluoroscopically. A 5-mm cannulated reamer was then used to drill over the guidewire through the anterior and posterior cortex of the tibia. A suture passer was passed anterior-to-posterior through this tunnel to retrieve the tubularized portion of the biceps femoris graft, which was then shuttled through the tibial tunnel. This same tubularized graft segment was then shuttled anteriorly-to-posteriorly through the fibular tunnel. At this point, approximately 3 cm of the graft protruded from the posterior aspect of the fibular tunnel.

Continue to: The remaining graft was held...

POSTOPERATIVE COURSE

The patient was initially kept in a knee immobilizer following surgery and instructed to use touch-down weight-bearing for 3 weeks. She was switched to a hinged brace at 1 week postoperatively. Physical therapy began with range of motion exercises, and an active flexion was withheld until 6 weeks postoperatively. After 6 weeks, the patient was allowed to progress to an active ROM and increase to weight-bearing as tolerated.  Strengthening was started at 12 weeks.

MRI was performed at 4 months postoperatively because the patient reported pain with running. The MRI demonstrated no evidence of stress reaction or fracture in the area of reconstruction. She was advised to continue with physical therapy and stop running. At 5-month post-reconstruction, the patient reported that her pain had resolved and that she had no complaints of any peroneal nerve neuropraxia. At 6 months she had returned to normal activity without complaints. At this point, she was instructed to follow-up as needed.

The patient was seen in office 5.5 years after the initial surgery for an unrelated orthopedic issue. At this time, follow-up data were obtained for her PTFJ reconstruction. She stated that she was very satisfied with the results of her surgery. She claimed to be pain free and had been performing normal activities without any difficulty. Upon physical examination, she achieved full range of motion.  She had no extension lag or flexion contracture. She achieved functional and clinical Knee Society Scores of 94 and 90 points, respectively.

DISCUSSION

This article details a soft tissue PTFJ reconstruction using a split biceps femoris graft with over 5 years of clinical follow-up. Chronic PTFJ instability is a rare clinical entity, and unless gross instability is evident upon physical examination, its diagnosis may be confused with the diagnosis of more common complaints, such as meniscal tears or iliotibial band syndrome.

Continue to: Ogden first described...

Past instances of PTFJ instability have been managed with closed reduction and protected weight-bearing, as well as with various open reduction techniques.^2-7 Surgical reconstruction is commonly considered in chronic cases or if nonoperative modalities have failed. Although PTFJ arthrodesis or fibular head resection has been used as a prior treatment option, the postoperative complications associated with each of these techniques have since caused them to fall out of favor.

The split biceps femoris graft has been successfully used in the soft tissue reconstruction of PTFJ.^3,5-7 The soft tissue reconstruction of the PTFJ provides advantages over arthrodesis or fibular head resection because it preserves normal anatomy and avoids secondary stresses to the ankle encountered in the latter procedure. Fibular head resection also presents secondary complications, such as the loss of the biceps femoris and posterolateral corner ligament insertion points.⁹ Similar to this study, prior works have reported returns to functionality. However, this study represents the longest clinical postoperative follow-up of PTFJ ligament reconstruction. By using a split biceps graft, the insertion point of the biceps on the fibular head is preserved, thus maintaining normal function while still allowing for an easily tubularized graft for anatomic PTFJ ligament reconstruction.

CONSLUSION

We present data for over 5 years of follow-up for our surgical approach to this rare pathology. To the best of our knowledge, this is the first case report of PTFJ instability that was treated surgically and with a long-term follow-up. The patient did not demonstrate loss of knee motion, pain, or peroneal nerve symptoms. Moreover, she was very satisfied with the procedure at the most recent follow-up and had returned to unrestricted activity. The soft tissue stabilization of a chronically unstable PTFJ is a viable treatment modality that provides good results, and future studies should confirm these satisfactory outcomes in the long-term.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Instability of the proximal tibiofibular joint (PTFJ) is a rare clinical condition that presents unique challenges to treatment. We present the case of an active 26-year-old woman with a 4-year history of recurrent PTFJ subluxations, treated surgically at our institution using a split biceps femoris tendon graft for PTFJ reconstruction. She underwent several attempts at nonoperative management until we decided to proceed with surgical intervention. A split biceps femoris graft was used to restore stability of the PTFJ. Approximately 5 years postoperatively, she achieved full range of motion as well as functional and clinical Knee Society Scores of 94 and 90 points, respectively. To the best of our knowledge, this is the first case report of PTFJ instability treated surgically with long-term follow-up. Future studies should focus on the long-term satisfactory outcomes of soft tissue stabilization of a chronically unstable PTFJ.

The instability of the proximal tibiofibular joint (PTFJ) is a rare clinical condition that commonly occurs secondary to an initial pivoting or twisting event of a flexed knee. Although acute PTFJ dislocations respond well to closed reduction and casting, the treatment of chronic PTFJ instability presents a unique challenge.¹ Surgical fixation methods include tibiofibular joint recreation using either a split semitendinosus or biceps femoris graft, as well as a Tightrope device.^2-6 Older surgical options for chronic PTFJ instability include fibular head resection or PTFJ arthrodesis.⁷ However, these older techniques have fallen out of favor, and the optimal surgical technique for the treatment of this injury remains a point of contention.

We present the case of an active 26-year-old woman with a 4-year history of recurrent PTFJ subluxations. The patient was surgically treated at our institution by using a split biceps femoris tendon graft for PTFJ reconstruction. This article specifically details the surgical technique used, provides data obtained at the 5-year clinical follow-up, and reviews prior publications on this injury. The patient provided written informed consent for print and electronic publication of this case report.

CASE

A 26-year-old woman presented with a 4-year history of lateral right knee pain with any physical activity. She stated that her pain began immediately following a fall, which was initially treated with casting and immobilization for approximately 6 weeks. After treatment, she began to develop symptoms of “popping on the outside of the knee.” In the 8 months prior to her presentation to our practice, these symptoms had intensified in pain severity and frequency. She reported that the popping events occurred most often with deep squatting.

No gross deformity was observed upon physical examination, and both knees were visibly symmetric. Evidence of effusion was absent. The patient felt no pain with the passive motion of her knee, and she presented the full range of motion (ROM) from 0° to 120°. Anterior drawer, McMurray, Lachman, and pivot shift tests were all negative. Upon the application of manual pressure, the fibular head could be dislocated anteriorly (Video 1). This dislocation recreated the patient’s symptoms. The fibular head could not be subluxed or dislocated posteriorly. Flexing the knee to 90° facilitated reproducing manual anterior dislocation. The contralateral knee was examined and demonstrated no appreciable PTFJ instability. The patient exhibited no other signs of generalized ligamentous laxity. Her sensation in the lower leg was intact, and she reported no tingling or numbness in the peroneal nerve distribution. Tinel’s test of the peroneal nerve was negative.

Continue to: X-ray imaging revealed...

When the patient presented to our office, she reported having undergone several failed efforts of nonoperative treatment, including bracing and activity modification. On the basis of the chronicity of the reported symptoms, level of pain, and the desire of the patient to return to full activity, we recommended the surgical reconstruction of the PTFJ by using a split biceps femoris tendon graft.

OPERATIVE TECHNIQUE

The patient was positioned supine on a Jackson table. General anesthesia was utilized. Biplanar fluoroscopic imaging of the fibula was obtained with the fibular head manually dislocated and reduced. A bump was placed beneath the right thigh to create resting knee flexion. The patient was prepped and draped in sterile fashion, and a tourniquet was applied.

A 10-cm curvilinear surgical incision was made centered over the fibular neck and extending proximally within the interval between the iliotibial band and the biceps femoris tendon. Dissection was performed. The peroneal nerve was identified, carefully dissected out, and then isolated with a vessel loop. The biceps femoris tendon insertion on the fibular head was dissected while ensuring that the nerve was isolated, and the anterior half of the tendon was marked approximately 14 cm proximally using a surgical marker. A 15-blade was then used to split the tendon proximally along the marked path while taking care to preserve the tendinous insertion on the fibular head. The split portion of the tendon was freed from all underlying tissue, and the most distal 2 cm was tubularized using a running baseball stitch and No. 2 Ethibond.

The anterior and posterior aspects of the fibular head were then débrided of tissue, and a guidewire was placed anteriorly-to-posterior. After the position of the guidewire was confirmed with fluoroscopy, a 5-0 cannulated reamer was used to drill through the fibular head. Next, the interval between the biceps femoris and iliotibial band was found, and the lateral head of the gastrocnemius was retracted posteriorly within this interval. A portion of the soleus muscle was also elevated off of the posterior capsule and posterior tibia. The iliotibial band insertion at Gerdy’s tubercle was then identified, and a guidewire was placed from anterior-to-posterior within the tibia, with the starting point just posterior to Gerdy’s tubercle. The wire was advanced under direct visualization with an ACL tibial guide and confirmed fluoroscopically. A 5-mm cannulated reamer was then used to drill over the guidewire through the anterior and posterior cortex of the tibia. A suture passer was passed anterior-to-posterior through this tunnel to retrieve the tubularized portion of the biceps femoris graft, which was then shuttled through the tibial tunnel. This same tubularized graft segment was then shuttled anteriorly-to-posteriorly through the fibular tunnel. At this point, approximately 3 cm of the graft protruded from the posterior aspect of the fibular tunnel.

Continue to: The remaining graft was held...

POSTOPERATIVE COURSE

The patient was initially kept in a knee immobilizer following surgery and instructed to use touch-down weight-bearing for 3 weeks. She was switched to a hinged brace at 1 week postoperatively. Physical therapy began with range of motion exercises, and an active flexion was withheld until 6 weeks postoperatively. After 6 weeks, the patient was allowed to progress to an active ROM and increase to weight-bearing as tolerated.  Strengthening was started at 12 weeks.

MRI was performed at 4 months postoperatively because the patient reported pain with running. The MRI demonstrated no evidence of stress reaction or fracture in the area of reconstruction. She was advised to continue with physical therapy and stop running. At 5-month post-reconstruction, the patient reported that her pain had resolved and that she had no complaints of any peroneal nerve neuropraxia. At 6 months she had returned to normal activity without complaints. At this point, she was instructed to follow-up as needed.

The patient was seen in office 5.5 years after the initial surgery for an unrelated orthopedic issue. At this time, follow-up data were obtained for her PTFJ reconstruction. She stated that she was very satisfied with the results of her surgery. She claimed to be pain free and had been performing normal activities without any difficulty. Upon physical examination, she achieved full range of motion.  She had no extension lag or flexion contracture. She achieved functional and clinical Knee Society Scores of 94 and 90 points, respectively.

DISCUSSION

This article details a soft tissue PTFJ reconstruction using a split biceps femoris graft with over 5 years of clinical follow-up. Chronic PTFJ instability is a rare clinical entity, and unless gross instability is evident upon physical examination, its diagnosis may be confused with the diagnosis of more common complaints, such as meniscal tears or iliotibial band syndrome.

Continue to: Ogden first described...

Past instances of PTFJ instability have been managed with closed reduction and protected weight-bearing, as well as with various open reduction techniques.^2-7 Surgical reconstruction is commonly considered in chronic cases or if nonoperative modalities have failed. Although PTFJ arthrodesis or fibular head resection has been used as a prior treatment option, the postoperative complications associated with each of these techniques have since caused them to fall out of favor.

The split biceps femoris graft has been successfully used in the soft tissue reconstruction of PTFJ.^3,5-7 The soft tissue reconstruction of the PTFJ provides advantages over arthrodesis or fibular head resection because it preserves normal anatomy and avoids secondary stresses to the ankle encountered in the latter procedure. Fibular head resection also presents secondary complications, such as the loss of the biceps femoris and posterolateral corner ligament insertion points.⁹ Similar to this study, prior works have reported returns to functionality. However, this study represents the longest clinical postoperative follow-up of PTFJ ligament reconstruction. By using a split biceps graft, the insertion point of the biceps on the fibular head is preserved, thus maintaining normal function while still allowing for an easily tubularized graft for anatomic PTFJ ligament reconstruction.

CONSLUSION

We present data for over 5 years of follow-up for our surgical approach to this rare pathology. To the best of our knowledge, this is the first case report of PTFJ instability that was treated surgically and with a long-term follow-up. The patient did not demonstrate loss of knee motion, pain, or peroneal nerve symptoms. Moreover, she was very satisfied with the procedure at the most recent follow-up and had returned to unrestricted activity. The soft tissue stabilization of a chronically unstable PTFJ is a viable treatment modality that provides good results, and future studies should confirm these satisfactory outcomes in the long-term.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Instability of the proximal tibiofibular joint (PTFJ) is a rare clinical condition that presents unique challenges to treatment. We present the case of an active 26-year-old woman with a 4-year history of recurrent PTFJ subluxations, treated surgically at our institution using a split biceps femoris tendon graft for PTFJ reconstruction. She underwent several attempts at nonoperative management until we decided to proceed with surgical intervention. A split biceps femoris graft was used to restore stability of the PTFJ. Approximately 5 years postoperatively, she achieved full range of motion as well as functional and clinical Knee Society Scores of 94 and 90 points, respectively. To the best of our knowledge, this is the first case report of PTFJ instability treated surgically with long-term follow-up. Future studies should focus on the long-term satisfactory outcomes of soft tissue stabilization of a chronically unstable PTFJ.

The instability of the proximal tibiofibular joint (PTFJ) is a rare clinical condition that commonly occurs secondary to an initial pivoting or twisting event of a flexed knee. Although acute PTFJ dislocations respond well to closed reduction and casting, the treatment of chronic PTFJ instability presents a unique challenge.¹ Surgical fixation methods include tibiofibular joint recreation using either a split semitendinosus or biceps femoris graft, as well as a Tightrope device.^2-6 Older surgical options for chronic PTFJ instability include fibular head resection or PTFJ arthrodesis.⁷ However, these older techniques have fallen out of favor, and the optimal surgical technique for the treatment of this injury remains a point of contention.

We present the case of an active 26-year-old woman with a 4-year history of recurrent PTFJ subluxations. The patient was surgically treated at our institution by using a split biceps femoris tendon graft for PTFJ reconstruction. This article specifically details the surgical technique used, provides data obtained at the 5-year clinical follow-up, and reviews prior publications on this injury. The patient provided written informed consent for print and electronic publication of this case report.

CASE

A 26-year-old woman presented with a 4-year history of lateral right knee pain with any physical activity. She stated that her pain began immediately following a fall, which was initially treated with casting and immobilization for approximately 6 weeks. After treatment, she began to develop symptoms of “popping on the outside of the knee.” In the 8 months prior to her presentation to our practice, these symptoms had intensified in pain severity and frequency. She reported that the popping events occurred most often with deep squatting.

No gross deformity was observed upon physical examination, and both knees were visibly symmetric. Evidence of effusion was absent. The patient felt no pain with the passive motion of her knee, and she presented the full range of motion (ROM) from 0° to 120°. Anterior drawer, McMurray, Lachman, and pivot shift tests were all negative. Upon the application of manual pressure, the fibular head could be dislocated anteriorly (Video 1). This dislocation recreated the patient’s symptoms. The fibular head could not be subluxed or dislocated posteriorly. Flexing the knee to 90° facilitated reproducing manual anterior dislocation. The contralateral knee was examined and demonstrated no appreciable PTFJ instability. The patient exhibited no other signs of generalized ligamentous laxity. Her sensation in the lower leg was intact, and she reported no tingling or numbness in the peroneal nerve distribution. Tinel’s test of the peroneal nerve was negative.

Continue to: X-ray imaging revealed...

When the patient presented to our office, she reported having undergone several failed efforts of nonoperative treatment, including bracing and activity modification. On the basis of the chronicity of the reported symptoms, level of pain, and the desire of the patient to return to full activity, we recommended the surgical reconstruction of the PTFJ by using a split biceps femoris tendon graft.

OPERATIVE TECHNIQUE

The patient was positioned supine on a Jackson table. General anesthesia was utilized. Biplanar fluoroscopic imaging of the fibula was obtained with the fibular head manually dislocated and reduced. A bump was placed beneath the right thigh to create resting knee flexion. The patient was prepped and draped in sterile fashion, and a tourniquet was applied.

A 10-cm curvilinear surgical incision was made centered over the fibular neck and extending proximally within the interval between the iliotibial band and the biceps femoris tendon. Dissection was performed. The peroneal nerve was identified, carefully dissected out, and then isolated with a vessel loop. The biceps femoris tendon insertion on the fibular head was dissected while ensuring that the nerve was isolated, and the anterior half of the tendon was marked approximately 14 cm proximally using a surgical marker. A 15-blade was then used to split the tendon proximally along the marked path while taking care to preserve the tendinous insertion on the fibular head. The split portion of the tendon was freed from all underlying tissue, and the most distal 2 cm was tubularized using a running baseball stitch and No. 2 Ethibond.

