Case Reports

Changes in the appearance of the nail apparatus can be produced by a variety of conditions. Onychomatricoma is an unusual benign tumor with specific clinical characteristics that was first described more than 2 decades ago.¹ It is often and easily misdiagnosed because the condition rarely has been described. We report a case of onychomatricoma in a 54-year-old Colombian man who presented with a deformity of the nail plate on the right index finger that corresponded with the classic description of onychomatricoma. We emphasize the importance of reporting such lesions to prevent misdiagnosis and delay of proper treatment.

Case Report

A 54-year-old Colombian man presented with nail dystrophy involving the right index finger of 2 years’ duration. He did not recall any trauma prior to the onset of the nail abnormalities. Several topical treatments had previously been ineffective. Physical examination revealed a longitudinally banded thickening of the lateral half of the nail plate on the right index finger with yellowish brown discoloration, transverse overcurvature of the nail, longitudinal white lines, and splinter hemorrhages (Figure 1). Direct microscopy and fungal culture were performed to diagnose or rule out onychomycosis.

Figure 1. Clinically dystrophic nail with transverse overcurvature, thickening, yellow discoloration of the nail plate, longitudinal bands, and splinter hemorrhages on the right index finger.

A clinical diagnosis of onychomatricoma was made, and the lesion was surgically removed and sent for histopathologic study (Figure 2). The radial half of the nail plate was avulsed, and the proximal part of the removed nail plate contained a large, firmly attached, filamentous tumor arising from the nail matrix (Figure 3) with multiple fine filiform projections (Figure 4). The nail bed was cleaned with a curette to remove any debris, the ulnar half of the nail plate and nail bed was left in place, and the radial border was reconstructed. Histology confirmed the clinical diagnosis (Figure 5). No recurrences of the tumor were seen 36 months following surgery.

Figure 2. Macroscopic appearance of the removed nail plate and tumor.

Figure 3. Reflection of the proximal nail fold revealed projections arising from the nail matrix.

Figure 4. When bisected, the nail plate exhibited multiple channels formed by fine filiform projections.

Comment

Since the original report of this tumor,¹ fewer than 10 cases of onychomatricoma have been reported in Latin America,^2-5 with no more than 80 cases reported worldwide.⁶ Clinicians and academicians are becoming interested in the topic, which will result in better recognition and more reports in the literature.

The clinical differential diagnosis of onycho-matricoma is extensive,^7,8 but onychomatricoma has characteristic clinical and histopathologic features that allow its separation from other nail disorders and subungual tumors (Table).⁹ There are 4 cardinal clinical signs that suggest a diagnosis of onychomatricoma: (1) banded or diffuse thickening of the nail plate of variable widths; (2) yellowish discoloration of the involved nail plate, often showing fine splinter hemorrhages in the proximal nail portion; (3) transverse overcurvature of the nail; and (4) exposure of a filamentous tufted tumor emerging from the matrix in a funnel-shaped nail by avulsion.¹

Figure 5. Histology revealed multiple filiform projections of dense connective tissue alternating with vertically oriented invaginations covered by nail matrix epithelium (A)(H&E, original magnification ×2.5). Papillomatous cellular fibrous tissue underlying nail matrix epithelium was noted (B)(H&E, original magnification ×10).

Histologic findings of onychomatricoma typically demonstrate a fibroepithelial tumor with a biphasic growth pattern mimicking normal nail matrix histology, including a proximal zone, which corresponds to the base of the fibroepithelial tumor, and a distal zone, which is composed of multiple epithelial digitations that extend into the small cavities present in the attached nail.^10-12 Nevertheless, the anatomic tumor location, the often fragmented aspect of the tissue specimen, and the choice of the section planes may change the typical histologic features seen in onychomatricoma.¹³ Stromal prominence, cellularity, and atypia may vary in individual cases.^10-12

The etiology of onychomatricoma is not yet known. Although it has been suggested that onychomatricoma could be an epithelial and connective tissue hamartoma simulating the nail matrix structure,^1,10 the more recent concept of an epithelial onychogenic tumor with onychogenic mesenchyme will help to clarify its etiology because new histopathologic and immunohistochemical features suggest a neoplastic nature.¹⁴ On the other hand, predisposing factors such as trauma to the nail plate and onychomycosis may play a role,⁷ as the thumbs, index fingers, and great toes are more susceptible to onychomycosis and accidental trauma.

Conclusion

Our patient fulfilled the criteria of onychomatricoma.¹ Onychomatricoma should be kept in mind in the differential diagnosis of subungual or  periungual tumors to avoid misdiagnosis and erroneous treatments.

Changes in the appearance of the nail apparatus can be produced by a variety of conditions. Onychomatricoma is an unusual benign tumor with specific clinical characteristics that was first described more than 2 decades ago.¹ It is often and easily misdiagnosed because the condition rarely has been described. We report a case of onychomatricoma in a 54-year-old Colombian man who presented with a deformity of the nail plate on the right index finger that corresponded with the classic description of onychomatricoma. We emphasize the importance of reporting such lesions to prevent misdiagnosis and delay of proper treatment.

Case Report

A 54-year-old Colombian man presented with nail dystrophy involving the right index finger of 2 years’ duration. He did not recall any trauma prior to the onset of the nail abnormalities. Several topical treatments had previously been ineffective. Physical examination revealed a longitudinally banded thickening of the lateral half of the nail plate on the right index finger with yellowish brown discoloration, transverse overcurvature of the nail, longitudinal white lines, and splinter hemorrhages (Figure 1). Direct microscopy and fungal culture were performed to diagnose or rule out onychomycosis.

Figure 1. Clinically dystrophic nail with transverse overcurvature, thickening, yellow discoloration of the nail plate, longitudinal bands, and splinter hemorrhages on the right index finger.

A clinical diagnosis of onychomatricoma was made, and the lesion was surgically removed and sent for histopathologic study (Figure 2). The radial half of the nail plate was avulsed, and the proximal part of the removed nail plate contained a large, firmly attached, filamentous tumor arising from the nail matrix (Figure 3) with multiple fine filiform projections (Figure 4). The nail bed was cleaned with a curette to remove any debris, the ulnar half of the nail plate and nail bed was left in place, and the radial border was reconstructed. Histology confirmed the clinical diagnosis (Figure 5). No recurrences of the tumor were seen 36 months following surgery.

Figure 2. Macroscopic appearance of the removed nail plate and tumor.

Figure 3. Reflection of the proximal nail fold revealed projections arising from the nail matrix.

Figure 4. When bisected, the nail plate exhibited multiple channels formed by fine filiform projections.

Comment

Since the original report of this tumor,¹ fewer than 10 cases of onychomatricoma have been reported in Latin America,^2-5 with no more than 80 cases reported worldwide.⁶ Clinicians and academicians are becoming interested in the topic, which will result in better recognition and more reports in the literature.

The clinical differential diagnosis of onycho-matricoma is extensive,^7,8 but onychomatricoma has characteristic clinical and histopathologic features that allow its separation from other nail disorders and subungual tumors (Table).⁹ There are 4 cardinal clinical signs that suggest a diagnosis of onychomatricoma: (1) banded or diffuse thickening of the nail plate of variable widths; (2) yellowish discoloration of the involved nail plate, often showing fine splinter hemorrhages in the proximal nail portion; (3) transverse overcurvature of the nail; and (4) exposure of a filamentous tufted tumor emerging from the matrix in a funnel-shaped nail by avulsion.¹

Figure 5. Histology revealed multiple filiform projections of dense connective tissue alternating with vertically oriented invaginations covered by nail matrix epithelium (A)(H&E, original magnification ×2.5). Papillomatous cellular fibrous tissue underlying nail matrix epithelium was noted (B)(H&E, original magnification ×10).

Histologic findings of onychomatricoma typically demonstrate a fibroepithelial tumor with a biphasic growth pattern mimicking normal nail matrix histology, including a proximal zone, which corresponds to the base of the fibroepithelial tumor, and a distal zone, which is composed of multiple epithelial digitations that extend into the small cavities present in the attached nail.^10-12 Nevertheless, the anatomic tumor location, the often fragmented aspect of the tissue specimen, and the choice of the section planes may change the typical histologic features seen in onychomatricoma.¹³ Stromal prominence, cellularity, and atypia may vary in individual cases.^10-12

The etiology of onychomatricoma is not yet known. Although it has been suggested that onychomatricoma could be an epithelial and connective tissue hamartoma simulating the nail matrix structure,^1,10 the more recent concept of an epithelial onychogenic tumor with onychogenic mesenchyme will help to clarify its etiology because new histopathologic and immunohistochemical features suggest a neoplastic nature.¹⁴ On the other hand, predisposing factors such as trauma to the nail plate and onychomycosis may play a role,⁷ as the thumbs, index fingers, and great toes are more susceptible to onychomycosis and accidental trauma.

Conclusion

Our patient fulfilled the criteria of onychomatricoma.¹ Onychomatricoma should be kept in mind in the differential diagnosis of subungual or  periungual tumors to avoid misdiagnosis and erroneous treatments.

Changes in the appearance of the nail apparatus can be produced by a variety of conditions. Onychomatricoma is an unusual benign tumor with specific clinical characteristics that was first described more than 2 decades ago.¹ It is often and easily misdiagnosed because the condition rarely has been described. We report a case of onychomatricoma in a 54-year-old Colombian man who presented with a deformity of the nail plate on the right index finger that corresponded with the classic description of onychomatricoma. We emphasize the importance of reporting such lesions to prevent misdiagnosis and delay of proper treatment.

Case Report

A 54-year-old Colombian man presented with nail dystrophy involving the right index finger of 2 years’ duration. He did not recall any trauma prior to the onset of the nail abnormalities. Several topical treatments had previously been ineffective. Physical examination revealed a longitudinally banded thickening of the lateral half of the nail plate on the right index finger with yellowish brown discoloration, transverse overcurvature of the nail, longitudinal white lines, and splinter hemorrhages (Figure 1). Direct microscopy and fungal culture were performed to diagnose or rule out onychomycosis.

Figure 1. Clinically dystrophic nail with transverse overcurvature, thickening, yellow discoloration of the nail plate, longitudinal bands, and splinter hemorrhages on the right index finger.

A clinical diagnosis of onychomatricoma was made, and the lesion was surgically removed and sent for histopathologic study (Figure 2). The radial half of the nail plate was avulsed, and the proximal part of the removed nail plate contained a large, firmly attached, filamentous tumor arising from the nail matrix (Figure 3) with multiple fine filiform projections (Figure 4). The nail bed was cleaned with a curette to remove any debris, the ulnar half of the nail plate and nail bed was left in place, and the radial border was reconstructed. Histology confirmed the clinical diagnosis (Figure 5). No recurrences of the tumor were seen 36 months following surgery.

Figure 2. Macroscopic appearance of the removed nail plate and tumor.

Figure 3. Reflection of the proximal nail fold revealed projections arising from the nail matrix.

Figure 4. When bisected, the nail plate exhibited multiple channels formed by fine filiform projections.

Comment

Since the original report of this tumor,¹ fewer than 10 cases of onychomatricoma have been reported in Latin America,^2-5 with no more than 80 cases reported worldwide.⁶ Clinicians and academicians are becoming interested in the topic, which will result in better recognition and more reports in the literature.

The clinical differential diagnosis of onycho-matricoma is extensive,^7,8 but onychomatricoma has characteristic clinical and histopathologic features that allow its separation from other nail disorders and subungual tumors (Table).⁹ There are 4 cardinal clinical signs that suggest a diagnosis of onychomatricoma: (1) banded or diffuse thickening of the nail plate of variable widths; (2) yellowish discoloration of the involved nail plate, often showing fine splinter hemorrhages in the proximal nail portion; (3) transverse overcurvature of the nail; and (4) exposure of a filamentous tufted tumor emerging from the matrix in a funnel-shaped nail by avulsion.¹

Figure 5. Histology revealed multiple filiform projections of dense connective tissue alternating with vertically oriented invaginations covered by nail matrix epithelium (A)(H&E, original magnification ×2.5). Papillomatous cellular fibrous tissue underlying nail matrix epithelium was noted (B)(H&E, original magnification ×10).

Histologic findings of onychomatricoma typically demonstrate a fibroepithelial tumor with a biphasic growth pattern mimicking normal nail matrix histology, including a proximal zone, which corresponds to the base of the fibroepithelial tumor, and a distal zone, which is composed of multiple epithelial digitations that extend into the small cavities present in the attached nail.^10-12 Nevertheless, the anatomic tumor location, the often fragmented aspect of the tissue specimen, and the choice of the section planes may change the typical histologic features seen in onychomatricoma.¹³ Stromal prominence, cellularity, and atypia may vary in individual cases.^10-12

The etiology of onychomatricoma is not yet known. Although it has been suggested that onychomatricoma could be an epithelial and connective tissue hamartoma simulating the nail matrix structure,^1,10 the more recent concept of an epithelial onychogenic tumor with onychogenic mesenchyme will help to clarify its etiology because new histopathologic and immunohistochemical features suggest a neoplastic nature.¹⁴ On the other hand, predisposing factors such as trauma to the nail plate and onychomycosis may play a role,⁷ as the thumbs, index fingers, and great toes are more susceptible to onychomycosis and accidental trauma.