The anterior and posterior aspects of the fibular head were then débrided of tissue, and a guidewire was placed anteriorly-to-posterior. After the position of the guidewire was confirmed with fluoroscopy, a 5-0 cannulated reamer was used to drill through the fibular head. Next, the interval between the biceps femoris and iliotibial band was found, and the lateral head of the gastrocnemius was retracted posteriorly within this interval. A portion of the soleus muscle was also elevated off of the posterior capsule and posterior tibia. The iliotibial band insertion at Gerdy’s tubercle was then identified, and a guidewire was placed from anterior-to-posterior within the tibia, with the starting point just posterior to Gerdy’s tubercle. The wire was advanced under direct visualization with an ACL tibial guide and confirmed fluoroscopically. A 5-mm cannulated reamer was then used to drill over the guidewire through the anterior and posterior cortex of the tibia. A suture passer was passed anterior-to-posterior through this tunnel to retrieve the tubularized portion of the biceps femoris graft, which was then shuttled through the tibial tunnel. This same tubularized graft segment was then shuttled anteriorly-to-posteriorly through the fibular tunnel. At this point, approximately 3 cm of the graft protruded from the posterior aspect of the fibular tunnel.

Continue to: The remaining graft was held...

POSTOPERATIVE COURSE

The patient was initially kept in a knee immobilizer following surgery and instructed to use touch-down weight-bearing for 3 weeks. She was switched to a hinged brace at 1 week postoperatively. Physical therapy began with range of motion exercises, and an active flexion was withheld until 6 weeks postoperatively. After 6 weeks, the patient was allowed to progress to an active ROM and increase to weight-bearing as tolerated.  Strengthening was started at 12 weeks.

MRI was performed at 4 months postoperatively because the patient reported pain with running. The MRI demonstrated no evidence of stress reaction or fracture in the area of reconstruction. She was advised to continue with physical therapy and stop running. At 5-month post-reconstruction, the patient reported that her pain had resolved and that she had no complaints of any peroneal nerve neuropraxia. At 6 months she had returned to normal activity without complaints. At this point, she was instructed to follow-up as needed.

The patient was seen in office 5.5 years after the initial surgery for an unrelated orthopedic issue. At this time, follow-up data were obtained for her PTFJ reconstruction. She stated that she was very satisfied with the results of her surgery. She claimed to be pain free and had been performing normal activities without any difficulty. Upon physical examination, she achieved full range of motion.  She had no extension lag or flexion contracture. She achieved functional and clinical Knee Society Scores of 94 and 90 points, respectively.

DISCUSSION

This article details a soft tissue PTFJ reconstruction using a split biceps femoris graft with over 5 years of clinical follow-up. Chronic PTFJ instability is a rare clinical entity, and unless gross instability is evident upon physical examination, its diagnosis may be confused with the diagnosis of more common complaints, such as meniscal tears or iliotibial band syndrome.

Continue to: Ogden first described...

Past instances of PTFJ instability have been managed with closed reduction and protected weight-bearing, as well as with various open reduction techniques.^2-7 Surgical reconstruction is commonly considered in chronic cases or if nonoperative modalities have failed. Although PTFJ arthrodesis or fibular head resection has been used as a prior treatment option, the postoperative complications associated with each of these techniques have since caused them to fall out of favor.

The split biceps femoris graft has been successfully used in the soft tissue reconstruction of PTFJ.^3,5-7 The soft tissue reconstruction of the PTFJ provides advantages over arthrodesis or fibular head resection because it preserves normal anatomy and avoids secondary stresses to the ankle encountered in the latter procedure. Fibular head resection also presents secondary complications, such as the loss of the biceps femoris and posterolateral corner ligament insertion points.⁹ Similar to this study, prior works have reported returns to functionality. However, this study represents the longest clinical postoperative follow-up of PTFJ ligament reconstruction. By using a split biceps graft, the insertion point of the biceps on the fibular head is preserved, thus maintaining normal function while still allowing for an easily tubularized graft for anatomic PTFJ ligament reconstruction.

CONSLUSION

We present data for over 5 years of follow-up for our surgical approach to this rare pathology. To the best of our knowledge, this is the first case report of PTFJ instability that was treated surgically and with a long-term follow-up. The patient did not demonstrate loss of knee motion, pain, or peroneal nerve symptoms. Moreover, she was very satisfied with the procedure at the most recent follow-up and had returned to unrestricted activity. The soft tissue stabilization of a chronically unstable PTFJ is a viable treatment modality that provides good results, and future studies should confirm these satisfactory outcomes in the long-term.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

A central distal femoral physeal bone bridge in a boy aged 5 years and 7 months was resected with a fluoroscopically guided core reamer placed through a lateral parapatellar approach. At 3-year follow-up, the boy’s leg-length discrepancy was 3.0 cm (3.9 cm preoperatively), and the physeal bone bridge did not recur. The patient had full function and no pain or other patellofemoral complaints. This technique provided direct access to the physeal bone bridge, and complete resection was performed without injury to the adjacent physeal cartilage in the medial and lateral columns of the distal femur, which is expected to grow normally in the absence of the bridge.

A physeal bone bridge is an osseous connection that forms across a physis. It may cause partial premature physeal arrest. Angular deformity and limb-length discrepancy are the main complications caused by physeal bone bridges.^1-4 The indications for the treatment of physeal bridges are well documented.^1-5 Trauma and infection are common causes of distal femoral physeal bone bridges. Arkader and colleagues⁶ showed that among different types of physeal bridges, the Salter-Harris type is significantly associated with complications, among which growth arrest is the most common and occurs in 27.4% of all patients.

The treatment of distal femoral physeal bone bridges is technically difficult and provides variable results. Poor results are reported in 13% to 40% of patients.^7-10 Procedure failure has been attributed to incomplete resection with the persistent tethering and dislodgement of the graft.¹¹ Methods with improved efficacy for the removal of central physeal bridges will help prevent reformation after treatment. We have used a novel technique that allows the direct resection of a central physeal bone bridge in the distal femur through the use of a fluoroscopically guided core reamer. This technique enables the complete removal of the bone bridge and the direct visual assessment of the remaining physis. The patient’s parents provided written informed consent for print and electronic publication of this case report.

CASE

A 3-year-old boy with a history of hemifacial microsomia presented for the evaluation of genu valgum and leg-length discrepancy. His intermalleolar distance at that time was 8 cm. A standing radiograph of his lower extremities demonstrated changes consistent with physiologic genu valgum. He had no history of knee trauma, infection, or pain.

At the age of 5 years and 7 months, the patient returned for a repeat evaluation and was noted to exhibit the progressive valgus deformity of the right leg and a leg-length discrepancy of 3.9 cm (Figure 1). 

Continue to: With the patient supine on the operating...

OPERATIVE TECHNIQUE

With the patient supine on the operating table and after the administration of general anesthesia, 3-dimensional (3-D) fluoroscopy was used to localize the bone bridge, which confirmed the fluoroscopic location that was previously visualized through preoperative 3-D imaging. The leg was elevated, and a tourniquet was applied and inflated. A lateral parapatellar approach was used to isolate the distal femoral physis anteriorly because the bone bridge was centered just lateral to the central portion of the distal femoral physis. A Kirschner wire was placed in the center of the bridge under anteroposterior and lateral fluoroscopic imaging (Figures 3A-3E). 

OUTCOME

The patient healed uneventfully, and early range-of-motion exercises were started 6 weeks postoperatively. At 6-month follow-up, his leg-length discrepancy was 2.7 cm, and the bone bridge did not recur. At 3-year follow-up, his leg-length discrepancy was 3.0 cm, and the bone bridge did not recur. Over the 3 years postoperatively, the patient exhibited 9.8 cm of growth on his operative side and 9.5 cm on his nonoperative side (Figure 5). 

DISCUSSION

Given the considerable growth potential of the distal femoral physis,^1,14-16 an injury to the distal femoral physis and the formation of a physeal bone bridge can have a profound effect on a young patient in terms of leg-length discrepancy and angular deformity. Fracture from trauma or infection is a common cause of physeal bone bridges.^6,17-19 The etiology of our patient’s distal femoral physeal bone bridge is idiopathic, which is considerably less common than other etiologies, and the incidence of idiopathic physeal bone bridge formation is not well established in the literature. Hresko and Kasser²¹ identified atraumatic physeal bone bridge formations in 7 patients. Among the 13 patients with physeal bone bridges described by Broughton and colleagues,²⁰ the cause of bridge formation is unknown in 1.

Physeal bone bridges that form centrally are particularly challenging because they are difficult to visualize through a peripheral approach. A number of methods for resecting central physeal bone bridges have been described. These methods have varying degrees of success. In 1981, Langenskiöld⁷ first described the creation of a metaphyseal mirror and the use of a dental mirror for visualization. This technique, however, yielded unfavorable results in 16% of patients. Williamson and Staheli⁹ reported poor results in 23% of patients. Loraas and Schmale⁴ described the use of an endoscope, termed an osteoscope, for visualization, citing advantages of superior illumination and potential for image magnification and capture. Marsh and Polzhofer⁸ also showed this technique to have low morbidity but poor results in 13% of patients, whereas Moreta and colleagues¹⁰ reported poor results in 2 out of 5 patients. The rate of poor results of these methods may be related to the technical difficulty of using dental mirrors and arthroscopes and can be improved by highly efficient direct methods with improved visualization, such as the method described in this article.

Continue to: Proper imaging is necessary for...

Proper imaging is necessary for the accurate quantification of bone bridges to determine resectability and to identify the best surgical approach to resection. MRI with software for the generation of 3-D physeal maps is a reproducible method with good interobserver reliability.^22,23 Intraoperative computer-assisted imaging also is beneficial for determining the extent and location of the resection to ensure complete bone bridge removal.²⁴

To our knowledge, a direct approach through parapatellar arthrotomy for the resection of a centrally located distal femoral physeal bone bridge has not been previously described. This novel technique provided direct access to the physeal bone bridge and was performed without injuring the adjacent physeal cartilage in the medial and lateral columns of the distal femur, which may grow normally in the absence of the bridge. Instead of using a lateral or medial approach with a metaphyseal window,⁴ we directly approached this central bar through a parapatellar approach and were able to completely resect it under direct visualization. This obviated the need for an arthroscope or dental mirror. To remove the entire physeal bone bridge, we needed to resect completely from the anterior cortex to the posterior cortex. Although this technique potentially increased the risk of iatrogenic fracture, we believed that this risk would not differ greatly from that of disrupting the medial or lateral metaphysis and would be more stable with either axial and torsion load. At 3-year follow-up, the patient exhibited restored normal growth in his operative limb relative to that in his nonoperative limb, had not developed angular deformity, and had maintained his previously developed limb-length discrepancy that could be corrected with the epiphysiodesis of his opposite limb at a later date.

The limitations to this technique include the fact that it may be most effective with small-to moderate-sized central physeal bone bridges, although resection has shown good results with up to 70% physeal involvement.⁸ In this patient, the bone bridge was moderately sized (30% of the physis), centrally located, and clearly visible on fluoroscopy. These characteristics increased the technical safety and ease of the procedure. The resection of large, peripheral bridges may destabilize the distal femur. The destabilization of the distal femur, in turn, can lead to fracture. Patellofemoral mechanics may also be affected during the treatment of distal femoral physeal bone bridges. This patient has not experienced any patellofemoral dysfunction or symptoms. Given the patient’s age and significant amount of remaining growth, he will need close monitoring until he reaches skeletal maturity.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

A central distal femoral physeal bone bridge in a boy aged 5 years and 7 months was resected with a fluoroscopically guided core reamer placed through a lateral parapatellar approach. At 3-year follow-up, the boy’s leg-length discrepancy was 3.0 cm (3.9 cm preoperatively), and the physeal bone bridge did not recur. The patient had full function and no pain or other patellofemoral complaints. This technique provided direct access to the physeal bone bridge, and complete resection was performed without injury to the adjacent physeal cartilage in the medial and lateral columns of the distal femur, which is expected to grow normally in the absence of the bridge.

A physeal bone bridge is an osseous connection that forms across a physis. It may cause partial premature physeal arrest. Angular deformity and limb-length discrepancy are the main complications caused by physeal bone bridges.^1-4 The indications for the treatment of physeal bridges are well documented.^1-5 Trauma and infection are common causes of distal femoral physeal bone bridges. Arkader and colleagues⁶ showed that among different types of physeal bridges, the Salter-Harris type is significantly associated with complications, among which growth arrest is the most common and occurs in 27.4% of all patients.

The treatment of distal femoral physeal bone bridges is technically difficult and provides variable results. Poor results are reported in 13% to 40% of patients.^7-10 Procedure failure has been attributed to incomplete resection with the persistent tethering and dislodgement of the graft.¹¹ Methods with improved efficacy for the removal of central physeal bridges will help prevent reformation after treatment. We have used a novel technique that allows the direct resection of a central physeal bone bridge in the distal femur through the use of a fluoroscopically guided core reamer. This technique enables the complete removal of the bone bridge and the direct visual assessment of the remaining physis. The patient’s parents provided written informed consent for print and electronic publication of this case report.

CASE

A 3-year-old boy with a history of hemifacial microsomia presented for the evaluation of genu valgum and leg-length discrepancy. His intermalleolar distance at that time was 8 cm. A standing radiograph of his lower extremities demonstrated changes consistent with physiologic genu valgum. He had no history of knee trauma, infection, or pain.

At the age of 5 years and 7 months, the patient returned for a repeat evaluation and was noted to exhibit the progressive valgus deformity of the right leg and a leg-length discrepancy of 3.9 cm (Figure 1). 

Continue to: With the patient supine on the operating...

OPERATIVE TECHNIQUE

With the patient supine on the operating table and after the administration of general anesthesia, 3-dimensional (3-D) fluoroscopy was used to localize the bone bridge, which confirmed the fluoroscopic location that was previously visualized through preoperative 3-D imaging. The leg was elevated, and a tourniquet was applied and inflated. A lateral parapatellar approach was used to isolate the distal femoral physis anteriorly because the bone bridge was centered just lateral to the central portion of the distal femoral physis. A Kirschner wire was placed in the center of the bridge under anteroposterior and lateral fluoroscopic imaging (Figures 3A-3E). 

OUTCOME

The patient healed uneventfully, and early range-of-motion exercises were started 6 weeks postoperatively. At 6-month follow-up, his leg-length discrepancy was 2.7 cm, and the bone bridge did not recur. At 3-year follow-up, his leg-length discrepancy was 3.0 cm, and the bone bridge did not recur. Over the 3 years postoperatively, the patient exhibited 9.8 cm of growth on his operative side and 9.5 cm on his nonoperative side (Figure 5). 

DISCUSSION

Given the considerable growth potential of the distal femoral physis,^1,14-16 an injury to the distal femoral physis and the formation of a physeal bone bridge can have a profound effect on a young patient in terms of leg-length discrepancy and angular deformity. Fracture from trauma or infection is a common cause of physeal bone bridges.^6,17-19 The etiology of our patient’s distal femoral physeal bone bridge is idiopathic, which is considerably less common than other etiologies, and the incidence of idiopathic physeal bone bridge formation is not well established in the literature. Hresko and Kasser²¹ identified atraumatic physeal bone bridge formations in 7 patients. Among the 13 patients with physeal bone bridges described by Broughton and colleagues,²⁰ the cause of bridge formation is unknown in 1.

Physeal bone bridges that form centrally are particularly challenging because they are difficult to visualize through a peripheral approach. A number of methods for resecting central physeal bone bridges have been described. These methods have varying degrees of success. In 1981, Langenskiöld⁷ first described the creation of a metaphyseal mirror and the use of a dental mirror for visualization. This technique, however, yielded unfavorable results in 16% of patients. Williamson and Staheli⁹ reported poor results in 23% of patients. Loraas and Schmale⁴ described the use of an endoscope, termed an osteoscope, for visualization, citing advantages of superior illumination and potential for image magnification and capture. Marsh and Polzhofer⁸ also showed this technique to have low morbidity but poor results in 13% of patients, whereas Moreta and colleagues¹⁰ reported poor results in 2 out of 5 patients. The rate of poor results of these methods may be related to the technical difficulty of using dental mirrors and arthroscopes and can be improved by highly efficient direct methods with improved visualization, such as the method described in this article.

Continue to: Proper imaging is necessary for...

Proper imaging is necessary for the accurate quantification of bone bridges to determine resectability and to identify the best surgical approach to resection. MRI with software for the generation of 3-D physeal maps is a reproducible method with good interobserver reliability.^22,23 Intraoperative computer-assisted imaging also is beneficial for determining the extent and location of the resection to ensure complete bone bridge removal.²⁴

To our knowledge, a direct approach through parapatellar arthrotomy for the resection of a centrally located distal femoral physeal bone bridge has not been previously described. This novel technique provided direct access to the physeal bone bridge and was performed without injuring the adjacent physeal cartilage in the medial and lateral columns of the distal femur, which may grow normally in the absence of the bridge. Instead of using a lateral or medial approach with a metaphyseal window,⁴ we directly approached this central bar through a parapatellar approach and were able to completely resect it under direct visualization. This obviated the need for an arthroscope or dental mirror. To remove the entire physeal bone bridge, we needed to resect completely from the anterior cortex to the posterior cortex. Although this technique potentially increased the risk of iatrogenic fracture, we believed that this risk would not differ greatly from that of disrupting the medial or lateral metaphysis and would be more stable with either axial and torsion load. At 3-year follow-up, the patient exhibited restored normal growth in his operative limb relative to that in his nonoperative limb, had not developed angular deformity, and had maintained his previously developed limb-length discrepancy that could be corrected with the epiphysiodesis of his opposite limb at a later date.

The limitations to this technique include the fact that it may be most effective with small-to moderate-sized central physeal bone bridges, although resection has shown good results with up to 70% physeal involvement.⁸ In this patient, the bone bridge was moderately sized (30% of the physis), centrally located, and clearly visible on fluoroscopy. These characteristics increased the technical safety and ease of the procedure. The resection of large, peripheral bridges may destabilize the distal femur. The destabilization of the distal femur, in turn, can lead to fracture. Patellofemoral mechanics may also be affected during the treatment of distal femoral physeal bone bridges. This patient has not experienced any patellofemoral dysfunction or symptoms. Given the patient’s age and significant amount of remaining growth, he will need close monitoring until he reaches skeletal maturity.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

A central distal femoral physeal bone bridge in a boy aged 5 years and 7 months was resected with a fluoroscopically guided core reamer placed through a lateral parapatellar approach. At 3-year follow-up, the boy’s leg-length discrepancy was 3.0 cm (3.9 cm preoperatively), and the physeal bone bridge did not recur. The patient had full function and no pain or other patellofemoral complaints. This technique provided direct access to the physeal bone bridge, and complete resection was performed without injury to the adjacent physeal cartilage in the medial and lateral columns of the distal femur, which is expected to grow normally in the absence of the bridge.

A physeal bone bridge is an osseous connection that forms across a physis. It may cause partial premature physeal arrest. Angular deformity and limb-length discrepancy are the main complications caused by physeal bone bridges.^1-4 The indications for the treatment of physeal bridges are well documented.^1-5 Trauma and infection are common causes of distal femoral physeal bone bridges. Arkader and colleagues⁶ showed that among different types of physeal bridges, the Salter-Harris type is significantly associated with complications, among which growth arrest is the most common and occurs in 27.4% of all patients.

The treatment of distal femoral physeal bone bridges is technically difficult and provides variable results. Poor results are reported in 13% to 40% of patients.^7-10 Procedure failure has been attributed to incomplete resection with the persistent tethering and dislodgement of the graft.¹¹ Methods with improved efficacy for the removal of central physeal bridges will help prevent reformation after treatment. We have used a novel technique that allows the direct resection of a central physeal bone bridge in the distal femur through the use of a fluoroscopically guided core reamer. This technique enables the complete removal of the bone bridge and the direct visual assessment of the remaining physis. The patient’s parents provided written informed consent for print and electronic publication of this case report.

CASE

A 3-year-old boy with a history of hemifacial microsomia presented for the evaluation of genu valgum and leg-length discrepancy. His intermalleolar distance at that time was 8 cm. A standing radiograph of his lower extremities demonstrated changes consistent with physiologic genu valgum. He had no history of knee trauma, infection, or pain.

At the age of 5 years and 7 months, the patient returned for a repeat evaluation and was noted to exhibit the progressive valgus deformity of the right leg and a leg-length discrepancy of 3.9 cm (Figure 1). 

Continue to: With the patient supine on the operating...

OPERATIVE TECHNIQUE

With the patient supine on the operating table and after the administration of general anesthesia, 3-dimensional (3-D) fluoroscopy was used to localize the bone bridge, which confirmed the fluoroscopic location that was previously visualized through preoperative 3-D imaging. The leg was elevated, and a tourniquet was applied and inflated. A lateral parapatellar approach was used to isolate the distal femoral physis anteriorly because the bone bridge was centered just lateral to the central portion of the distal femoral physis. A Kirschner wire was placed in the center of the bridge under anteroposterior and lateral fluoroscopic imaging (Figures 3A-3E). 

OUTCOME

The patient healed uneventfully, and early range-of-motion exercises were started 6 weeks postoperatively. At 6-month follow-up, his leg-length discrepancy was 2.7 cm, and the bone bridge did not recur. At 3-year follow-up, his leg-length discrepancy was 3.0 cm, and the bone bridge did not recur. Over the 3 years postoperatively, the patient exhibited 9.8 cm of growth on his operative side and 9.5 cm on his nonoperative side (Figure 5). 

DISCUSSION

Given the considerable growth potential of the distal femoral physis,^1,14-16 an injury to the distal femoral physis and the formation of a physeal bone bridge can have a profound effect on a young patient in terms of leg-length discrepancy and angular deformity. Fracture from trauma or infection is a common cause of physeal bone bridges.^6,17-19 The etiology of our patient’s distal femoral physeal bone bridge is idiopathic, which is considerably less common than other etiologies, and the incidence of idiopathic physeal bone bridge formation is not well established in the literature. Hresko and Kasser²¹ identified atraumatic physeal bone bridge formations in 7 patients. Among the 13 patients with physeal bone bridges described by Broughton and colleagues,²⁰ the cause of bridge formation is unknown in 1.

Physeal bone bridges that form centrally are particularly challenging because they are difficult to visualize through a peripheral approach. A number of methods for resecting central physeal bone bridges have been described. These methods have varying degrees of success. In 1981, Langenskiöld⁷ first described the creation of a metaphyseal mirror and the use of a dental mirror for visualization. This technique, however, yielded unfavorable results in 16% of patients. Williamson and Staheli⁹ reported poor results in 23% of patients. Loraas and Schmale⁴ described the use of an endoscope, termed an osteoscope, for visualization, citing advantages of superior illumination and potential for image magnification and capture. Marsh and Polzhofer⁸ also showed this technique to have low morbidity but poor results in 13% of patients, whereas Moreta and colleagues¹⁰ reported poor results in 2 out of 5 patients. The rate of poor results of these methods may be related to the technical difficulty of using dental mirrors and arthroscopes and can be improved by highly efficient direct methods with improved visualization, such as the method described in this article.

Continue to: Proper imaging is necessary for...

Proper imaging is necessary for the accurate quantification of bone bridges to determine resectability and to identify the best surgical approach to resection. MRI with software for the generation of 3-D physeal maps is a reproducible method with good interobserver reliability.^22,23 Intraoperative computer-assisted imaging also is beneficial for determining the extent and location of the resection to ensure complete bone bridge removal.²⁴

To our knowledge, a direct approach through parapatellar arthrotomy for the resection of a centrally located distal femoral physeal bone bridge has not been previously described. This novel technique provided direct access to the physeal bone bridge and was performed without injuring the adjacent physeal cartilage in the medial and lateral columns of the distal femur, which may grow normally in the absence of the bridge. Instead of using a lateral or medial approach with a metaphyseal window,⁴ we directly approached this central bar through a parapatellar approach and were able to completely resect it under direct visualization. This obviated the need for an arthroscope or dental mirror. To remove the entire physeal bone bridge, we needed to resect completely from the anterior cortex to the posterior cortex. Although this technique potentially increased the risk of iatrogenic fracture, we believed that this risk would not differ greatly from that of disrupting the medial or lateral metaphysis and would be more stable with either axial and torsion load. At 3-year follow-up, the patient exhibited restored normal growth in his operative limb relative to that in his nonoperative limb, had not developed angular deformity, and had maintained his previously developed limb-length discrepancy that could be corrected with the epiphysiodesis of his opposite limb at a later date.

The limitations to this technique include the fact that it may be most effective with small-to moderate-sized central physeal bone bridges, although resection has shown good results with up to 70% physeal involvement.⁸ In this patient, the bone bridge was moderately sized (30% of the physis), centrally located, and clearly visible on fluoroscopy. These characteristics increased the technical safety and ease of the procedure. The resection of large, peripheral bridges may destabilize the distal femur. The destabilization of the distal femur, in turn, can lead to fracture. Patellofemoral mechanics may also be affected during the treatment of distal femoral physeal bone bridges. This patient has not experienced any patellofemoral dysfunction or symptoms. Given the patient’s age and significant amount of remaining growth, he will need close monitoring until he reaches skeletal maturity.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

The lateral tibial eminence shares a close relationship with the anterior root of the lateral meniscus. Limited studies have reported traumatic injury to the anterior meniscal roots in the setting of tibial eminence fractures, and reported rates of occurrence of concomitant meniscal and chondral injuries vary widely. The purpose of this article is to describe the case of a 28-year-old woman who had a complete avulsion of the anterolateral meniscal root caused by a tibial eminence fracture with resultant malunion and root displacement. The anterolateral meniscal root was anatomically repaired following arthroscopic resection of the malunited fragment.

The lateral tibial eminence is intimately associated with the root attachment of the anterior horn of the lateral meniscus.^1-3 Previous studies have demonstrated both the close proximity of the anterior cruciate ligament (ACL) insertion to the meniscal roots and the potential for disruption in surgical interventions, such as tibial tunnel drilling in ACL reconstruction or placement of intramedullary tibial nails.^4-6 The meniscal roots play a crucial role in force distribution, and disruption of these structures has been shown to significantly increase joint contact forces. Despite the deleterious effects of this injury, limited studies have reported on traumatic injury to the meniscal roots in the setting of tibial eminence fractures.

Reported rates of occurrence of concomitant meniscal and chondral injuries occurring with tibial eminence fractures vary widely, ranging from <5% to 40%.^7,8 Although fractures to the tibial eminence are more common in children, an association between these injuries and concomitant soft tissue injuries, including meniscal, chondral, and collateral ligament injuries, in the adult population has been reported.⁷ Monto and Cameron-Donaldson⁸ used magnetic resonance imaging (MRI) to evaluate tibial eminence fractures in adults and found that 23% of study subjects had associated medial meniscus tears and 18% had lateral meniscus tears. In a similar study, Ishibashi and colleagues⁹ found that 25% of tibial eminence fractures were associated with lateral meniscus tears and 16% with medial meniscus tears.

These studies demonstrate the potential for meniscus injuries during tibial eminence fractures. However, the authors are unaware of any reports of complete tearing of the anterior horn of the lateral meniscus in association with this injury. This is an important injury to recognize and identify intraoperatively because an injury of this nature could potentially compromise the mechanical loading patterns and health of the articular cartilage of the lateral compartment of the knee. The purpose of this article is to describe a complete avulsion of the anterolateral meniscal root due to a tibial eminence fracture with resultant malunion and displacement of the root in a nonanatomical position. The patient provided written informed consent for print and electronic publication of this case report.

Continue to: A 28-year-old active woman...

CASE

A 28-year-old active woman presented to our clinic 22 months after sustaining a right knee tibial eminence fracture that was initially treated with extension immobilization, which resulted in a fibrous malunion. She subsequently sustained a second injury resulting in displacement of the malunion fracture fragment, and was treated at another institution 10 months prior to presentation at our clinic with arthroscopic reduction and internal fixation with a cannulated screw and washer of the tibial eminence fracture. This was followed by hardware removal 6 months prior to her office visit at our clinic. At presentation, she reported worsening right knee pain, mechanical symptoms, and loss of both flexion and extension compared with her uninjured knee. Conservative management, including activity modification, extensive physical therapy, and anti-inflammatory medication following her most recent procedure, had not resulted in improvement of her symptoms.

Physical examination revealed significantly reduced knee flexion and extension (+15°-120° on the affected side compared with 5° of hyperextension to 130° flexion of the contralateral knee). Ligamentous examination demonstrated no laxity with varus or valgus stress at 0° to 30° of flexion, negative posterior drawer, and a Grade 2 Lachman and positive pivot shift. She also exhibited pain with attempted right knee terminal extension. Radiographs and computed tomography scans were obtained and reviewed. They revealed a malunited tibial eminence fracture (Figures 1A-1D).  

Arthroscopic assessment of the right knee demonstrated the large osseous fragment located in the anterolateral aspect of the joint with the displaced anterior horn of the lateral meniscus attached as well as significant anterior impingement limiting knee extension. Probing of the anterolateral meniscal root in the lateral compartment showed abundant surrounding scar tissue with an abnormal attachment, representing a chronic root avulsion. A mechanical shaver was used to débride the scar tissue and expose the malunited fragment, followed by complete osseous fragment excision with a high-speed burr (Figure 3). 

A soft tissue anterolateral meniscal root repair was performed by creating a 2-cm to 3-cm incision on the anterolateral tibia, just distal to the medial aspect of the Gerdy tubercle. To best restore the footprint of the repair and increase the potential for biologic healing, 2 transtibial tunnels were created at the location of the root attachment. An ACL aiming device with a cannulated sleeve was used to drill 2 bony tunnels approximately 5 mm apart, exiting at the anatomic root footprint. The drill pins were removed, leaving the 2 cannulas in place for later suture passage. A suture-passing device was used to pass 2 separate sutures through the detached meniscal root. 

Continue to: Postoperatively, the patient was placed...

Postoperatively, the patient was placed on a non-weight-bearing protocol for her operative lower extremity for 6 weeks. A brace locked in extension was used for the same period of time (being removed only for physical therapy exercises). Enoxaparin was used for the first 2 weeks for deep vein thrombosis prophylaxis, followed by aspirin for an additional 4 weeks. Physical therapy was started on postoperative day 1 to begin working on early passive ROM exercises. Knee flexion was limited to 0° to 90° of flexion for the first 2 weeks and then progressed as tolerated.

DISCUSSION

This article describes a rare case of a patient with lateral meniscal anterior root avulsion in the setting of a tibial eminence fracture with subsequent malunion and root displacement. In a case such as this, delineation of the true extent of the injury is difficult because the anterior meniscal root can be torn, displaced, and nonanatomically scarred to surrounding soft tissues, making MRI interpretation challenging. Clinically, patients can present with a wide range of symptoms, including pain, mechanical symptoms, instability, and loss of knee motion.¹⁰

The anterior root of the lateral meniscus has been reported to be attached anterior to the lateral tibial eminence and adjacent to the insertion of the ACL. Fibrous connections extending from the anterior horn of the lateral meniscus attachment to the lateral tibial eminence are constant.¹¹ Furumatsu and colleagues¹² demonstrated the existence of dense fibers linking the anterior root of the lateral meniscus with the lateral aspect of the ACL tibial insertion. Acknowledging the close relationship of these structures is key to comprehending the importance of evaluating the anterior horn of the lateral meniscus in cases of tibial eminence fractures at the initial time of injury. Failure to diagnose this pathology can lead to poor clinical outcomes and early degenerative changes of the knee.

Tibial intercondylar eminence avulsion fractures are most likely to occur in children and adolescents, and are equivalent to an ACL tear in adults.¹³ When tibial eminence fractures occur in an older cohort, they are often combined with lesions of the menisci, capsule, or collateral ligaments.¹⁴ The initial injury in our patient demonstrated concomitant anterior root injury that progressed with time to nonanatomical healing of the root, leading to altered biomechanics. Surgical techniques available for meniscal root repair are broadly divided into transosseous suture repairs and suture anchor repairs.¹⁰ The transtibial pullout technique using 2 transtibial bone tunnels as described in this report is the senior author’s (RFL) preference because it provides a strong construct with minimal displacement of the repaired meniscus.^15-17

This article describes a complete avulsion of the anterolateral meniscal root caused by a tibial eminence fracture with resultant malunion and displacement of the root in a nonanatomic position. Anterior meniscal root tears have been reported to result in altered biomechanics and force transmission across the knee, and therefore, anatomic repair of the anterior root is indicated.

ABSTRACT

The lateral tibial eminence shares a close relationship with the anterior root of the lateral meniscus. Limited studies have reported traumatic injury to the anterior meniscal roots in the setting of tibial eminence fractures, and reported rates of occurrence of concomitant meniscal and chondral injuries vary widely. The purpose of this article is to describe the case of a 28-year-old woman who had a complete avulsion of the anterolateral meniscal root caused by a tibial eminence fracture with resultant malunion and root displacement. The anterolateral meniscal root was anatomically repaired following arthroscopic resection of the malunited fragment.

The lateral tibial eminence is intimately associated with the root attachment of the anterior horn of the lateral meniscus.^1-3 Previous studies have demonstrated both the close proximity of the anterior cruciate ligament (ACL) insertion to the meniscal roots and the potential for disruption in surgical interventions, such as tibial tunnel drilling in ACL reconstruction or placement of intramedullary tibial nails.^4-6 The meniscal roots play a crucial role in force distribution, and disruption of these structures has been shown to significantly increase joint contact forces. Despite the deleterious effects of this injury, limited studies have reported on traumatic injury to the meniscal roots in the setting of tibial eminence fractures.