Conclusion

Our patient fulfilled the criteria of onychomatricoma.¹ Onychomatricoma should be kept in mind in the differential diagnosis of subungual or  periungual tumors to avoid misdiagnosis and erroneous treatments.

Cutaneous North American blastomycosis is a deep fungal infection caused by Blastomyces dermatitidis, a thermally dimorphic fungus that is endemic to the Great Lakes region as well as the Mississippi and Ohio River valleys where it thrives in moist acidic soil enriched with organic material.^1,2 In humans, the annual incidence rate is estimated to be 0.6 cases per million,³ though it may be as high as 42 cases per 100,000 in endemic areas.⁴ Infection typically results from the inhalation of conidia and manifests as either acute or chronic pneumonia.⁵ Most patients with acute disease present with nonspecific flulike symptoms and a nonproductive cough.

Dissemination occurs in approximately 25% of cases,⁶ most commonly affecting the skin. Other potential sites of dissemination include bone, the genitourinary tract, and the central nervous system. Cutaneous lesions, which may be either verrucous or ulcerative plaques, often occur on or around orifices contiguous to the respiratory tract.⁷ Verrucous lesions tend to have an irregular shape with well-defined borders and surface crusting. Ulcerative lesions have heaped-up borders and often have an exudative base.⁸ The differential diagnosis of cutaneous North American blastomycosis lesions includes squamous cell carcinoma, giant keratoacanthoma, verrucae, basal cell carcinoma, scrofuloderma, lupus vulgaris, nocardiosis, syphilis, bromoderma, iododerma, granuloma inguinale, tuberculosis verrucosa cutis, mycetoma, and actinomycosis.^7,8

Although periorificial cutaneous manifestations of disseminated blastomycosis are common, perianal lesions are rare. The differential diagnosis of  perianal verrucous plaques includes condyloma acuminatum, squamous cell carcinoma, adenocarcinoma, Buschke-Löwenstein tumor, actinomycosis, and localized fungal infections such as blastomycosis.⁹

Case Report

A 57-year-old man presented with a palpable perianal mass that produced small amounts of blood in his underwear and on toilet paper. The patient reported no history of hemorrhoids, anoreceptive intercourse, or sexually transmitted disease. Four months prior to presentation, he had a prolonged upper respiratory tract illness with a subjective fever and productive cough of 2 months’ duration. The patient described himself as an avid outdoorsman who worked at a summer resort and spent a great deal of time in the forests of central Wisconsin last autumn. Physical examination revealed a well-demarcated, firm, moist plaque with a verrucous surface that measured 3.5×2.7 cm and extended from the anal verge to the perianal skin (Figure 1).

Figure 1. A well-demarcated, firm, moist plaque with a verrucous surface extended from the anal verge to the perianal skin.

Potassium hydroxide preparation of a biopsy specimen (Figure 2), a punch biopsy of the lesion (Figure 3), and Gomori methenamine-silver staining (Figure 4) revealed scattered yeast spores, some demonstrating broad-based budding, with pseudoepitheliomatous hyperplasia, dermal neutrophils, and intraepithelial microabscesses. The patient’s urine was positive for Blastomyces antigen (1.04 ng/mL). Chest radiography demonstrated a localized infiltrate in the right hilum with possible mass effect. Computed tomography showed a consolidative opacity measuring 4.0×3.4 cm in the upper lobe of the right lung (Figure 5).

Figure 2. A biopsy specimen prepared with potassium hydroxide showed broad-based, figure eight–shaped budding yeast spores above the arrowhead (original magnification ×600).

Figure 3. A punch biopsy of the lesion revealed scattered yeast spores, some demonstrating broad-based budding, with pseudoepitheliomatous hyperplasia and microabscesses (H&E, original magnification ×400).

The patient was diagnosed with cutaneous North American blastomycosis and prescribed a 6-month course of oral itraconazole 200 mg twice daily. At his 3-month follow-up visit, the perianal plaque hadalmost completely resolved (Figure 6). However, because the patient had increasing lower extremity edema, subjective hearing loss, and abnormal liver function tests, itraconazole treatment was discontinued and replaced with oral fluconazole 400 mg daily for the next 3 months. The right hilar mass had visibly improved on follow-up chest radiography 2 months after the patient started antifungal therapy with itraconazole and had resolved within another 3 months of treatment.

Figure 4. Gomori methenamine-silver stain demonstrated broad-based budding yeast (original magnification ×400).

Figure 5. Computed tomography revealed a consolidative opacity measuring 4.0×3.4 cm in the upper lobe of the right lung.

Comment

Cutaneous blastomycosis results most often from the hematogenous spread of B dermatitidis from the lungs and rarely from direct inoculation.^5,10 Skin lesions tend to occur on exposed areas, such as the face, scalp, hands, wrists, feet, and ankles.^7,11-13 Dissemination to the perianal skin is rare, though it has been reported in 2 other patients; both patients, similar to our patient, had evidence of pulmonary involvement at some point in their clinical course.^9,14

Figure 6. The perianal plaque had almost completely resolved after 3 months of oral itraconazole therapy.

Diagnosis is based on identification of  B dermatitidis by microscopy or culture. Potassium hydroxide preparation of biopsy specimens typically shows broad-based budding yeast.¹³ Characteristic findings of histopathologic studies include pseudo-epitheliomatous hyperplasia, intraepidermal abscesses, and a dermal infiltrate of polymorphonuclear  leukocytes.¹⁵ On fungal culture, B dermatitidis is  slow growing and may require a 2- to 4-week incubation period. Serologic tests are available, but sensitivity is low, at 9%, 28%, and 77% for complement fixation, immunodiffusion, and enzyme immunoassay, respectively.¹⁶

Conclusion

North American blastomycosis should be considered in patients who have verrucous or ulcerative perianal lesions and have lived in or traveled to endemic regions, especially if they have recent or ongoing pulmonary symptoms. Potassium hydroxide preparation and fungal staining of biopsy specimens can aid in diagnosis.

Acknowledgment

The authors thank the Marshfield Clinic Research Foundation’s Office of Scientific Writing and Publication (Marshfield, Wisconsin) for editorial assistance in the preparation of  this manuscript.