Reported rates of occurrence of concomitant meniscal and chondral injuries occurring with tibial eminence fractures vary widely, ranging from <5% to 40%.^7,8 Although fractures to the tibial eminence are more common in children, an association between these injuries and concomitant soft tissue injuries, including meniscal, chondral, and collateral ligament injuries, in the adult population has been reported.⁷ Monto and Cameron-Donaldson⁸ used magnetic resonance imaging (MRI) to evaluate tibial eminence fractures in adults and found that 23% of study subjects had associated medial meniscus tears and 18% had lateral meniscus tears. In a similar study, Ishibashi and colleagues⁹ found that 25% of tibial eminence fractures were associated with lateral meniscus tears and 16% with medial meniscus tears.

These studies demonstrate the potential for meniscus injuries during tibial eminence fractures. However, the authors are unaware of any reports of complete tearing of the anterior horn of the lateral meniscus in association with this injury. This is an important injury to recognize and identify intraoperatively because an injury of this nature could potentially compromise the mechanical loading patterns and health of the articular cartilage of the lateral compartment of the knee. The purpose of this article is to describe a complete avulsion of the anterolateral meniscal root due to a tibial eminence fracture with resultant malunion and displacement of the root in a nonanatomical position. The patient provided written informed consent for print and electronic publication of this case report.

Continue to: A 28-year-old active woman...

CASE

A 28-year-old active woman presented to our clinic 22 months after sustaining a right knee tibial eminence fracture that was initially treated with extension immobilization, which resulted in a fibrous malunion. She subsequently sustained a second injury resulting in displacement of the malunion fracture fragment, and was treated at another institution 10 months prior to presentation at our clinic with arthroscopic reduction and internal fixation with a cannulated screw and washer of the tibial eminence fracture. This was followed by hardware removal 6 months prior to her office visit at our clinic. At presentation, she reported worsening right knee pain, mechanical symptoms, and loss of both flexion and extension compared with her uninjured knee. Conservative management, including activity modification, extensive physical therapy, and anti-inflammatory medication following her most recent procedure, had not resulted in improvement of her symptoms.

Physical examination revealed significantly reduced knee flexion and extension (+15°-120° on the affected side compared with 5° of hyperextension to 130° flexion of the contralateral knee). Ligamentous examination demonstrated no laxity with varus or valgus stress at 0° to 30° of flexion, negative posterior drawer, and a Grade 2 Lachman and positive pivot shift. She also exhibited pain with attempted right knee terminal extension. Radiographs and computed tomography scans were obtained and reviewed. They revealed a malunited tibial eminence fracture (Figures 1A-1D).  

Arthroscopic assessment of the right knee demonstrated the large osseous fragment located in the anterolateral aspect of the joint with the displaced anterior horn of the lateral meniscus attached as well as significant anterior impingement limiting knee extension. Probing of the anterolateral meniscal root in the lateral compartment showed abundant surrounding scar tissue with an abnormal attachment, representing a chronic root avulsion. A mechanical shaver was used to débride the scar tissue and expose the malunited fragment, followed by complete osseous fragment excision with a high-speed burr (Figure 3). 

A soft tissue anterolateral meniscal root repair was performed by creating a 2-cm to 3-cm incision on the anterolateral tibia, just distal to the medial aspect of the Gerdy tubercle. To best restore the footprint of the repair and increase the potential for biologic healing, 2 transtibial tunnels were created at the location of the root attachment. An ACL aiming device with a cannulated sleeve was used to drill 2 bony tunnels approximately 5 mm apart, exiting at the anatomic root footprint. The drill pins were removed, leaving the 2 cannulas in place for later suture passage. A suture-passing device was used to pass 2 separate sutures through the detached meniscal root. 

Continue to: Postoperatively, the patient was placed...

Postoperatively, the patient was placed on a non-weight-bearing protocol for her operative lower extremity for 6 weeks. A brace locked in extension was used for the same period of time (being removed only for physical therapy exercises). Enoxaparin was used for the first 2 weeks for deep vein thrombosis prophylaxis, followed by aspirin for an additional 4 weeks. Physical therapy was started on postoperative day 1 to begin working on early passive ROM exercises. Knee flexion was limited to 0° to 90° of flexion for the first 2 weeks and then progressed as tolerated.

DISCUSSION

This article describes a rare case of a patient with lateral meniscal anterior root avulsion in the setting of a tibial eminence fracture with subsequent malunion and root displacement. In a case such as this, delineation of the true extent of the injury is difficult because the anterior meniscal root can be torn, displaced, and nonanatomically scarred to surrounding soft tissues, making MRI interpretation challenging. Clinically, patients can present with a wide range of symptoms, including pain, mechanical symptoms, instability, and loss of knee motion.¹⁰

The anterior root of the lateral meniscus has been reported to be attached anterior to the lateral tibial eminence and adjacent to the insertion of the ACL. Fibrous connections extending from the anterior horn of the lateral meniscus attachment to the lateral tibial eminence are constant.¹¹ Furumatsu and colleagues¹² demonstrated the existence of dense fibers linking the anterior root of the lateral meniscus with the lateral aspect of the ACL tibial insertion. Acknowledging the close relationship of these structures is key to comprehending the importance of evaluating the anterior horn of the lateral meniscus in cases of tibial eminence fractures at the initial time of injury. Failure to diagnose this pathology can lead to poor clinical outcomes and early degenerative changes of the knee.

Tibial intercondylar eminence avulsion fractures are most likely to occur in children and adolescents, and are equivalent to an ACL tear in adults.¹³ When tibial eminence fractures occur in an older cohort, they are often combined with lesions of the menisci, capsule, or collateral ligaments.¹⁴ The initial injury in our patient demonstrated concomitant anterior root injury that progressed with time to nonanatomical healing of the root, leading to altered biomechanics. Surgical techniques available for meniscal root repair are broadly divided into transosseous suture repairs and suture anchor repairs.¹⁰ The transtibial pullout technique using 2 transtibial bone tunnels as described in this report is the senior author’s (RFL) preference because it provides a strong construct with minimal displacement of the repaired meniscus.^15-17

This article describes a complete avulsion of the anterolateral meniscal root caused by a tibial eminence fracture with resultant malunion and displacement of the root in a nonanatomic position. Anterior meniscal root tears have been reported to result in altered biomechanics and force transmission across the knee, and therefore, anatomic repair of the anterior root is indicated.

ABSTRACT

The lateral tibial eminence shares a close relationship with the anterior root of the lateral meniscus. Limited studies have reported traumatic injury to the anterior meniscal roots in the setting of tibial eminence fractures, and reported rates of occurrence of concomitant meniscal and chondral injuries vary widely. The purpose of this article is to describe the case of a 28-year-old woman who had a complete avulsion of the anterolateral meniscal root caused by a tibial eminence fracture with resultant malunion and root displacement. The anterolateral meniscal root was anatomically repaired following arthroscopic resection of the malunited fragment.

The lateral tibial eminence is intimately associated with the root attachment of the anterior horn of the lateral meniscus.^1-3 Previous studies have demonstrated both the close proximity of the anterior cruciate ligament (ACL) insertion to the meniscal roots and the potential for disruption in surgical interventions, such as tibial tunnel drilling in ACL reconstruction or placement of intramedullary tibial nails.^4-6 The meniscal roots play a crucial role in force distribution, and disruption of these structures has been shown to significantly increase joint contact forces. Despite the deleterious effects of this injury, limited studies have reported on traumatic injury to the meniscal roots in the setting of tibial eminence fractures.

Reported rates of occurrence of concomitant meniscal and chondral injuries occurring with tibial eminence fractures vary widely, ranging from <5% to 40%.^7,8 Although fractures to the tibial eminence are more common in children, an association between these injuries and concomitant soft tissue injuries, including meniscal, chondral, and collateral ligament injuries, in the adult population has been reported.⁷ Monto and Cameron-Donaldson⁸ used magnetic resonance imaging (MRI) to evaluate tibial eminence fractures in adults and found that 23% of study subjects had associated medial meniscus tears and 18% had lateral meniscus tears. In a similar study, Ishibashi and colleagues⁹ found that 25% of tibial eminence fractures were associated with lateral meniscus tears and 16% with medial meniscus tears.

These studies demonstrate the potential for meniscus injuries during tibial eminence fractures. However, the authors are unaware of any reports of complete tearing of the anterior horn of the lateral meniscus in association with this injury. This is an important injury to recognize and identify intraoperatively because an injury of this nature could potentially compromise the mechanical loading patterns and health of the articular cartilage of the lateral compartment of the knee. The purpose of this article is to describe a complete avulsion of the anterolateral meniscal root due to a tibial eminence fracture with resultant malunion and displacement of the root in a nonanatomical position. The patient provided written informed consent for print and electronic publication of this case report.

Continue to: A 28-year-old active woman...

CASE

A 28-year-old active woman presented to our clinic 22 months after sustaining a right knee tibial eminence fracture that was initially treated with extension immobilization, which resulted in a fibrous malunion. She subsequently sustained a second injury resulting in displacement of the malunion fracture fragment, and was treated at another institution 10 months prior to presentation at our clinic with arthroscopic reduction and internal fixation with a cannulated screw and washer of the tibial eminence fracture. This was followed by hardware removal 6 months prior to her office visit at our clinic. At presentation, she reported worsening right knee pain, mechanical symptoms, and loss of both flexion and extension compared with her uninjured knee. Conservative management, including activity modification, extensive physical therapy, and anti-inflammatory medication following her most recent procedure, had not resulted in improvement of her symptoms.

Physical examination revealed significantly reduced knee flexion and extension (+15°-120° on the affected side compared with 5° of hyperextension to 130° flexion of the contralateral knee). Ligamentous examination demonstrated no laxity with varus or valgus stress at 0° to 30° of flexion, negative posterior drawer, and a Grade 2 Lachman and positive pivot shift. She also exhibited pain with attempted right knee terminal extension. Radiographs and computed tomography scans were obtained and reviewed. They revealed a malunited tibial eminence fracture (Figures 1A-1D).  

Arthroscopic assessment of the right knee demonstrated the large osseous fragment located in the anterolateral aspect of the joint with the displaced anterior horn of the lateral meniscus attached as well as significant anterior impingement limiting knee extension. Probing of the anterolateral meniscal root in the lateral compartment showed abundant surrounding scar tissue with an abnormal attachment, representing a chronic root avulsion. A mechanical shaver was used to débride the scar tissue and expose the malunited fragment, followed by complete osseous fragment excision with a high-speed burr (Figure 3). 

A soft tissue anterolateral meniscal root repair was performed by creating a 2-cm to 3-cm incision on the anterolateral tibia, just distal to the medial aspect of the Gerdy tubercle. To best restore the footprint of the repair and increase the potential for biologic healing, 2 transtibial tunnels were created at the location of the root attachment. An ACL aiming device with a cannulated sleeve was used to drill 2 bony tunnels approximately 5 mm apart, exiting at the anatomic root footprint. The drill pins were removed, leaving the 2 cannulas in place for later suture passage. A suture-passing device was used to pass 2 separate sutures through the detached meniscal root. 

Continue to: Postoperatively, the patient was placed...

Postoperatively, the patient was placed on a non-weight-bearing protocol for her operative lower extremity for 6 weeks. A brace locked in extension was used for the same period of time (being removed only for physical therapy exercises). Enoxaparin was used for the first 2 weeks for deep vein thrombosis prophylaxis, followed by aspirin for an additional 4 weeks. Physical therapy was started on postoperative day 1 to begin working on early passive ROM exercises. Knee flexion was limited to 0° to 90° of flexion for the first 2 weeks and then progressed as tolerated.

DISCUSSION

This article describes a rare case of a patient with lateral meniscal anterior root avulsion in the setting of a tibial eminence fracture with subsequent malunion and root displacement. In a case such as this, delineation of the true extent of the injury is difficult because the anterior meniscal root can be torn, displaced, and nonanatomically scarred to surrounding soft tissues, making MRI interpretation challenging. Clinically, patients can present with a wide range of symptoms, including pain, mechanical symptoms, instability, and loss of knee motion.¹⁰

The anterior root of the lateral meniscus has been reported to be attached anterior to the lateral tibial eminence and adjacent to the insertion of the ACL. Fibrous connections extending from the anterior horn of the lateral meniscus attachment to the lateral tibial eminence are constant.¹¹ Furumatsu and colleagues¹² demonstrated the existence of dense fibers linking the anterior root of the lateral meniscus with the lateral aspect of the ACL tibial insertion. Acknowledging the close relationship of these structures is key to comprehending the importance of evaluating the anterior horn of the lateral meniscus in cases of tibial eminence fractures at the initial time of injury. Failure to diagnose this pathology can lead to poor clinical outcomes and early degenerative changes of the knee.

Tibial intercondylar eminence avulsion fractures are most likely to occur in children and adolescents, and are equivalent to an ACL tear in adults.¹³ When tibial eminence fractures occur in an older cohort, they are often combined with lesions of the menisci, capsule, or collateral ligaments.¹⁴ The initial injury in our patient demonstrated concomitant anterior root injury that progressed with time to nonanatomical healing of the root, leading to altered biomechanics. Surgical techniques available for meniscal root repair are broadly divided into transosseous suture repairs and suture anchor repairs.¹⁰ The transtibial pullout technique using 2 transtibial bone tunnels as described in this report is the senior author’s (RFL) preference because it provides a strong construct with minimal displacement of the repaired meniscus.^15-17

This article describes a complete avulsion of the anterolateral meniscal root caused by a tibial eminence fracture with resultant malunion and displacement of the root in a nonanatomic position. Anterior meniscal root tears have been reported to result in altered biomechanics and force transmission across the knee, and therefore, anatomic repair of the anterior root is indicated.

ABSTRACT

Outcome instruments have become an essential part of the evaluation of functional recovery after anterior cruciate ligament (ACL) reconstruction. Although the clinical examination provides important objective information to assess graft integrity, stability, range of motion, and strength, these measurements do not take the patient’s perception into account. There are many knee outcome instruments, and it is challenging for surgeons to understand how to interpret clinical research and utilize these measures in a practical way. The purpose of this review is to provide an overview of the most commonly used outcome measures in patients undergoing ACL reconstruction and to examine and compare the psychometric performance (validity, reliability, responsiveness) of these measurement tools.

Anterior cruciate ligament (ACL) reconstruction is one of the most common elective orthopedic procedures.¹ Despite advances in surgical techniques, ACL reconstruction is associated with a lengthy recovery time, decreased performance, and increased rate of reinjury.² Patients undergoing ACL reconstruction are often active individuals who participate in demanding activities, and accurate assessment of their recovery helps to guide recovery counseling. In addition to objective clinical outcomes measured through physical examination, patient-reported outcome (PRO) instruments add the patient’s perspective, information critical in determining a successful outcome. A variety of outcome instruments have been used and validated for patients with ACL tears. It is important for orthopedic surgeons to know the advantages and disadvantages of each outcome tool in order to interpret clinical studies and assess postoperative patients.

Over the last 10 years, there has been an increase in the number of knee instruments and rating scales designed to measure PROs, with >54 scores designed for the ACL-deficient knee.³ No standardized instrument is currently universally accepted as superior following ACL reconstruction across the spectrum of patient populations. Clinicians and researchers must carefully consider an outcome instrument’s utility based on specific patient populations in which it has been evaluated. Appropriate selection of outcome measures is of fundamental importance for adequate demonstration of the efficacy and value of treatment interventions, especially in an era of healthcare reform with a focus on providing high-quality and cost-effective care.

The purpose of this review is to highlight current tools used to measure outcomes after ACL reconstruction. Current outcome measures vary widely in regards to their validity, reliability, minimal clinically important difference, and applicability to specific patient populations. We have thus identified the measures most commonly used today in studies and clinical follow-up after ACL reconstruction and their various advantages and limitations. This information may enhance the orthopedic surgeon’s understanding of what outcome measures may be utilized in clinical studies.

Continue to: Patient-Reported Outcome Instruments...

PATIENT-REPORTED OUTCOME INSTRUMENTS

Recently, there has been a transition to increased use of PRO instruments rather than clinician-based postoperative assessment, largely due to the increasing emphasis on patient satisfaction in determining the value of an orthopedic intervention.⁴ PRO instruments are widely used to capture the patient’s perception of general health, quality of life (QOL), daily function, and pain. PRO instruments offer the benefit of allowing patients to subjectively assess their knee function during daily living and sports activities, conveying to the provider the impact of ACL reconstruction on physical, psychological, and social aspects of everyday activities. Furthermore, patient satisfaction has been shown to closely follow outcome scores related to symptoms and function.⁵ A multitude of specific knee-related PRO instruments have been developed and validated to measure outcomes after ACL reconstruction for both research and clinical purposes (Table).

Table. ACL Outcome Measures

Abbreviations: AAOS, American Academy of Orthopaedic Surgeons; ACL, anterior cruciate ligament; ACL-QOL, anterior cruciate ligament quality of life score; CAT, computer-adapting testing; IKDC, International Knee Documentation Committee; KOOS, Knee Injury and Osteoarthritis Outcome Score; OA, osteoarthritis; PF, physical function; PROMIS, Patient-Reported Outcome Measurement Information System; Ref, references; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index.

MEASUREMENT PROPERTIES

In general, clinicians and investigators should use health-related outcome measures with established reliability, validity, patient relevance, and responsiveness for assessing the specific condition.⁶

Reliability refers to the degree to which a measurement score is free from random error, reflecting how consistent or reproducible the instrument is when administered under the same testing conditions. Internal consistency, test-retest reliability, and measurement error are measures of reliability. Internal consistency is tested after a single administration and assesses how well items within a scale measure a single underlying dimension, represented using item-total correlation coefficients and Cronbach’s alpha. A Cronbach’s alpha of 0.70 to 0.95 is generally defined as good.⁷ Test-retest reliability is designed to appraise variation over time in stable patients and is represented using the intraclass correlation coefficient (ICC).⁸ An ICC >0.7 is considered acceptable; >0.8, good; and >0.9, excellent.⁹ An aspect of accuracy is whether the scoring system measures the full range of the disease or complaints. The incidence of minimum (floor) and maximum (ceiling) scores can be calculated for outcome scores. An instrument with low floor and ceiling effects, below 10% to 15%, is more inconclusive and can be more reliably used to measure patients at the high and low end of the scoring system.¹⁰

Validity is the ability of an outcome instrument to measure what it is intended to measure. Establishing validity is complex and requires evaluation of several facets, including content validity, construct validity, and criterion validity. Content validity is a relatively subjective judgment explaining the ability of an instrument to assess the critical features of the problem. Construct validity evaluates whether the questionnaire measures what it intends to measure, and is often assessed by correlating scores form one instrument to those from other proven instruments that are already accepted as valid. Finally, criterion validity assesses the correlation between the score and a previously established “gold standard” instrument.

Responsiveness is the ability of the instrument to detect a change or identify improvement or worsening of a clinical condition over time. Most frequently, the effect size (observed change/standard deviation of baseline scores) and standardized response mean (observed change/standard deviation of change) are used as measures of responsiveness. The minimal clinically important difference of an outcome measure is the smallest change in an outcome score that corresponds to a change in patient condition.

Continue to: ACL Outcome Instruments...

ACL OUTCOME INSTRUMENTS

WESTERN ONTARIO AND MCMASTER UNIVERSITIES OSTEOARTHRITIS INDEX (WOMAC LK 3.0)

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC LK 3.0) was developed in 1982 and is a widely used, disease-specific instrument recommended for the evaluation of treatment effects in patients with hip and knee osteoarthritis.¹¹ Available in more than 80 languages, it is a self-administered, generic health status questionnaire developed to assess pain, function, and stiffness in daily living, taking respondents between 3 to 7.5 minutes for completion.¹² Using visual analog scales, the 24 items probe the 3 subscales: pain (5 items), stiffness (2 items), and functional difficulty (17 items). Scores are calculated for each dimension, and the total score is normalized to a 100-point scale, with 0 indicating severe symptoms and 100 indicating no symptoms and higher function. The WOMAC score can also be calculated from the Knee Injury and Osteoarthritis Outcome Score (KOOS). The WOMAC questionnaire is well recognized for its good validity, reliability, and responsiveness, and is the most commonly used outcome measure for osteoarthritis.^13-15 Considering its focus on older patients with osteoarthritis, it may not be appropriate for use in a young and active population.

KNEE INJURY AND OSTEOARTHRITIS OUTCOME SCORE (KOOS)

The KOOS is a knee-specific questionnaire developed as an extension of the WOMAC to evaluate the functional status and QOL of patients with any type of knee injury who are at an increased risk of developing osteoarthritis.¹⁶ The patient-based questionnaire is available in over 30 languages and covers both the short- and long-term consequences of an injury of the knee causing traumatic damage to cartilage, ligaments, and menisci. The KOOS is 42 items graded on a 5-point Likert scale, covering 5 subscales: pain (9 items), symptoms (7 items), function in activities of daily living (17 items), function in sports/recreation (5 items), and knee-related QOL (4 items). The questionnaire is self-administered and takes about 10 minutes to complete. Scores are calculated for each dimension, and the total score is transformed to a 0 to 100 scale, with 0 representing severe knee problems and 100 representing no knee problems and better outcome. An advantage of the KOOS is that it evaluates both knee injuries and osteoarthritis; therefore, it is arguably more suitable for evaluating patients over the long-term. The KOOS has been validated for several orthopedic interventions, including ACL reconstruction and rehabilitation^16,17 as well as meniscectomy¹⁸ and total knee replacement.¹⁹ Population-based reference data for the adult population according to age and gender have also been established.²⁰ The KOOS is increasingly utilized in clinical studies on ACL reconstruction.^21-25 The questions of the WOMAC were retained so that a WOMAC score might be calculated separately and compared with the KOOS score.²⁶

PATIENT-REPORTED OUTCOMES INFORMATION SYSTEM (PROMIS)

Since 2004, The National Institutes of Health (NIH) has funded the development of the Patient-Reported Outcome Measurement Information System (PROMIS), a set of flexible tools that reliably and validly measure PROs. The PROMIS consists of a library of question banks that has been developed and operated by a network of National Institutes of Health-funded research sites and coordinating centers and covers many different health domains including pain, fatigue, anxiety, depression, social functioning, physical functioning, and sleep. PROMIS items are developed using Item Response Theory (IRT), wherein the answer to any individual item has a known mathematical probability of predicting the test taker’s overall measurement of the specific trait being tested. This is commonly administered using computer-adaptive testing (CAT), which presents to the test taker an initial item, scores the response to that item, and from the response then presents the most informative second item, and so forth until a predefined level of precision is reached. Because the items are individually validated, they can be used alone or in any combination, a feature that distinguishes the PROMIS from traditional fixed-length PRO instruments that require the completion of an instrument in its entirety to be valid.²⁷ In recent years, orthopedic research has been published with PROMIS physical function (PF) scores as primary outcome measures.^28-30 The PF item bank includes 124 items measuring upper extremity, lower extremity, central and instrumental activities of daily living. PF can be completed as a short form (SF) with a set number of questions or utilizing CAT and evaluates self-reported function and physical activity. An advantage is its ease of use and potential to minimize test burden with very few questions, often as little as 4 items, as compared to other traditional PROMs.³¹

Previously published work has demonstrated that, in patients undergoing meniscal surgery, the PROMIS PF CAT maintains construct validity and correlates well with currently used knee outcome instruments, including KOOS.²⁸ Work by the same group looking at the performance of the PROMIS PF CAT in patients indicated for ACL reconstruction shows that the PROMIS PF CAT correlates well with other PRO instruments for patients with ACL injuries, (SF-36 PF [r = 0.82, P < 0.01], KOOS Sport [r = 0.70, P < 0.01], KOOS ADL [r = 0.74, P < 0.01]), does not have floor or ceiling effects in this relatively young and healthy population, and has a low test burden.^32,33 Papuga and colleagues³³ also compared the International Knee Documentation Committee (IKDC) and PROMIS PF CAT on 106 subjects after ACL reconstruction and found good correlation.

Continue to: Quality of Life Outcome Measure...

QUALITY OF LIFE OUTCOME MEASURE FOR ACL DEFICIENCY (ACL-QOL)

The ACL-QOL Score was developed in 1998 as a disease-specific measure for patients with chronic ACL deficiency.³⁴ This scale consists of 32 separate items in 31 visual analog questions regarding symptoms and physical complaints, work-related concerns, recreational activities and sport participation or competition, lifestyle, and social and emotional health status relating to the knee. The raw score is transformed into a 0- to 100-point scale, with higher scores indicating a better outcome. The scale is valid, reliable, and responsive for patients with ACL insufficiency,^35,36 and is not applicable to other disorders of the knee. We recommend the ACL-QOL questionnaire be used in conjunction with other currently available objective and functional outcome measures.

CINCINNATI KNEE RATING SYSTEM

The Cincinnati Knee Rating System (CKRS) was first described in 1983 and was modified to include occupational activities, athletic activities, symptoms, and functional limitations.^37,38 There are 11 components, measuring symptoms and disability in sports activity, activities of daily living function, occupational rating, as well as sections that measure physical examination, laxity of the knee, and radiographic evidence of degenerative joint disease.³⁹ The measure is scored on a 100-point scale, with higher scores indicating better outcomes. Scores have been shown to be lower as compared with other outcome measures assessing the same clinical condition.^40,41 Barber-Westin and colleagues³⁹ confirmed the reliability, validity, and responsiveness of the CKRS by testing 350 subjects with and without knee ligament injuries. In 2001, Marx⁴² tested the CKRS subjective form for reliability, validity, and responsiveness and found it to be acceptable for clinical research.

LYSHOLM KNEE SCORE

The Lysholm Knee Score was published in 1982 and modified in 1985, consisting of an 8-question survey that evaluates outcomes after knee ligament surgery. Items include pain, instability, locking, squatting, limping, support usage, swelling, and stair-climbing ability, with pain and instability carrying the highest weight.⁴³ It is scored on a scale of 0 to 100, with high scores indicating higher functioning and fewer symptoms. It has been validated in patients with ACL injuries and meniscal injuries.⁴⁴ Although it is widely used to measure outcomes after ACL reconstruction,⁴⁵ it has received criticism in the evaluation of patients with other knee conditions.⁴⁶ The main advantage of the Lysholm Knee Score is its ability to note changes in activity in the same patient across different time periods (responsiveness). A limitation of the Lysholm Knee Score is that it does not measure the domains of functioning in daily activities, sports, and recreational activities. The Lysholm scoring system’s test-retest reliability and construct validity have been evaluated,^42,43,46 although there has been some concern regarding a ceiling effect and its validity, sensitivity, and reliability has been questioned.⁴⁷ Therefore, it is advised that this score be used in conjunction with other PRO scores.

INTERNATIONAL KNEE DOCUMENTATION COMMITTEE (IKDC) SUBJECTIVE KNEE FORM

In 1987, members of the European Society for Knee Surgery and Arthroscopy and the American Orthopaedic Society for Sports Medicine formed the IKDC to develop a standardized method for evaluating knee injuries and treatment. The IKDC Subjective Knee Evaluation Form was initially published in 1993, and in 2001 the form was revised by the American Orthopaedic Society for Sports Medicine to become a knee-specific assessment tool rather than a disease or condition-specific tool.⁴⁸ The IKDC subjective form is an 18-question, knee-specific survey designed to detect improvement or deterioration in symptoms, function, and ability to participate in sports activities experienced by patients following knee surgery or other interventions. The individual items are summed and transformed into a 0- to 100-point scale, with high scores representing higher levels of function and minimal symptoms. The IKDC is utilized to assess a variety of knee conditions including ligament, meniscus, articular cartilage, osteoarthritis, and patellofemoral pain.^48,49 Thus, this form can be used to assess any condition involving the knee and allow comparison between groups with different diagnoses. The IKDC has been validated for an ACL reconstruction population,⁴⁷ has been used to assess outcomes in recent clinical studies on ACL reconstruction,^50,51 and is one of the most frequently used measures for patients with ACL deficiency.³ The validity, responsiveness, and reliability of the IKDC subjective form has been confirmed for both adult and adolescent populations.^48,49,52-54

TEGNER ACTIVITY SCORES

The Tegner activity score was developed in 1985 and was designed to provide an objective value for a patient’s activity level.⁴⁴ This scale was developed to complement the Lysholm score. It consists of 1 sport-specific activity level question on a 0 to 10 scale that evaluates an individual’s ability to compete in a sporting activity. Scores between 1 and 5 represent work or recreational sports. Scores >5 represent higher-level recreational and competitive sports. The Tegner activity score is one of the most widely used activity scoring systems for patients with knee disorders,^55,56 commonly utilized with the Lysholm Knee Score.⁴⁴ One disadvantage of the Tegner activity score is that it relates to specific sports rather than functional activities, which limits its generalizability. We are not aware of any studies documenting the reliability or validity of this instrument.

Continue on: Marx Activity Rating Scale...

MARX ACTIVITY RATING SCALE

The Marx activity rating scale was developed to be utilized with other knee rating scales and outcome measures as an activity assessment.⁵⁷ In contrast to the Tegner activity score, the Marx activity rating scale measures function rather than sport-specific activity. The scale is a short, patient-based activity assessment that consists of a 4-question survey evaluating patients’ knee health by recording the frequency and intensity of participation in a sporting activity. Questions are scored from 0 to 4 on the basis of how often the activity is performed. The 4 sections of the Marx scale that are rated include running, cutting, decelerating, and pivoting. This scale has been validated in patients with ACL injuries, chondromalacia patellae, and meniscal lesions.^42,56-58 Acceptable ceiling effects of 3% and floor effects of 8% were noted in the study of ACL-injured patients.⁵⁷

AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS (AAOS) SPORTS KNEE SCALE

The American Academy of Orthopaedic Surgeons (AAOS) Sports Knee Rating Scale consists of 5 parts and 23 items, including a section addressing stiffness, swelling, pain and function (7 questions), locking/catching (4 questions), giving way (4 questions), limitations of activity (4 questions), and pain with activity (4 questions).^59,60 Items may be dropped if patients select particular responses, which can lead to difficulties when using the survey. This scoring system has been found to be satisfactory when all subscales were combined and the mean was calculated.⁴²

DISCUSSION

PRO measures play an increasingly important role in the measurement of success and impact of health care services. Specifically, for ACL reconstruction, patient satisfaction is key for demonstrating the value of operative or other interventions. Selecting a suitable outcome measurement tool can be daunting, as it can be difficult to ascertain which outcome measures are appropriate for the patient or disorder in question. As there is currently no instrument that is universally superior in the evaluation of ACL outcomes, clinicians must consider the specific patient population in which the outcome instrument has been evaluated. Investigators should also use instruments with reported minimal clinically important differences so that variation in scores can be interpreted as either clinically significant or not. When choosing which outcome instrument to use, there is rarely a single appropriate rating system that is entirely comprehensive. In most cases, a general health outcome measure should be used in combination with a condition-specific rating scale. Activity rating scales, such as Marx or Tegner, should be included, especially when evaluating patients with low-activity lifestyles.

CONCLUSION

There are a number of reliable, valid, and responsive outcome measures that can be utilized to evaluate outcomes following ACL reconstruction in an array of patient populations. Outcome measures should be relevant to patients, easy to use, reliable, valid, and responsive to change. By increasing familiarity with these outcome measures, orthopedic surgeons and investigators can develop better studies, interpret data, and implement findings in practice with sound and informed judgment. Future research should focus on identifying the most relevant outcome metrics for assessing function following ACL reconstruction.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Outcome instruments have become an essential part of the evaluation of functional recovery after anterior cruciate ligament (ACL) reconstruction. Although the clinical examination provides important objective information to assess graft integrity, stability, range of motion, and strength, these measurements do not take the patient’s perception into account. There are many knee outcome instruments, and it is challenging for surgeons to understand how to interpret clinical research and utilize these measures in a practical way. The purpose of this review is to provide an overview of the most commonly used outcome measures in patients undergoing ACL reconstruction and to examine and compare the psychometric performance (validity, reliability, responsiveness) of these measurement tools.

Anterior cruciate ligament (ACL) reconstruction is one of the most common elective orthopedic procedures.¹ Despite advances in surgical techniques, ACL reconstruction is associated with a lengthy recovery time, decreased performance, and increased rate of reinjury.² Patients undergoing ACL reconstruction are often active individuals who participate in demanding activities, and accurate assessment of their recovery helps to guide recovery counseling. In addition to objective clinical outcomes measured through physical examination, patient-reported outcome (PRO) instruments add the patient’s perspective, information critical in determining a successful outcome. A variety of outcome instruments have been used and validated for patients with ACL tears. It is important for orthopedic surgeons to know the advantages and disadvantages of each outcome tool in order to interpret clinical studies and assess postoperative patients.

Over the last 10 years, there has been an increase in the number of knee instruments and rating scales designed to measure PROs, with >54 scores designed for the ACL-deficient knee.³ No standardized instrument is currently universally accepted as superior following ACL reconstruction across the spectrum of patient populations. Clinicians and researchers must carefully consider an outcome instrument’s utility based on specific patient populations in which it has been evaluated. Appropriate selection of outcome measures is of fundamental importance for adequate demonstration of the efficacy and value of treatment interventions, especially in an era of healthcare reform with a focus on providing high-quality and cost-effective care.