Cutaneous North American blastomycosis is a deep fungal infection caused by Blastomyces dermatitidis, a thermally dimorphic fungus that is endemic to the Great Lakes region as well as the Mississippi and Ohio River valleys where it thrives in moist acidic soil enriched with organic material.^1,2 In humans, the annual incidence rate is estimated to be 0.6 cases per million,³ though it may be as high as 42 cases per 100,000 in endemic areas.⁴ Infection typically results from the inhalation of conidia and manifests as either acute or chronic pneumonia.⁵ Most patients with acute disease present with nonspecific flulike symptoms and a nonproductive cough.

Dissemination occurs in approximately 25% of cases,⁶ most commonly affecting the skin. Other potential sites of dissemination include bone, the genitourinary tract, and the central nervous system. Cutaneous lesions, which may be either verrucous or ulcerative plaques, often occur on or around orifices contiguous to the respiratory tract.⁷ Verrucous lesions tend to have an irregular shape with well-defined borders and surface crusting. Ulcerative lesions have heaped-up borders and often have an exudative base.⁸ The differential diagnosis of cutaneous North American blastomycosis lesions includes squamous cell carcinoma, giant keratoacanthoma, verrucae, basal cell carcinoma, scrofuloderma, lupus vulgaris, nocardiosis, syphilis, bromoderma, iododerma, granuloma inguinale, tuberculosis verrucosa cutis, mycetoma, and actinomycosis.^7,8

Although periorificial cutaneous manifestations of disseminated blastomycosis are common, perianal lesions are rare. The differential diagnosis of  perianal verrucous plaques includes condyloma acuminatum, squamous cell carcinoma, adenocarcinoma, Buschke-Löwenstein tumor, actinomycosis, and localized fungal infections such as blastomycosis.⁹

Case Report

A 57-year-old man presented with a palpable perianal mass that produced small amounts of blood in his underwear and on toilet paper. The patient reported no history of hemorrhoids, anoreceptive intercourse, or sexually transmitted disease. Four months prior to presentation, he had a prolonged upper respiratory tract illness with a subjective fever and productive cough of 2 months’ duration. The patient described himself as an avid outdoorsman who worked at a summer resort and spent a great deal of time in the forests of central Wisconsin last autumn. Physical examination revealed a well-demarcated, firm, moist plaque with a verrucous surface that measured 3.5×2.7 cm and extended from the anal verge to the perianal skin (Figure 1).

Figure 1. A well-demarcated, firm, moist plaque with a verrucous surface extended from the anal verge to the perianal skin.

Potassium hydroxide preparation of a biopsy specimen (Figure 2), a punch biopsy of the lesion (Figure 3), and Gomori methenamine-silver staining (Figure 4) revealed scattered yeast spores, some demonstrating broad-based budding, with pseudoepitheliomatous hyperplasia, dermal neutrophils, and intraepithelial microabscesses. The patient’s urine was positive for Blastomyces antigen (1.04 ng/mL). Chest radiography demonstrated a localized infiltrate in the right hilum with possible mass effect. Computed tomography showed a consolidative opacity measuring 4.0×3.4 cm in the upper lobe of the right lung (Figure 5).

Figure 2. A biopsy specimen prepared with potassium hydroxide showed broad-based, figure eight–shaped budding yeast spores above the arrowhead (original magnification ×600).

Figure 3. A punch biopsy of the lesion revealed scattered yeast spores, some demonstrating broad-based budding, with pseudoepitheliomatous hyperplasia and microabscesses (H&E, original magnification ×400).

The patient was diagnosed with cutaneous North American blastomycosis and prescribed a 6-month course of oral itraconazole 200 mg twice daily. At his 3-month follow-up visit, the perianal plaque hadalmost completely resolved (Figure 6). However, because the patient had increasing lower extremity edema, subjective hearing loss, and abnormal liver function tests, itraconazole treatment was discontinued and replaced with oral fluconazole 400 mg daily for the next 3 months. The right hilar mass had visibly improved on follow-up chest radiography 2 months after the patient started antifungal therapy with itraconazole and had resolved within another 3 months of treatment.

Figure 4. Gomori methenamine-silver stain demonstrated broad-based budding yeast (original magnification ×400).

Figure 5. Computed tomography revealed a consolidative opacity measuring 4.0×3.4 cm in the upper lobe of the right lung.

Comment

Cutaneous blastomycosis results most often from the hematogenous spread of B dermatitidis from the lungs and rarely from direct inoculation.^5,10 Skin lesions tend to occur on exposed areas, such as the face, scalp, hands, wrists, feet, and ankles.^7,11-13 Dissemination to the perianal skin is rare, though it has been reported in 2 other patients; both patients, similar to our patient, had evidence of pulmonary involvement at some point in their clinical course.^9,14

Figure 6. The perianal plaque had almost completely resolved after 3 months of oral itraconazole therapy.

Diagnosis is based on identification of  B dermatitidis by microscopy or culture. Potassium hydroxide preparation of biopsy specimens typically shows broad-based budding yeast.¹³ Characteristic findings of histopathologic studies include pseudo-epitheliomatous hyperplasia, intraepidermal abscesses, and a dermal infiltrate of polymorphonuclear  leukocytes.¹⁵ On fungal culture, B dermatitidis is  slow growing and may require a 2- to 4-week incubation period. Serologic tests are available, but sensitivity is low, at 9%, 28%, and 77% for complement fixation, immunodiffusion, and enzyme immunoassay, respectively.¹⁶

Conclusion

North American blastomycosis should be considered in patients who have verrucous or ulcerative perianal lesions and have lived in or traveled to endemic regions, especially if they have recent or ongoing pulmonary symptoms. Potassium hydroxide preparation and fungal staining of biopsy specimens can aid in diagnosis.

Acknowledgment

The authors thank the Marshfield Clinic Research Foundation’s Office of Scientific Writing and Publication (Marshfield, Wisconsin) for editorial assistance in the preparation of  this manuscript.

Cutaneous North American blastomycosis is a deep fungal infection caused by Blastomyces dermatitidis, a thermally dimorphic fungus that is endemic to the Great Lakes region as well as the Mississippi and Ohio River valleys where it thrives in moist acidic soil enriched with organic material.^1,2 In humans, the annual incidence rate is estimated to be 0.6 cases per million,³ though it may be as high as 42 cases per 100,000 in endemic areas.⁴ Infection typically results from the inhalation of conidia and manifests as either acute or chronic pneumonia.⁵ Most patients with acute disease present with nonspecific flulike symptoms and a nonproductive cough.