The purpose of this review is to highlight current tools used to measure outcomes after ACL reconstruction. Current outcome measures vary widely in regards to their validity, reliability, minimal clinically important difference, and applicability to specific patient populations. We have thus identified the measures most commonly used today in studies and clinical follow-up after ACL reconstruction and their various advantages and limitations. This information may enhance the orthopedic surgeon’s understanding of what outcome measures may be utilized in clinical studies.

Continue to: Patient-Reported Outcome Instruments...

PATIENT-REPORTED OUTCOME INSTRUMENTS

Recently, there has been a transition to increased use of PRO instruments rather than clinician-based postoperative assessment, largely due to the increasing emphasis on patient satisfaction in determining the value of an orthopedic intervention.⁴ PRO instruments are widely used to capture the patient’s perception of general health, quality of life (QOL), daily function, and pain. PRO instruments offer the benefit of allowing patients to subjectively assess their knee function during daily living and sports activities, conveying to the provider the impact of ACL reconstruction on physical, psychological, and social aspects of everyday activities. Furthermore, patient satisfaction has been shown to closely follow outcome scores related to symptoms and function.⁵ A multitude of specific knee-related PRO instruments have been developed and validated to measure outcomes after ACL reconstruction for both research and clinical purposes (Table).

Table. ACL Outcome Measures

Abbreviations: AAOS, American Academy of Orthopaedic Surgeons; ACL, anterior cruciate ligament; ACL-QOL, anterior cruciate ligament quality of life score; CAT, computer-adapting testing; IKDC, International Knee Documentation Committee; KOOS, Knee Injury and Osteoarthritis Outcome Score; OA, osteoarthritis; PF, physical function; PROMIS, Patient-Reported Outcome Measurement Information System; Ref, references; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index.

MEASUREMENT PROPERTIES

In general, clinicians and investigators should use health-related outcome measures with established reliability, validity, patient relevance, and responsiveness for assessing the specific condition.⁶

Reliability refers to the degree to which a measurement score is free from random error, reflecting how consistent or reproducible the instrument is when administered under the same testing conditions. Internal consistency, test-retest reliability, and measurement error are measures of reliability. Internal consistency is tested after a single administration and assesses how well items within a scale measure a single underlying dimension, represented using item-total correlation coefficients and Cronbach’s alpha. A Cronbach’s alpha of 0.70 to 0.95 is generally defined as good.⁷ Test-retest reliability is designed to appraise variation over time in stable patients and is represented using the intraclass correlation coefficient (ICC).⁸ An ICC >0.7 is considered acceptable; >0.8, good; and >0.9, excellent.⁹ An aspect of accuracy is whether the scoring system measures the full range of the disease or complaints. The incidence of minimum (floor) and maximum (ceiling) scores can be calculated for outcome scores. An instrument with low floor and ceiling effects, below 10% to 15%, is more inconclusive and can be more reliably used to measure patients at the high and low end of the scoring system.¹⁰

Validity is the ability of an outcome instrument to measure what it is intended to measure. Establishing validity is complex and requires evaluation of several facets, including content validity, construct validity, and criterion validity. Content validity is a relatively subjective judgment explaining the ability of an instrument to assess the critical features of the problem. Construct validity evaluates whether the questionnaire measures what it intends to measure, and is often assessed by correlating scores form one instrument to those from other proven instruments that are already accepted as valid. Finally, criterion validity assesses the correlation between the score and a previously established “gold standard” instrument.

Responsiveness is the ability of the instrument to detect a change or identify improvement or worsening of a clinical condition over time. Most frequently, the effect size (observed change/standard deviation of baseline scores) and standardized response mean (observed change/standard deviation of change) are used as measures of responsiveness. The minimal clinically important difference of an outcome measure is the smallest change in an outcome score that corresponds to a change in patient condition.

Continue to: ACL Outcome Instruments...

ACL OUTCOME INSTRUMENTS

WESTERN ONTARIO AND MCMASTER UNIVERSITIES OSTEOARTHRITIS INDEX (WOMAC LK 3.0)

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC LK 3.0) was developed in 1982 and is a widely used, disease-specific instrument recommended for the evaluation of treatment effects in patients with hip and knee osteoarthritis.¹¹ Available in more than 80 languages, it is a self-administered, generic health status questionnaire developed to assess pain, function, and stiffness in daily living, taking respondents between 3 to 7.5 minutes for completion.¹² Using visual analog scales, the 24 items probe the 3 subscales: pain (5 items), stiffness (2 items), and functional difficulty (17 items). Scores are calculated for each dimension, and the total score is normalized to a 100-point scale, with 0 indicating severe symptoms and 100 indicating no symptoms and higher function. The WOMAC score can also be calculated from the Knee Injury and Osteoarthritis Outcome Score (KOOS). The WOMAC questionnaire is well recognized for its good validity, reliability, and responsiveness, and is the most commonly used outcome measure for osteoarthritis.^13-15 Considering its focus on older patients with osteoarthritis, it may not be appropriate for use in a young and active population.

KNEE INJURY AND OSTEOARTHRITIS OUTCOME SCORE (KOOS)

The KOOS is a knee-specific questionnaire developed as an extension of the WOMAC to evaluate the functional status and QOL of patients with any type of knee injury who are at an increased risk of developing osteoarthritis.¹⁶ The patient-based questionnaire is available in over 30 languages and covers both the short- and long-term consequences of an injury of the knee causing traumatic damage to cartilage, ligaments, and menisci. The KOOS is 42 items graded on a 5-point Likert scale, covering 5 subscales: pain (9 items), symptoms (7 items), function in activities of daily living (17 items), function in sports/recreation (5 items), and knee-related QOL (4 items). The questionnaire is self-administered and takes about 10 minutes to complete. Scores are calculated for each dimension, and the total score is transformed to a 0 to 100 scale, with 0 representing severe knee problems and 100 representing no knee problems and better outcome. An advantage of the KOOS is that it evaluates both knee injuries and osteoarthritis; therefore, it is arguably more suitable for evaluating patients over the long-term. The KOOS has been validated for several orthopedic interventions, including ACL reconstruction and rehabilitation^16,17 as well as meniscectomy¹⁸ and total knee replacement.¹⁹ Population-based reference data for the adult population according to age and gender have also been established.²⁰ The KOOS is increasingly utilized in clinical studies on ACL reconstruction.^21-25 The questions of the WOMAC were retained so that a WOMAC score might be calculated separately and compared with the KOOS score.²⁶

PATIENT-REPORTED OUTCOMES INFORMATION SYSTEM (PROMIS)

Since 2004, The National Institutes of Health (NIH) has funded the development of the Patient-Reported Outcome Measurement Information System (PROMIS), a set of flexible tools that reliably and validly measure PROs. The PROMIS consists of a library of question banks that has been developed and operated by a network of National Institutes of Health-funded research sites and coordinating centers and covers many different health domains including pain, fatigue, anxiety, depression, social functioning, physical functioning, and sleep. PROMIS items are developed using Item Response Theory (IRT), wherein the answer to any individual item has a known mathematical probability of predicting the test taker’s overall measurement of the specific trait being tested. This is commonly administered using computer-adaptive testing (CAT), which presents to the test taker an initial item, scores the response to that item, and from the response then presents the most informative second item, and so forth until a predefined level of precision is reached. Because the items are individually validated, they can be used alone or in any combination, a feature that distinguishes the PROMIS from traditional fixed-length PRO instruments that require the completion of an instrument in its entirety to be valid.²⁷ In recent years, orthopedic research has been published with PROMIS physical function (PF) scores as primary outcome measures.^28-30 The PF item bank includes 124 items measuring upper extremity, lower extremity, central and instrumental activities of daily living. PF can be completed as a short form (SF) with a set number of questions or utilizing CAT and evaluates self-reported function and physical activity. An advantage is its ease of use and potential to minimize test burden with very few questions, often as little as 4 items, as compared to other traditional PROMs.³¹

Previously published work has demonstrated that, in patients undergoing meniscal surgery, the PROMIS PF CAT maintains construct validity and correlates well with currently used knee outcome instruments, including KOOS.²⁸ Work by the same group looking at the performance of the PROMIS PF CAT in patients indicated for ACL reconstruction shows that the PROMIS PF CAT correlates well with other PRO instruments for patients with ACL injuries, (SF-36 PF [r = 0.82, P < 0.01], KOOS Sport [r = 0.70, P < 0.01], KOOS ADL [r = 0.74, P < 0.01]), does not have floor or ceiling effects in this relatively young and healthy population, and has a low test burden.^32,33 Papuga and colleagues³³ also compared the International Knee Documentation Committee (IKDC) and PROMIS PF CAT on 106 subjects after ACL reconstruction and found good correlation.

Continue to: Quality of Life Outcome Measure...

QUALITY OF LIFE OUTCOME MEASURE FOR ACL DEFICIENCY (ACL-QOL)

The ACL-QOL Score was developed in 1998 as a disease-specific measure for patients with chronic ACL deficiency.³⁴ This scale consists of 32 separate items in 31 visual analog questions regarding symptoms and physical complaints, work-related concerns, recreational activities and sport participation or competition, lifestyle, and social and emotional health status relating to the knee. The raw score is transformed into a 0- to 100-point scale, with higher scores indicating a better outcome. The scale is valid, reliable, and responsive for patients with ACL insufficiency,^35,36 and is not applicable to other disorders of the knee. We recommend the ACL-QOL questionnaire be used in conjunction with other currently available objective and functional outcome measures.

CINCINNATI KNEE RATING SYSTEM

The Cincinnati Knee Rating System (CKRS) was first described in 1983 and was modified to include occupational activities, athletic activities, symptoms, and functional limitations.^37,38 There are 11 components, measuring symptoms and disability in sports activity, activities of daily living function, occupational rating, as well as sections that measure physical examination, laxity of the knee, and radiographic evidence of degenerative joint disease.³⁹ The measure is scored on a 100-point scale, with higher scores indicating better outcomes. Scores have been shown to be lower as compared with other outcome measures assessing the same clinical condition.^40,41 Barber-Westin and colleagues³⁹ confirmed the reliability, validity, and responsiveness of the CKRS by testing 350 subjects with and without knee ligament injuries. In 2001, Marx⁴² tested the CKRS subjective form for reliability, validity, and responsiveness and found it to be acceptable for clinical research.

LYSHOLM KNEE SCORE

The Lysholm Knee Score was published in 1982 and modified in 1985, consisting of an 8-question survey that evaluates outcomes after knee ligament surgery. Items include pain, instability, locking, squatting, limping, support usage, swelling, and stair-climbing ability, with pain and instability carrying the highest weight.⁴³ It is scored on a scale of 0 to 100, with high scores indicating higher functioning and fewer symptoms. It has been validated in patients with ACL injuries and meniscal injuries.⁴⁴ Although it is widely used to measure outcomes after ACL reconstruction,⁴⁵ it has received criticism in the evaluation of patients with other knee conditions.⁴⁶ The main advantage of the Lysholm Knee Score is its ability to note changes in activity in the same patient across different time periods (responsiveness). A limitation of the Lysholm Knee Score is that it does not measure the domains of functioning in daily activities, sports, and recreational activities. The Lysholm scoring system’s test-retest reliability and construct validity have been evaluated,^42,43,46 although there has been some concern regarding a ceiling effect and its validity, sensitivity, and reliability has been questioned.⁴⁷ Therefore, it is advised that this score be used in conjunction with other PRO scores.

INTERNATIONAL KNEE DOCUMENTATION COMMITTEE (IKDC) SUBJECTIVE KNEE FORM

In 1987, members of the European Society for Knee Surgery and Arthroscopy and the American Orthopaedic Society for Sports Medicine formed the IKDC to develop a standardized method for evaluating knee injuries and treatment. The IKDC Subjective Knee Evaluation Form was initially published in 1993, and in 2001 the form was revised by the American Orthopaedic Society for Sports Medicine to become a knee-specific assessment tool rather than a disease or condition-specific tool.⁴⁸ The IKDC subjective form is an 18-question, knee-specific survey designed to detect improvement or deterioration in symptoms, function, and ability to participate in sports activities experienced by patients following knee surgery or other interventions. The individual items are summed and transformed into a 0- to 100-point scale, with high scores representing higher levels of function and minimal symptoms. The IKDC is utilized to assess a variety of knee conditions including ligament, meniscus, articular cartilage, osteoarthritis, and patellofemoral pain.^48,49 Thus, this form can be used to assess any condition involving the knee and allow comparison between groups with different diagnoses. The IKDC has been validated for an ACL reconstruction population,⁴⁷ has been used to assess outcomes in recent clinical studies on ACL reconstruction,^50,51 and is one of the most frequently used measures for patients with ACL deficiency.³ The validity, responsiveness, and reliability of the IKDC subjective form has been confirmed for both adult and adolescent populations.^48,49,52-54

TEGNER ACTIVITY SCORES

The Tegner activity score was developed in 1985 and was designed to provide an objective value for a patient’s activity level.⁴⁴ This scale was developed to complement the Lysholm score. It consists of 1 sport-specific activity level question on a 0 to 10 scale that evaluates an individual’s ability to compete in a sporting activity. Scores between 1 and 5 represent work or recreational sports. Scores >5 represent higher-level recreational and competitive sports. The Tegner activity score is one of the most widely used activity scoring systems for patients with knee disorders,^55,56 commonly utilized with the Lysholm Knee Score.⁴⁴ One disadvantage of the Tegner activity score is that it relates to specific sports rather than functional activities, which limits its generalizability. We are not aware of any studies documenting the reliability or validity of this instrument.

Continue on: Marx Activity Rating Scale...

MARX ACTIVITY RATING SCALE

The Marx activity rating scale was developed to be utilized with other knee rating scales and outcome measures as an activity assessment.⁵⁷ In contrast to the Tegner activity score, the Marx activity rating scale measures function rather than sport-specific activity. The scale is a short, patient-based activity assessment that consists of a 4-question survey evaluating patients’ knee health by recording the frequency and intensity of participation in a sporting activity. Questions are scored from 0 to 4 on the basis of how often the activity is performed. The 4 sections of the Marx scale that are rated include running, cutting, decelerating, and pivoting. This scale has been validated in patients with ACL injuries, chondromalacia patellae, and meniscal lesions.^42,56-58 Acceptable ceiling effects of 3% and floor effects of 8% were noted in the study of ACL-injured patients.⁵⁷

AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS (AAOS) SPORTS KNEE SCALE

The American Academy of Orthopaedic Surgeons (AAOS) Sports Knee Rating Scale consists of 5 parts and 23 items, including a section addressing stiffness, swelling, pain and function (7 questions), locking/catching (4 questions), giving way (4 questions), limitations of activity (4 questions), and pain with activity (4 questions).^59,60 Items may be dropped if patients select particular responses, which can lead to difficulties when using the survey. This scoring system has been found to be satisfactory when all subscales were combined and the mean was calculated.⁴²

DISCUSSION

PRO measures play an increasingly important role in the measurement of success and impact of health care services. Specifically, for ACL reconstruction, patient satisfaction is key for demonstrating the value of operative or other interventions. Selecting a suitable outcome measurement tool can be daunting, as it can be difficult to ascertain which outcome measures are appropriate for the patient or disorder in question. As there is currently no instrument that is universally superior in the evaluation of ACL outcomes, clinicians must consider the specific patient population in which the outcome instrument has been evaluated. Investigators should also use instruments with reported minimal clinically important differences so that variation in scores can be interpreted as either clinically significant or not. When choosing which outcome instrument to use, there is rarely a single appropriate rating system that is entirely comprehensive. In most cases, a general health outcome measure should be used in combination with a condition-specific rating scale. Activity rating scales, such as Marx or Tegner, should be included, especially when evaluating patients with low-activity lifestyles.

CONCLUSION

There are a number of reliable, valid, and responsive outcome measures that can be utilized to evaluate outcomes following ACL reconstruction in an array of patient populations. Outcome measures should be relevant to patients, easy to use, reliable, valid, and responsive to change. By increasing familiarity with these outcome measures, orthopedic surgeons and investigators can develop better studies, interpret data, and implement findings in practice with sound and informed judgment. Future research should focus on identifying the most relevant outcome metrics for assessing function following ACL reconstruction.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Outcome instruments have become an essential part of the evaluation of functional recovery after anterior cruciate ligament (ACL) reconstruction. Although the clinical examination provides important objective information to assess graft integrity, stability, range of motion, and strength, these measurements do not take the patient’s perception into account. There are many knee outcome instruments, and it is challenging for surgeons to understand how to interpret clinical research and utilize these measures in a practical way. The purpose of this review is to provide an overview of the most commonly used outcome measures in patients undergoing ACL reconstruction and to examine and compare the psychometric performance (validity, reliability, responsiveness) of these measurement tools.