Dissemination occurs in approximately 25% of cases,⁶ most commonly affecting the skin. Other potential sites of dissemination include bone, the genitourinary tract, and the central nervous system. Cutaneous lesions, which may be either verrucous or ulcerative plaques, often occur on or around orifices contiguous to the respiratory tract.⁷ Verrucous lesions tend to have an irregular shape with well-defined borders and surface crusting. Ulcerative lesions have heaped-up borders and often have an exudative base.⁸ The differential diagnosis of cutaneous North American blastomycosis lesions includes squamous cell carcinoma, giant keratoacanthoma, verrucae, basal cell carcinoma, scrofuloderma, lupus vulgaris, nocardiosis, syphilis, bromoderma, iododerma, granuloma inguinale, tuberculosis verrucosa cutis, mycetoma, and actinomycosis.^7,8

Although periorificial cutaneous manifestations of disseminated blastomycosis are common, perianal lesions are rare. The differential diagnosis of  perianal verrucous plaques includes condyloma acuminatum, squamous cell carcinoma, adenocarcinoma, Buschke-Löwenstein tumor, actinomycosis, and localized fungal infections such as blastomycosis.⁹

Case Report

A 57-year-old man presented with a palpable perianal mass that produced small amounts of blood in his underwear and on toilet paper. The patient reported no history of hemorrhoids, anoreceptive intercourse, or sexually transmitted disease. Four months prior to presentation, he had a prolonged upper respiratory tract illness with a subjective fever and productive cough of 2 months’ duration. The patient described himself as an avid outdoorsman who worked at a summer resort and spent a great deal of time in the forests of central Wisconsin last autumn. Physical examination revealed a well-demarcated, firm, moist plaque with a verrucous surface that measured 3.5×2.7 cm and extended from the anal verge to the perianal skin (Figure 1).

Figure 1. A well-demarcated, firm, moist plaque with a verrucous surface extended from the anal verge to the perianal skin.

Potassium hydroxide preparation of a biopsy specimen (Figure 2), a punch biopsy of the lesion (Figure 3), and Gomori methenamine-silver staining (Figure 4) revealed scattered yeast spores, some demonstrating broad-based budding, with pseudoepitheliomatous hyperplasia, dermal neutrophils, and intraepithelial microabscesses. The patient’s urine was positive for Blastomyces antigen (1.04 ng/mL). Chest radiography demonstrated a localized infiltrate in the right hilum with possible mass effect. Computed tomography showed a consolidative opacity measuring 4.0×3.4 cm in the upper lobe of the right lung (Figure 5).

Figure 2. A biopsy specimen prepared with potassium hydroxide showed broad-based, figure eight–shaped budding yeast spores above the arrowhead (original magnification ×600).

Figure 3. A punch biopsy of the lesion revealed scattered yeast spores, some demonstrating broad-based budding, with pseudoepitheliomatous hyperplasia and microabscesses (H&E, original magnification ×400).

The patient was diagnosed with cutaneous North American blastomycosis and prescribed a 6-month course of oral itraconazole 200 mg twice daily. At his 3-month follow-up visit, the perianal plaque hadalmost completely resolved (Figure 6). However, because the patient had increasing lower extremity edema, subjective hearing loss, and abnormal liver function tests, itraconazole treatment was discontinued and replaced with oral fluconazole 400 mg daily for the next 3 months. The right hilar mass had visibly improved on follow-up chest radiography 2 months after the patient started antifungal therapy with itraconazole and had resolved within another 3 months of treatment.

Figure 4. Gomori methenamine-silver stain demonstrated broad-based budding yeast (original magnification ×400).

Figure 5. Computed tomography revealed a consolidative opacity measuring 4.0×3.4 cm in the upper lobe of the right lung.

Comment

Cutaneous blastomycosis results most often from the hematogenous spread of B dermatitidis from the lungs and rarely from direct inoculation.^5,10 Skin lesions tend to occur on exposed areas, such as the face, scalp, hands, wrists, feet, and ankles.^7,11-13 Dissemination to the perianal skin is rare, though it has been reported in 2 other patients; both patients, similar to our patient, had evidence of pulmonary involvement at some point in their clinical course.^9,14

Figure 6. The perianal plaque had almost completely resolved after 3 months of oral itraconazole therapy.

Diagnosis is based on identification of  B dermatitidis by microscopy or culture. Potassium hydroxide preparation of biopsy specimens typically shows broad-based budding yeast.¹³ Characteristic findings of histopathologic studies include pseudo-epitheliomatous hyperplasia, intraepidermal abscesses, and a dermal infiltrate of polymorphonuclear  leukocytes.¹⁵ On fungal culture, B dermatitidis is  slow growing and may require a 2- to 4-week incubation period. Serologic tests are available, but sensitivity is low, at 9%, 28%, and 77% for complement fixation, immunodiffusion, and enzyme immunoassay, respectively.¹⁶

Conclusion

North American blastomycosis should be considered in patients who have verrucous or ulcerative perianal lesions and have lived in or traveled to endemic regions, especially if they have recent or ongoing pulmonary symptoms. Potassium hydroxide preparation and fungal staining of biopsy specimens can aid in diagnosis.

Acknowledgment

The authors thank the Marshfield Clinic Research Foundation’s Office of Scientific Writing and Publication (Marshfield, Wisconsin) for editorial assistance in the preparation of  this manuscript.

The anterior cruciate ligament (ACL) restrains anterior translation of the tibia on the femur and controls rotation of the knee. The natural primary healing potential of the ACL has been extremely poor in clinical and experimental studies, and primary suture repair has not provided stability to the joint in most patients.^1-8 This has led surgeons to reconstruct the ACL, rather than to attempt nonoperative treatment. Anterior cruciate ligament reconstruction is recommended to help patients maintain activities that place shear and torque forces on the knee or to ameliorate persistent pain due to instability.⁹ Reconstruction of the ACL in adults is one of the most common procedures performed by orthopedic surgeons. However, reconstruction in the ACL-deficient adolescent remains a controversial subject, with debates surrounding operative timing and surgical technique.

This case report presents a skeletally immature patient who suffered a complete traumatic rupture of his ACL, which intrinsically healed. The patient had a protracted treatment course, complicated by an open tibial fracture with delayed union. He responded to a progressive rehabilitation program and has made a good functional recovery. Review of the literature has demonstrated limited evidence of intrinsic ACL healing, none of which has been shown to occur in a skeletally immature patient. The patient’s mother provided written informed consent for print and electronic publication of this case report.

Case Report

A 12-year-old boy was brought to our level I trauma center by ambulance after being hit by a car while riding a motorized scooter. He presented with a grade IIIB open tibial fracture and a distal fibula fracture of his left lower extremity and was taken to the operating room that night for irrigation and débridement, percutaneous fixation of the fibula, and intramedullary flexible nail fixation of the tibia. On postoperative day 1, he had increasing pain and, once his splint was removed, his compartments were found to be very tense. He was taken emergently to the operating room for 4 compartment fasciotomies of the left lower extremity with wound vacuum-assisted closure (VAC) placement. This was changed on hospital day 4 and was removed with definitive closure on day 7. Examination under anesthesia prior to the final wound VAC change was performed given the patient’s complaints during physical therapy. This showed anterior and posterior ligamentous instability of the knee, and he was placed in a knee immobilizer. He was discharged on hospital day 11.

At 2-week follow-up, the patient was doing well, except that he was nonadherent with the knee immobilizer and unable to fully extend his left knee. On examination, a posterior drawer sign was noted; therefore, the patient was referred for magnetic resonance imaging (MRI) to evaluate his ligaments. His MRI, 9 weeks after injury, showed: (1) complete tears of both the anterior and posterior cruciate ligaments (PCLs) (Figures 1A, 1B); (2) medial meniscus and lateral meniscus tears; (3) 2.0-cm plate-like avulsion fracture of the posterolateral femoral metaphysis involving the insertion of the lateral head of the gastrocnemius muscle, fibular collateral ligament, and popliteus muscle (Figure 2); and (4) left posterior lateral tibial plateau contusion.

The patient was started on a 6-week course of physical therapy with active and active-assisted extension exercises. At follow-up approximately 3½ months after injury, he was found to have a 35º flexion contracture with pain at the end extension. Unfortunately, his tibial fracture showed minimal signs of healing, and the decision was made to delay surgical intervention on the knee until the tibial fracture had healed. He was given a knee orthotic to wear at night to help regain his knee extension.

Six months after injury, the patient underwent open removal of the avulsed bony fragment, posterior knee capsule release, and autograft of the delayed union tibial fracture. He was placed in a straight leg cast postoperatively and was discharged home on postoperative day 2. He transitioned to a knee immobilizer after 2 weeks. Six weeks after the last surgery, he had range of motion of 0º to 130º. Ligamentous examination at this time showed anterior and posterior drawer signs, positive Lachman test, and dial test with 90º of external rotation. He was placed in physical therapy for a total of 10 weeks to work on his quadriceps muscle strength and 15º extension lag.

On 13-month postinjury radiographs, the patient was noted to have adequate healing of his tibial fracture, and ligamentous reconstruction was discussed. At this time, the patient did not have any instability or pain in the knee. Examination demonstrated a very mild effusion of the left knee. Range of motion determined by goniometer was from -3º to 140º, and Lachman test was positive but with solid 2+ endpoint. He also had a positive posterior drawer sign with no endpoint, positive sag sign of his tibia, and positive active quadriceps test of the left leg. His dial test showed some increased external rotation at 90º but was equivocal at 30º when compared with the contralateral knee, demonstrating involvement of the posterolateral corner.

Sixteen months after injury, repeat MRI to further evaluate the posterolateral corner showed: (1) complete medial and lateral meniscal healing without evidence of residual or recurrent tear, and (2) interval healing of the remote ACL and PCL tears with intact insertions (Figures 3A, 3B). This scan showed an end-to-end continuous ACL with homogeneous signal and disappearance of the secondary signs. Physical examination at this time showed a very firm endpoint on Lachman test but some laxity with his posterior drawer. Given these findings, the patient was given a brace and continued in physical therapy to strengthen his quadriceps muscle. By 20 months after injury, he had returned to competitive hockey and had no complaints of pain or instability. His physical examination showed full range of motion in a ligamentously stable knee with firm endpoint. The patient’s condition was unchanged at 29-month follow-up.

Discussion

There is a body of evidence that states a completely ruptured ACL does not heal.^3,6,10 In animal models, the ACL has been shown to have poor healing potential.^3,11 Some studies have suggested this is secondary to poor blood supply. Blood supply to the ACL is derived from a periligamentous, then endoligamentous, arterial network with a less vascularized area in the middle third of the ACL. Additionally, there is no blood supply from the tibia or femur, meaning the areas of attachment of the ligament are poorly vascularized.¹² With a minimal blood supply to the ACL, the supply of undifferentiated mesenchymal cells from the surrounding tissue during the initial healing process is limited. In vitro cell cultures of these cells have showed a reduced potential for proliferation and migration.⁹ Cells of the ACL have a lower response to growth factors than human medial collateral ligament cells, further suggesting a decreased reparative capacity.⁷ Joint fluid has been shown to inhibit the proliferation of these cells, further reducing their regenerative potential.¹³ Additionally, biomechanical factors that alter signaling pathways, sites of ligament reattachment, and injury to proprioceptive structures have been shown to negatively influence the healing response.^14-18

Review of the literature on healing of ACLs includes 2 case reports, totaling 3 patients, and 3 level IV therapeutic studies involving 74 patients total.^10,19-22 In most cases, the authors of these studies have indicated a nonoperative treatment protocol with bracing and a specific rehabilitation program. Malanga and colleagues¹⁰ demonstrated that an ACL torn from its attachment on the femur, with the majority of the ligament in good condition and no compromise in the length, healed back onto the femur. Kurosaka and coauthors²⁰ described case reports of isolated distal or proximal midsubstance tears that have healed spontaneously. However, none of the patients described in the literature were under the age of 20 years.

Treatment for pediatric patients with open physes causes some debate. Nonoperative management of ACL deficiency in adolescents is generally not recommended because the continued instability of the joint leads to intra-articular injury, functional impairment, and joint degeneration.^23-25 A recent systematic review found only 1 study that showed no increase in secondary intra-articular injury when surgery was delayed until skeletal maturity.²⁶ 

Our patient was a 12-year-old boy whose traumatic knee injury with multiple ruptured ligaments healed over the course of 20 months. It is likely that bracing associated with the patient’s second surgery and delayed union of his tibial fracture allowed healing tissue to be protected from excessive stress until it remodeled with sufficient strength. Most would assume that healing would occur early, during the first 6 to 9 months; however, our patient regained his stability between 8 and 13 months. It is possible that the hostile healing environment of the ACL, including the low blood supply, poor response to growth factors, and biomechanical environment, as described previously, played a factor in this delay.^7,9,12,13

It is important to recognize that our patient tore his ACL during a traumatic motorized scooter rollover collision, not the more common noncontact twisting injury. Additionally, given the patient’s knee surgery that was performed 6 months after the initial injury, it is possible that intra-articular scar formation contributed to his healing capacity. While this patient did not undergo arthroscopy to visualize the tear in the ACL, or its reconstitution, recent evidence suggests that the accuracy of MRI in diagnosing pediatric ACL injuries is excellent.^27,28 The diagnostic accuracy with new MRI machines has sensitivity and specificity approaching 100%.²⁹ Additionally, the patient’s subjective and objective improvements argue for a change in anatomy over a change in the quality of his examination.