Anterior cruciate ligament (ACL) reconstruction is one of the most common elective orthopedic procedures.¹ Despite advances in surgical techniques, ACL reconstruction is associated with a lengthy recovery time, decreased performance, and increased rate of reinjury.² Patients undergoing ACL reconstruction are often active individuals who participate in demanding activities, and accurate assessment of their recovery helps to guide recovery counseling. In addition to objective clinical outcomes measured through physical examination, patient-reported outcome (PRO) instruments add the patient’s perspective, information critical in determining a successful outcome. A variety of outcome instruments have been used and validated for patients with ACL tears. It is important for orthopedic surgeons to know the advantages and disadvantages of each outcome tool in order to interpret clinical studies and assess postoperative patients.

Over the last 10 years, there has been an increase in the number of knee instruments and rating scales designed to measure PROs, with >54 scores designed for the ACL-deficient knee.³ No standardized instrument is currently universally accepted as superior following ACL reconstruction across the spectrum of patient populations. Clinicians and researchers must carefully consider an outcome instrument’s utility based on specific patient populations in which it has been evaluated. Appropriate selection of outcome measures is of fundamental importance for adequate demonstration of the efficacy and value of treatment interventions, especially in an era of healthcare reform with a focus on providing high-quality and cost-effective care.

The purpose of this review is to highlight current tools used to measure outcomes after ACL reconstruction. Current outcome measures vary widely in regards to their validity, reliability, minimal clinically important difference, and applicability to specific patient populations. We have thus identified the measures most commonly used today in studies and clinical follow-up after ACL reconstruction and their various advantages and limitations. This information may enhance the orthopedic surgeon’s understanding of what outcome measures may be utilized in clinical studies.

Continue to: Patient-Reported Outcome Instruments...

PATIENT-REPORTED OUTCOME INSTRUMENTS

Recently, there has been a transition to increased use of PRO instruments rather than clinician-based postoperative assessment, largely due to the increasing emphasis on patient satisfaction in determining the value of an orthopedic intervention.⁴ PRO instruments are widely used to capture the patient’s perception of general health, quality of life (QOL), daily function, and pain. PRO instruments offer the benefit of allowing patients to subjectively assess their knee function during daily living and sports activities, conveying to the provider the impact of ACL reconstruction on physical, psychological, and social aspects of everyday activities. Furthermore, patient satisfaction has been shown to closely follow outcome scores related to symptoms and function.⁵ A multitude of specific knee-related PRO instruments have been developed and validated to measure outcomes after ACL reconstruction for both research and clinical purposes (Table).

Table. ACL Outcome Measures

Abbreviations: AAOS, American Academy of Orthopaedic Surgeons; ACL, anterior cruciate ligament; ACL-QOL, anterior cruciate ligament quality of life score; CAT, computer-adapting testing; IKDC, International Knee Documentation Committee; KOOS, Knee Injury and Osteoarthritis Outcome Score; OA, osteoarthritis; PF, physical function; PROMIS, Patient-Reported Outcome Measurement Information System; Ref, references; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index.

MEASUREMENT PROPERTIES

In general, clinicians and investigators should use health-related outcome measures with established reliability, validity, patient relevance, and responsiveness for assessing the specific condition.⁶

Reliability refers to the degree to which a measurement score is free from random error, reflecting how consistent or reproducible the instrument is when administered under the same testing conditions. Internal consistency, test-retest reliability, and measurement error are measures of reliability. Internal consistency is tested after a single administration and assesses how well items within a scale measure a single underlying dimension, represented using item-total correlation coefficients and Cronbach’s alpha. A Cronbach’s alpha of 0.70 to 0.95 is generally defined as good.⁷ Test-retest reliability is designed to appraise variation over time in stable patients and is represented using the intraclass correlation coefficient (ICC).⁸ An ICC >0.7 is considered acceptable; >0.8, good; and >0.9, excellent.⁹ An aspect of accuracy is whether the scoring system measures the full range of the disease or complaints. The incidence of minimum (floor) and maximum (ceiling) scores can be calculated for outcome scores. An instrument with low floor and ceiling effects, below 10% to 15%, is more inconclusive and can be more reliably used to measure patients at the high and low end of the scoring system.¹⁰

Validity is the ability of an outcome instrument to measure what it is intended to measure. Establishing validity is complex and requires evaluation of several facets, including content validity, construct validity, and criterion validity. Content validity is a relatively subjective judgment explaining the ability of an instrument to assess the critical features of the problem. Construct validity evaluates whether the questionnaire measures what it intends to measure, and is often assessed by correlating scores form one instrument to those from other proven instruments that are already accepted as valid. Finally, criterion validity assesses the correlation between the score and a previously established “gold standard” instrument.

Responsiveness is the ability of the instrument to detect a change or identify improvement or worsening of a clinical condition over time. Most frequently, the effect size (observed change/standard deviation of baseline scores) and standardized response mean (observed change/standard deviation of change) are used as measures of responsiveness. The minimal clinically important difference of an outcome measure is the smallest change in an outcome score that corresponds to a change in patient condition.

Continue to: ACL Outcome Instruments...

ACL OUTCOME INSTRUMENTS

WESTERN ONTARIO AND MCMASTER UNIVERSITIES OSTEOARTHRITIS INDEX (WOMAC LK 3.0)

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC LK 3.0) was developed in 1982 and is a widely used, disease-specific instrument recommended for the evaluation of treatment effects in patients with hip and knee osteoarthritis.¹¹ Available in more than 80 languages, it is a self-administered, generic health status questionnaire developed to assess pain, function, and stiffness in daily living, taking respondents between 3 to 7.5 minutes for completion.¹² Using visual analog scales, the 24 items probe the 3 subscales: pain (5 items), stiffness (2 items), and functional difficulty (17 items). Scores are calculated for each dimension, and the total score is normalized to a 100-point scale, with 0 indicating severe symptoms and 100 indicating no symptoms and higher function. The WOMAC score can also be calculated from the Knee Injury and Osteoarthritis Outcome Score (KOOS). The WOMAC questionnaire is well recognized for its good validity, reliability, and responsiveness, and is the most commonly used outcome measure for osteoarthritis.^13-15 Considering its focus on older patients with osteoarthritis, it may not be appropriate for use in a young and active population.

KNEE INJURY AND OSTEOARTHRITIS OUTCOME SCORE (KOOS)

The KOOS is a knee-specific questionnaire developed as an extension of the WOMAC to evaluate the functional status and QOL of patients with any type of knee injury who are at an increased risk of developing osteoarthritis.¹⁶ The patient-based questionnaire is available in over 30 languages and covers both the short- and long-term consequences of an injury of the knee causing traumatic damage to cartilage, ligaments, and menisci. The KOOS is 42 items graded on a 5-point Likert scale, covering 5 subscales: pain (9 items), symptoms (7 items), function in activities of daily living (17 items), function in sports/recreation (5 items), and knee-related QOL (4 items). The questionnaire is self-administered and takes about 10 minutes to complete. Scores are calculated for each dimension, and the total score is transformed to a 0 to 100 scale, with 0 representing severe knee problems and 100 representing no knee problems and better outcome. An advantage of the KOOS is that it evaluates both knee injuries and osteoarthritis; therefore, it is arguably more suitable for evaluating patients over the long-term. The KOOS has been validated for several orthopedic interventions, including ACL reconstruction and rehabilitation^16,17 as well as meniscectomy¹⁸ and total knee replacement.¹⁹ Population-based reference data for the adult population according to age and gender have also been established.²⁰ The KOOS is increasingly utilized in clinical studies on ACL reconstruction.^21-25 The questions of the WOMAC were retained so that a WOMAC score might be calculated separately and compared with the KOOS score.²⁶

PATIENT-REPORTED OUTCOMES INFORMATION SYSTEM (PROMIS)

Since 2004, The National Institutes of Health (NIH) has funded the development of the Patient-Reported Outcome Measurement Information System (PROMIS), a set of flexible tools that reliably and validly measure PROs. The PROMIS consists of a library of question banks that has been developed and operated by a network of National Institutes of Health-funded research sites and coordinating centers and covers many different health domains including pain, fatigue, anxiety, depression, social functioning, physical functioning, and sleep. PROMIS items are developed using Item Response Theory (IRT), wherein the answer to any individual item has a known mathematical probability of predicting the test taker’s overall measurement of the specific trait being tested. This is commonly administered using computer-adaptive testing (CAT), which presents to the test taker an initial item, scores the response to that item, and from the response then presents the most informative second item, and so forth until a predefined level of precision is reached. Because the items are individually validated, they can be used alone or in any combination, a feature that distinguishes the PROMIS from traditional fixed-length PRO instruments that require the completion of an instrument in its entirety to be valid.²⁷ In recent years, orthopedic research has been published with PROMIS physical function (PF) scores as primary outcome measures.^28-30 The PF item bank includes 124 items measuring upper extremity, lower extremity, central and instrumental activities of daily living. PF can be completed as a short form (SF) with a set number of questions or utilizing CAT and evaluates self-reported function and physical activity. An advantage is its ease of use and potential to minimize test burden with very few questions, often as little as 4 items, as compared to other traditional PROMs.³¹

Previously published work has demonstrated that, in patients undergoing meniscal surgery, the PROMIS PF CAT maintains construct validity and correlates well with currently used knee outcome instruments, including KOOS.²⁸ Work by the same group looking at the performance of the PROMIS PF CAT in patients indicated for ACL reconstruction shows that the PROMIS PF CAT correlates well with other PRO instruments for patients with ACL injuries, (SF-36 PF [r = 0.82, P < 0.01], KOOS Sport [r = 0.70, P < 0.01], KOOS ADL [r = 0.74, P < 0.01]), does not have floor or ceiling effects in this relatively young and healthy population, and has a low test burden.^32,33 Papuga and colleagues³³ also compared the International Knee Documentation Committee (IKDC) and PROMIS PF CAT on 106 subjects after ACL reconstruction and found good correlation.

Continue to: Quality of Life Outcome Measure...

QUALITY OF LIFE OUTCOME MEASURE FOR ACL DEFICIENCY (ACL-QOL)

The ACL-QOL Score was developed in 1998 as a disease-specific measure for patients with chronic ACL deficiency.³⁴ This scale consists of 32 separate items in 31 visual analog questions regarding symptoms and physical complaints, work-related concerns, recreational activities and sport participation or competition, lifestyle, and social and emotional health status relating to the knee. The raw score is transformed into a 0- to 100-point scale, with higher scores indicating a better outcome. The scale is valid, reliable, and responsive for patients with ACL insufficiency,^35,36 and is not applicable to other disorders of the knee. We recommend the ACL-QOL questionnaire be used in conjunction with other currently available objective and functional outcome measures.

CINCINNATI KNEE RATING SYSTEM

The Cincinnati Knee Rating System (CKRS) was first described in 1983 and was modified to include occupational activities, athletic activities, symptoms, and functional limitations.^37,38 There are 11 components, measuring symptoms and disability in sports activity, activities of daily living function, occupational rating, as well as sections that measure physical examination, laxity of the knee, and radiographic evidence of degenerative joint disease.³⁹ The measure is scored on a 100-point scale, with higher scores indicating better outcomes. Scores have been shown to be lower as compared with other outcome measures assessing the same clinical condition.^40,41 Barber-Westin and colleagues³⁹ confirmed the reliability, validity, and responsiveness of the CKRS by testing 350 subjects with and without knee ligament injuries. In 2001, Marx⁴² tested the CKRS subjective form for reliability, validity, and responsiveness and found it to be acceptable for clinical research.

LYSHOLM KNEE SCORE

The Lysholm Knee Score was published in 1982 and modified in 1985, consisting of an 8-question survey that evaluates outcomes after knee ligament surgery. Items include pain, instability, locking, squatting, limping, support usage, swelling, and stair-climbing ability, with pain and instability carrying the highest weight.⁴³ It is scored on a scale of 0 to 100, with high scores indicating higher functioning and fewer symptoms. It has been validated in patients with ACL injuries and meniscal injuries.⁴⁴ Although it is widely used to measure outcomes after ACL reconstruction,⁴⁵ it has received criticism in the evaluation of patients with other knee conditions.⁴⁶ The main advantage of the Lysholm Knee Score is its ability to note changes in activity in the same patient across different time periods (responsiveness). A limitation of the Lysholm Knee Score is that it does not measure the domains of functioning in daily activities, sports, and recreational activities. The Lysholm scoring system’s test-retest reliability and construct validity have been evaluated,^42,43,46 although there has been some concern regarding a ceiling effect and its validity, sensitivity, and reliability has been questioned.⁴⁷ Therefore, it is advised that this score be used in conjunction with other PRO scores.

INTERNATIONAL KNEE DOCUMENTATION COMMITTEE (IKDC) SUBJECTIVE KNEE FORM

In 1987, members of the European Society for Knee Surgery and Arthroscopy and the American Orthopaedic Society for Sports Medicine formed the IKDC to develop a standardized method for evaluating knee injuries and treatment. The IKDC Subjective Knee Evaluation Form was initially published in 1993, and in 2001 the form was revised by the American Orthopaedic Society for Sports Medicine to become a knee-specific assessment tool rather than a disease or condition-specific tool.⁴⁸ The IKDC subjective form is an 18-question, knee-specific survey designed to detect improvement or deterioration in symptoms, function, and ability to participate in sports activities experienced by patients following knee surgery or other interventions. The individual items are summed and transformed into a 0- to 100-point scale, with high scores representing higher levels of function and minimal symptoms. The IKDC is utilized to assess a variety of knee conditions including ligament, meniscus, articular cartilage, osteoarthritis, and patellofemoral pain.^48,49 Thus, this form can be used to assess any condition involving the knee and allow comparison between groups with different diagnoses. The IKDC has been validated for an ACL reconstruction population,⁴⁷ has been used to assess outcomes in recent clinical studies on ACL reconstruction,^50,51 and is one of the most frequently used measures for patients with ACL deficiency.³ The validity, responsiveness, and reliability of the IKDC subjective form has been confirmed for both adult and adolescent populations.^48,49,52-54

TEGNER ACTIVITY SCORES

The Tegner activity score was developed in 1985 and was designed to provide an objective value for a patient’s activity level.⁴⁴ This scale was developed to complement the Lysholm score. It consists of 1 sport-specific activity level question on a 0 to 10 scale that evaluates an individual’s ability to compete in a sporting activity. Scores between 1 and 5 represent work or recreational sports. Scores >5 represent higher-level recreational and competitive sports. The Tegner activity score is one of the most widely used activity scoring systems for patients with knee disorders,^55,56 commonly utilized with the Lysholm Knee Score.⁴⁴ One disadvantage of the Tegner activity score is that it relates to specific sports rather than functional activities, which limits its generalizability. We are not aware of any studies documenting the reliability or validity of this instrument.

Continue on: Marx Activity Rating Scale...

MARX ACTIVITY RATING SCALE

The Marx activity rating scale was developed to be utilized with other knee rating scales and outcome measures as an activity assessment.⁵⁷ In contrast to the Tegner activity score, the Marx activity rating scale measures function rather than sport-specific activity. The scale is a short, patient-based activity assessment that consists of a 4-question survey evaluating patients’ knee health by recording the frequency and intensity of participation in a sporting activity. Questions are scored from 0 to 4 on the basis of how often the activity is performed. The 4 sections of the Marx scale that are rated include running, cutting, decelerating, and pivoting. This scale has been validated in patients with ACL injuries, chondromalacia patellae, and meniscal lesions.^42,56-58 Acceptable ceiling effects of 3% and floor effects of 8% were noted in the study of ACL-injured patients.⁵⁷

AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS (AAOS) SPORTS KNEE SCALE

The American Academy of Orthopaedic Surgeons (AAOS) Sports Knee Rating Scale consists of 5 parts and 23 items, including a section addressing stiffness, swelling, pain and function (7 questions), locking/catching (4 questions), giving way (4 questions), limitations of activity (4 questions), and pain with activity (4 questions).^59,60 Items may be dropped if patients select particular responses, which can lead to difficulties when using the survey. This scoring system has been found to be satisfactory when all subscales were combined and the mean was calculated.⁴²

DISCUSSION

PRO measures play an increasingly important role in the measurement of success and impact of health care services. Specifically, for ACL reconstruction, patient satisfaction is key for demonstrating the value of operative or other interventions. Selecting a suitable outcome measurement tool can be daunting, as it can be difficult to ascertain which outcome measures are appropriate for the patient or disorder in question. As there is currently no instrument that is universally superior in the evaluation of ACL outcomes, clinicians must consider the specific patient population in which the outcome instrument has been evaluated. Investigators should also use instruments with reported minimal clinically important differences so that variation in scores can be interpreted as either clinically significant or not. When choosing which outcome instrument to use, there is rarely a single appropriate rating system that is entirely comprehensive. In most cases, a general health outcome measure should be used in combination with a condition-specific rating scale. Activity rating scales, such as Marx or Tegner, should be included, especially when evaluating patients with low-activity lifestyles.