Conclusion

The goal of ACL reconstruction in adolescents is to provide long-term stability to the knee while minimizing the risk of growth disturbance. This goal was achieved in our patient through the in situ healing of his ACL. Intrinsic reconstitution of a torn ACL is rare, and it is difficult to speculate which patients may have some healing potential. While this patient was an extreme example, his case demonstrated that protection of the knee from undue stress could favorably alter the environment of the knee to allow for healing of ACL tears. Such information could be valuable in managing select pediatric patients with open physes and ACL injuries nonoperatively, sparing them from the risks associated with surgical treatment. While we do not recommend nonoperative treatment for patients with acute tears of the ACL, we believe more investigation into the healing potential of the ACL, and potential pathways to augment this, is warranted.

The anterior cruciate ligament (ACL) restrains anterior translation of the tibia on the femur and controls rotation of the knee. The natural primary healing potential of the ACL has been extremely poor in clinical and experimental studies, and primary suture repair has not provided stability to the joint in most patients.^1-8 This has led surgeons to reconstruct the ACL, rather than to attempt nonoperative treatment. Anterior cruciate ligament reconstruction is recommended to help patients maintain activities that place shear and torque forces on the knee or to ameliorate persistent pain due to instability.⁹ Reconstruction of the ACL in adults is one of the most common procedures performed by orthopedic surgeons. However, reconstruction in the ACL-deficient adolescent remains a controversial subject, with debates surrounding operative timing and surgical technique.

This case report presents a skeletally immature patient who suffered a complete traumatic rupture of his ACL, which intrinsically healed. The patient had a protracted treatment course, complicated by an open tibial fracture with delayed union. He responded to a progressive rehabilitation program and has made a good functional recovery. Review of the literature has demonstrated limited evidence of intrinsic ACL healing, none of which has been shown to occur in a skeletally immature patient. The patient’s mother provided written informed consent for print and electronic publication of this case report.

Case Report

A 12-year-old boy was brought to our level I trauma center by ambulance after being hit by a car while riding a motorized scooter. He presented with a grade IIIB open tibial fracture and a distal fibula fracture of his left lower extremity and was taken to the operating room that night for irrigation and débridement, percutaneous fixation of the fibula, and intramedullary flexible nail fixation of the tibia. On postoperative day 1, he had increasing pain and, once his splint was removed, his compartments were found to be very tense. He was taken emergently to the operating room for 4 compartment fasciotomies of the left lower extremity with wound vacuum-assisted closure (VAC) placement. This was changed on hospital day 4 and was removed with definitive closure on day 7. Examination under anesthesia prior to the final wound VAC change was performed given the patient’s complaints during physical therapy. This showed anterior and posterior ligamentous instability of the knee, and he was placed in a knee immobilizer. He was discharged on hospital day 11.

At 2-week follow-up, the patient was doing well, except that he was nonadherent with the knee immobilizer and unable to fully extend his left knee. On examination, a posterior drawer sign was noted; therefore, the patient was referred for magnetic resonance imaging (MRI) to evaluate his ligaments. His MRI, 9 weeks after injury, showed: (1) complete tears of both the anterior and posterior cruciate ligaments (PCLs) (Figures 1A, 1B); (2) medial meniscus and lateral meniscus tears; (3) 2.0-cm plate-like avulsion fracture of the posterolateral femoral metaphysis involving the insertion of the lateral head of the gastrocnemius muscle, fibular collateral ligament, and popliteus muscle (Figure 2); and (4) left posterior lateral tibial plateau contusion.

The patient was started on a 6-week course of physical therapy with active and active-assisted extension exercises. At follow-up approximately 3½ months after injury, he was found to have a 35º flexion contracture with pain at the end extension. Unfortunately, his tibial fracture showed minimal signs of healing, and the decision was made to delay surgical intervention on the knee until the tibial fracture had healed. He was given a knee orthotic to wear at night to help regain his knee extension.

Six months after injury, the patient underwent open removal of the avulsed bony fragment, posterior knee capsule release, and autograft of the delayed union tibial fracture. He was placed in a straight leg cast postoperatively and was discharged home on postoperative day 2. He transitioned to a knee immobilizer after 2 weeks. Six weeks after the last surgery, he had range of motion of 0º to 130º. Ligamentous examination at this time showed anterior and posterior drawer signs, positive Lachman test, and dial test with 90º of external rotation. He was placed in physical therapy for a total of 10 weeks to work on his quadriceps muscle strength and 15º extension lag.

On 13-month postinjury radiographs, the patient was noted to have adequate healing of his tibial fracture, and ligamentous reconstruction was discussed. At this time, the patient did not have any instability or pain in the knee. Examination demonstrated a very mild effusion of the left knee. Range of motion determined by goniometer was from -3º to 140º, and Lachman test was positive but with solid 2+ endpoint. He also had a positive posterior drawer sign with no endpoint, positive sag sign of his tibia, and positive active quadriceps test of the left leg. His dial test showed some increased external rotation at 90º but was equivocal at 30º when compared with the contralateral knee, demonstrating involvement of the posterolateral corner.

Sixteen months after injury, repeat MRI to further evaluate the posterolateral corner showed: (1) complete medial and lateral meniscal healing without evidence of residual or recurrent tear, and (2) interval healing of the remote ACL and PCL tears with intact insertions (Figures 3A, 3B). This scan showed an end-to-end continuous ACL with homogeneous signal and disappearance of the secondary signs. Physical examination at this time showed a very firm endpoint on Lachman test but some laxity with his posterior drawer. Given these findings, the patient was given a brace and continued in physical therapy to strengthen his quadriceps muscle. By 20 months after injury, he had returned to competitive hockey and had no complaints of pain or instability. His physical examination showed full range of motion in a ligamentously stable knee with firm endpoint. The patient’s condition was unchanged at 29-month follow-up.