CONCLUSION

There are a number of reliable, valid, and responsive outcome measures that can be utilized to evaluate outcomes following ACL reconstruction in an array of patient populations. Outcome measures should be relevant to patients, easy to use, reliable, valid, and responsive to change. By increasing familiarity with these outcome measures, orthopedic surgeons and investigators can develop better studies, interpret data, and implement findings in practice with sound and informed judgment. Future research should focus on identifying the most relevant outcome metrics for assessing function following ACL reconstruction.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Blunt trauma to the anterior knee typically results in a contusion or fracture of the patella. Additionally, injury to the extensor mechanism may come from a partial or full disruption of the patellar or quadriceps tendon. A professional baseball player suffered an injury to his knee after he collided with an outfield wall. Acute swelling in the suprapatellar soft tissues concealed a palpable defect, which initially was suspected to be an injury to the quadriceps tendon. Magnetic resonance imaging of the knee revealed an intact extensor mechanism; moreover, a fracture of the subcutaneous fat anterior to the quadriceps tendon was evident and diagnosed as a fat fracture.

Fat fracture is a rare diagnosis, and to the best of our knowledge, this is the first reported diagnosis in a professional athlete. Conservative management including, but not limited to, range of motion exercises, hydrotherapy, and iontophoresis effectively treated the athlete’s injury.

Blunt trauma to the anterior knee can result in a contusion or fracture of the patella, subluxation of the patella, and injury to the quadriceps or patellar tendon. Typically, a contusion or non-displaced fracture of the patella clinically presents with a direct anterior effusion and point tenderness. A displaced fracture or tendon deficit typically has an extensor lag or weakness in extension. Fat fracture or traumatic lipomata has been previously described in 1 case of anterior knee pain after blunt injury.¹

In this article, we present the case of a 32-year-old professional baseball player who suffered a blunt injury to his left knee after collision with the outfield wall and experienced both anterior and medial knee pain. The patient provided written informed consent for print and electronic publication of this case report.

CASE

A 32-year-old outfielder for a professional baseball team was attempting a catch in the outfield when his left knee collided with the padded outfield wall in a semiflexed position. The player was able to walk off the field in the middle of the inning; however, he then experienced increasing pain and was unable to return to play. He had no prior history of significant knee pain or injury. He complained only of pain, with no instability or sensation of catching or locking.

Continue to: Physical examination of the patient...

Mild coronal laxity of the patella was noted compared with that of the contralateral knee. Hip range of motion (ROM) was intact, but knee ROM was limited to 110° of flexion, with the complaint of anterior tightness at this position. He was able to fully extend his knee without symptoms. The knee was stable to varus and valgus stress at both 0° and 30° of flexion. Lachman and anterior and posterior drawer tests were negative and symmetric to the contralateral knee. The McMurray test for meniscal pathology also was negative. Radiographs of the left knee were completed and were negative for fracture.

OUTCOMES

The initial clinical diagnosis was a patellar contusion and sprain of the medial retinaculum, and the athlete was treated with multiple modalities available in the athletic training room. Rehabilitation included activity modifications, passive and active ROM activities, quadriceps isometric exercises, and neuromuscular control activities. Adjunctive modalities included cryotherapy, hydrotherapy, topical hematoma cream, and iontophoresis.² This aggressive treatment was continued for 3 days with decreased but persistent pain with running drills and limited knee flexion. Repeat clinical examination revealed a decreased swelling, but there was evidence of a clinically palpable defect anteriorly proximal to the patella. Although the patient could perform a straight leg raise, a partial injury to the quadriceps became plausible. Magnetic resonance imaging (MRI) of the left knee was performed, owing to the persistent pain and limited flexion despite aggressive conservative management, as well as the palpable soft-tissue defect.

MRI was performed using a 3T (Tesla) system (GE Healthcare) with a GE Healthcare Precision 8-channel knee coil. Routine knee protocol imaging was performed to include the distal quadriceps tendon due to clinical concern for a quadriceps tear. Sagittal proton density and proton-density fat-saturated (PD FS), coronal T1 and PD FS, and axial T1 and PD FS sequences were acquired.

An acutely marginated, 1.5 cm × 3 cm, longitudinal and transverse fluid defect “crevasse” was identified at the midline in the prepatellar subcutaneous fat overlying the distal quadriceps tendon and corresponded to a clinically palpable abnormality (Figures 1, 2). 

Continue to: These findings explained...

DISCUSSION

A fat fracture was first described in 1972 in 12 cases of buttock fat fractures after blunt trauma.³ The authors explained that fat lobules are typically arranged in layers and supported by horizontal and vertical fibrous septa. Typical loads flatten the lobules and disperse the forces throughout the layer. However, abnormal loads to a local area disrupt the fat lobules and shear the septa, resulting in decreased integrity of the interface between the epidermis and the fascia.

However, the extremities typically have less adipose tissue than in the buttocks, and the anterior knee is prone to blunt trauma. A previous description of a fat fracture in the knee noted a palpable defect in the quadriceps tendon and an inability to perform a straight leg raise. Our case initially presented with swelling, which concealed any soft-tissue defect. Furthermore, a straight leg raise was always intact despite the fat fracture defect surfacing after anterior swelling subsided. However, the disparity in these 2 cases highlights the spectrum of injury that is possible, as well as the difficulty in diagnosing a fat fracture. The previous report used ultrasound to confirm the diagnosis and assess the integrity of adjacent musculotendinous structures. An ultrasound may be readily available in athletic training rooms.¹ Of note, to the best of our knowledge, this is the first case in the literature to report a fat fracture in a professional athlete and in baseball players. Furthermore, this case report describes an athlete who presented with anterior and medial knee pain. The edema from the fat fracture dispersed into the medial prepatellar bursa, which could be confused with edema from an injury to the medial-sided soft tissues.

Although these injuries do not require operative management, conservative measures may not be as effective as those in a patellar contusion or ligamentous sprain, and prolonged treatment may be necessary. Additionally, healthcare providers should be aware of this possible source of injury and counsel on an appropriate recovery time. Ideally, further recognition of such injuries can facilitate improved management and a faster return to activity.

ABSTRACT

Blunt trauma to the anterior knee typically results in a contusion or fracture of the patella. Additionally, injury to the extensor mechanism may come from a partial or full disruption of the patellar or quadriceps tendon. A professional baseball player suffered an injury to his knee after he collided with an outfield wall. Acute swelling in the suprapatellar soft tissues concealed a palpable defect, which initially was suspected to be an injury to the quadriceps tendon. Magnetic resonance imaging of the knee revealed an intact extensor mechanism; moreover, a fracture of the subcutaneous fat anterior to the quadriceps tendon was evident and diagnosed as a fat fracture.

Fat fracture is a rare diagnosis, and to the best of our knowledge, this is the first reported diagnosis in a professional athlete. Conservative management including, but not limited to, range of motion exercises, hydrotherapy, and iontophoresis effectively treated the athlete’s injury.

Blunt trauma to the anterior knee can result in a contusion or fracture of the patella, subluxation of the patella, and injury to the quadriceps or patellar tendon. Typically, a contusion or non-displaced fracture of the patella clinically presents with a direct anterior effusion and point tenderness. A displaced fracture or tendon deficit typically has an extensor lag or weakness in extension. Fat fracture or traumatic lipomata has been previously described in 1 case of anterior knee pain after blunt injury.¹

In this article, we present the case of a 32-year-old professional baseball player who suffered a blunt injury to his left knee after collision with the outfield wall and experienced both anterior and medial knee pain. The patient provided written informed consent for print and electronic publication of this case report.

CASE

A 32-year-old outfielder for a professional baseball team was attempting a catch in the outfield when his left knee collided with the padded outfield wall in a semiflexed position. The player was able to walk off the field in the middle of the inning; however, he then experienced increasing pain and was unable to return to play. He had no prior history of significant knee pain or injury. He complained only of pain, with no instability or sensation of catching or locking.

Continue to: Physical examination of the patient...

Mild coronal laxity of the patella was noted compared with that of the contralateral knee. Hip range of motion (ROM) was intact, but knee ROM was limited to 110° of flexion, with the complaint of anterior tightness at this position. He was able to fully extend his knee without symptoms. The knee was stable to varus and valgus stress at both 0° and 30° of flexion. Lachman and anterior and posterior drawer tests were negative and symmetric to the contralateral knee. The McMurray test for meniscal pathology also was negative. Radiographs of the left knee were completed and were negative for fracture.

OUTCOMES

The initial clinical diagnosis was a patellar contusion and sprain of the medial retinaculum, and the athlete was treated with multiple modalities available in the athletic training room. Rehabilitation included activity modifications, passive and active ROM activities, quadriceps isometric exercises, and neuromuscular control activities. Adjunctive modalities included cryotherapy, hydrotherapy, topical hematoma cream, and iontophoresis.² This aggressive treatment was continued for 3 days with decreased but persistent pain with running drills and limited knee flexion. Repeat clinical examination revealed a decreased swelling, but there was evidence of a clinically palpable defect anteriorly proximal to the patella. Although the patient could perform a straight leg raise, a partial injury to the quadriceps became plausible. Magnetic resonance imaging (MRI) of the left knee was performed, owing to the persistent pain and limited flexion despite aggressive conservative management, as well as the palpable soft-tissue defect.

MRI was performed using a 3T (Tesla) system (GE Healthcare) with a GE Healthcare Precision 8-channel knee coil. Routine knee protocol imaging was performed to include the distal quadriceps tendon due to clinical concern for a quadriceps tear. Sagittal proton density and proton-density fat-saturated (PD FS), coronal T1 and PD FS, and axial T1 and PD FS sequences were acquired.

An acutely marginated, 1.5 cm × 3 cm, longitudinal and transverse fluid defect “crevasse” was identified at the midline in the prepatellar subcutaneous fat overlying the distal quadriceps tendon and corresponded to a clinically palpable abnormality (Figures 1, 2). 

Continue to: These findings explained...

DISCUSSION

A fat fracture was first described in 1972 in 12 cases of buttock fat fractures after blunt trauma.³ The authors explained that fat lobules are typically arranged in layers and supported by horizontal and vertical fibrous septa. Typical loads flatten the lobules and disperse the forces throughout the layer. However, abnormal loads to a local area disrupt the fat lobules and shear the septa, resulting in decreased integrity of the interface between the epidermis and the fascia.

However, the extremities typically have less adipose tissue than in the buttocks, and the anterior knee is prone to blunt trauma. A previous description of a fat fracture in the knee noted a palpable defect in the quadriceps tendon and an inability to perform a straight leg raise. Our case initially presented with swelling, which concealed any soft-tissue defect. Furthermore, a straight leg raise was always intact despite the fat fracture defect surfacing after anterior swelling subsided. However, the disparity in these 2 cases highlights the spectrum of injury that is possible, as well as the difficulty in diagnosing a fat fracture. The previous report used ultrasound to confirm the diagnosis and assess the integrity of adjacent musculotendinous structures. An ultrasound may be readily available in athletic training rooms.¹ Of note, to the best of our knowledge, this is the first case in the literature to report a fat fracture in a professional athlete and in baseball players. Furthermore, this case report describes an athlete who presented with anterior and medial knee pain. The edema from the fat fracture dispersed into the medial prepatellar bursa, which could be confused with edema from an injury to the medial-sided soft tissues.

Although these injuries do not require operative management, conservative measures may not be as effective as those in a patellar contusion or ligamentous sprain, and prolonged treatment may be necessary. Additionally, healthcare providers should be aware of this possible source of injury and counsel on an appropriate recovery time. Ideally, further recognition of such injuries can facilitate improved management and a faster return to activity.

ABSTRACT

Blunt trauma to the anterior knee typically results in a contusion or fracture of the patella. Additionally, injury to the extensor mechanism may come from a partial or full disruption of the patellar or quadriceps tendon. A professional baseball player suffered an injury to his knee after he collided with an outfield wall. Acute swelling in the suprapatellar soft tissues concealed a palpable defect, which initially was suspected to be an injury to the quadriceps tendon. Magnetic resonance imaging of the knee revealed an intact extensor mechanism; moreover, a fracture of the subcutaneous fat anterior to the quadriceps tendon was evident and diagnosed as a fat fracture.

Fat fracture is a rare diagnosis, and to the best of our knowledge, this is the first reported diagnosis in a professional athlete. Conservative management including, but not limited to, range of motion exercises, hydrotherapy, and iontophoresis effectively treated the athlete’s injury.

Blunt trauma to the anterior knee can result in a contusion or fracture of the patella, subluxation of the patella, and injury to the quadriceps or patellar tendon. Typically, a contusion or non-displaced fracture of the patella clinically presents with a direct anterior effusion and point tenderness. A displaced fracture or tendon deficit typically has an extensor lag or weakness in extension. Fat fracture or traumatic lipomata has been previously described in 1 case of anterior knee pain after blunt injury.¹

In this article, we present the case of a 32-year-old professional baseball player who suffered a blunt injury to his left knee after collision with the outfield wall and experienced both anterior and medial knee pain. The patient provided written informed consent for print and electronic publication of this case report.

CASE

A 32-year-old outfielder for a professional baseball team was attempting a catch in the outfield when his left knee collided with the padded outfield wall in a semiflexed position. The player was able to walk off the field in the middle of the inning; however, he then experienced increasing pain and was unable to return to play. He had no prior history of significant knee pain or injury. He complained only of pain, with no instability or sensation of catching or locking.

Continue to: Physical examination of the patient...

Mild coronal laxity of the patella was noted compared with that of the contralateral knee. Hip range of motion (ROM) was intact, but knee ROM was limited to 110° of flexion, with the complaint of anterior tightness at this position. He was able to fully extend his knee without symptoms. The knee was stable to varus and valgus stress at both 0° and 30° of flexion. Lachman and anterior and posterior drawer tests were negative and symmetric to the contralateral knee. The McMurray test for meniscal pathology also was negative. Radiographs of the left knee were completed and were negative for fracture.

OUTCOMES

The initial clinical diagnosis was a patellar contusion and sprain of the medial retinaculum, and the athlete was treated with multiple modalities available in the athletic training room. Rehabilitation included activity modifications, passive and active ROM activities, quadriceps isometric exercises, and neuromuscular control activities. Adjunctive modalities included cryotherapy, hydrotherapy, topical hematoma cream, and iontophoresis.² This aggressive treatment was continued for 3 days with decreased but persistent pain with running drills and limited knee flexion. Repeat clinical examination revealed a decreased swelling, but there was evidence of a clinically palpable defect anteriorly proximal to the patella. Although the patient could perform a straight leg raise, a partial injury to the quadriceps became plausible. Magnetic resonance imaging (MRI) of the left knee was performed, owing to the persistent pain and limited flexion despite aggressive conservative management, as well as the palpable soft-tissue defect.

MRI was performed using a 3T (Tesla) system (GE Healthcare) with a GE Healthcare Precision 8-channel knee coil. Routine knee protocol imaging was performed to include the distal quadriceps tendon due to clinical concern for a quadriceps tear. Sagittal proton density and proton-density fat-saturated (PD FS), coronal T1 and PD FS, and axial T1 and PD FS sequences were acquired.

An acutely marginated, 1.5 cm × 3 cm, longitudinal and transverse fluid defect “crevasse” was identified at the midline in the prepatellar subcutaneous fat overlying the distal quadriceps tendon and corresponded to a clinically palpable abnormality (Figures 1, 2). 

Continue to: These findings explained...

DISCUSSION

A fat fracture was first described in 1972 in 12 cases of buttock fat fractures after blunt trauma.³ The authors explained that fat lobules are typically arranged in layers and supported by horizontal and vertical fibrous septa. Typical loads flatten the lobules and disperse the forces throughout the layer. However, abnormal loads to a local area disrupt the fat lobules and shear the septa, resulting in decreased integrity of the interface between the epidermis and the fascia.

However, the extremities typically have less adipose tissue than in the buttocks, and the anterior knee is prone to blunt trauma. A previous description of a fat fracture in the knee noted a palpable defect in the quadriceps tendon and an inability to perform a straight leg raise. Our case initially presented with swelling, which concealed any soft-tissue defect. Furthermore, a straight leg raise was always intact despite the fat fracture defect surfacing after anterior swelling subsided. However, the disparity in these 2 cases highlights the spectrum of injury that is possible, as well as the difficulty in diagnosing a fat fracture. The previous report used ultrasound to confirm the diagnosis and assess the integrity of adjacent musculotendinous structures. An ultrasound may be readily available in athletic training rooms.¹ Of note, to the best of our knowledge, this is the first case in the literature to report a fat fracture in a professional athlete and in baseball players. Furthermore, this case report describes an athlete who presented with anterior and medial knee pain. The edema from the fat fracture dispersed into the medial prepatellar bursa, which could be confused with edema from an injury to the medial-sided soft tissues.

Although these injuries do not require operative management, conservative measures may not be as effective as those in a patellar contusion or ligamentous sprain, and prolonged treatment may be necessary. Additionally, healthcare providers should be aware of this possible source of injury and counsel on an appropriate recovery time. Ideally, further recognition of such injuries can facilitate improved management and a faster return to activity.