Discussion

There is a body of evidence that states a completely ruptured ACL does not heal.^3,6,10 In animal models, the ACL has been shown to have poor healing potential.^3,11 Some studies have suggested this is secondary to poor blood supply. Blood supply to the ACL is derived from a periligamentous, then endoligamentous, arterial network with a less vascularized area in the middle third of the ACL. Additionally, there is no blood supply from the tibia or femur, meaning the areas of attachment of the ligament are poorly vascularized.¹² With a minimal blood supply to the ACL, the supply of undifferentiated mesenchymal cells from the surrounding tissue during the initial healing process is limited. In vitro cell cultures of these cells have showed a reduced potential for proliferation and migration.⁹ Cells of the ACL have a lower response to growth factors than human medial collateral ligament cells, further suggesting a decreased reparative capacity.⁷ Joint fluid has been shown to inhibit the proliferation of these cells, further reducing their regenerative potential.¹³ Additionally, biomechanical factors that alter signaling pathways, sites of ligament reattachment, and injury to proprioceptive structures have been shown to negatively influence the healing response.^14-18

Review of the literature on healing of ACLs includes 2 case reports, totaling 3 patients, and 3 level IV therapeutic studies involving 74 patients total.^10,19-22 In most cases, the authors of these studies have indicated a nonoperative treatment protocol with bracing and a specific rehabilitation program. Malanga and colleagues¹⁰ demonstrated that an ACL torn from its attachment on the femur, with the majority of the ligament in good condition and no compromise in the length, healed back onto the femur. Kurosaka and coauthors²⁰ described case reports of isolated distal or proximal midsubstance tears that have healed spontaneously. However, none of the patients described in the literature were under the age of 20 years.

Treatment for pediatric patients with open physes causes some debate. Nonoperative management of ACL deficiency in adolescents is generally not recommended because the continued instability of the joint leads to intra-articular injury, functional impairment, and joint degeneration.^23-25 A recent systematic review found only 1 study that showed no increase in secondary intra-articular injury when surgery was delayed until skeletal maturity.²⁶ 

Our patient was a 12-year-old boy whose traumatic knee injury with multiple ruptured ligaments healed over the course of 20 months. It is likely that bracing associated with the patient’s second surgery and delayed union of his tibial fracture allowed healing tissue to be protected from excessive stress until it remodeled with sufficient strength. Most would assume that healing would occur early, during the first 6 to 9 months; however, our patient regained his stability between 8 and 13 months. It is possible that the hostile healing environment of the ACL, including the low blood supply, poor response to growth factors, and biomechanical environment, as described previously, played a factor in this delay.^7,9,12,13

It is important to recognize that our patient tore his ACL during a traumatic motorized scooter rollover collision, not the more common noncontact twisting injury. Additionally, given the patient’s knee surgery that was performed 6 months after the initial injury, it is possible that intra-articular scar formation contributed to his healing capacity. While this patient did not undergo arthroscopy to visualize the tear in the ACL, or its reconstitution, recent evidence suggests that the accuracy of MRI in diagnosing pediatric ACL injuries is excellent.^27,28 The diagnostic accuracy with new MRI machines has sensitivity and specificity approaching 100%.²⁹ Additionally, the patient’s subjective and objective improvements argue for a change in anatomy over a change in the quality of his examination.

Conclusion

The goal of ACL reconstruction in adolescents is to provide long-term stability to the knee while minimizing the risk of growth disturbance. This goal was achieved in our patient through the in situ healing of his ACL. Intrinsic reconstitution of a torn ACL is rare, and it is difficult to speculate which patients may have some healing potential. While this patient was an extreme example, his case demonstrated that protection of the knee from undue stress could favorably alter the environment of the knee to allow for healing of ACL tears. Such information could be valuable in managing select pediatric patients with open physes and ACL injuries nonoperatively, sparing them from the risks associated with surgical treatment. While we do not recommend nonoperative treatment for patients with acute tears of the ACL, we believe more investigation into the healing potential of the ACL, and potential pathways to augment this, is warranted.

The anterior cruciate ligament (ACL) restrains anterior translation of the tibia on the femur and controls rotation of the knee. The natural primary healing potential of the ACL has been extremely poor in clinical and experimental studies, and primary suture repair has not provided stability to the joint in most patients.^1-8 This has led surgeons to reconstruct the ACL, rather than to attempt nonoperative treatment. Anterior cruciate ligament reconstruction is recommended to help patients maintain activities that place shear and torque forces on the knee or to ameliorate persistent pain due to instability.⁹ Reconstruction of the ACL in adults is one of the most common procedures performed by orthopedic surgeons. However, reconstruction in the ACL-deficient adolescent remains a controversial subject, with debates surrounding operative timing and surgical technique.

This case report presents a skeletally immature patient who suffered a complete traumatic rupture of his ACL, which intrinsically healed. The patient had a protracted treatment course, complicated by an open tibial fracture with delayed union. He responded to a progressive rehabilitation program and has made a good functional recovery. Review of the literature has demonstrated limited evidence of intrinsic ACL healing, none of which has been shown to occur in a skeletally immature patient. The patient’s mother provided written informed consent for print and electronic publication of this case report.

Case Report

A 12-year-old boy was brought to our level I trauma center by ambulance after being hit by a car while riding a motorized scooter. He presented with a grade IIIB open tibial fracture and a distal fibula fracture of his left lower extremity and was taken to the operating room that night for irrigation and débridement, percutaneous fixation of the fibula, and intramedullary flexible nail fixation of the tibia. On postoperative day 1, he had increasing pain and, once his splint was removed, his compartments were found to be very tense. He was taken emergently to the operating room for 4 compartment fasciotomies of the left lower extremity with wound vacuum-assisted closure (VAC) placement. This was changed on hospital day 4 and was removed with definitive closure on day 7. Examination under anesthesia prior to the final wound VAC change was performed given the patient’s complaints during physical therapy. This showed anterior and posterior ligamentous instability of the knee, and he was placed in a knee immobilizer. He was discharged on hospital day 11.

At 2-week follow-up, the patient was doing well, except that he was nonadherent with the knee immobilizer and unable to fully extend his left knee. On examination, a posterior drawer sign was noted; therefore, the patient was referred for magnetic resonance imaging (MRI) to evaluate his ligaments. His MRI, 9 weeks after injury, showed: (1) complete tears of both the anterior and posterior cruciate ligaments (PCLs) (Figures 1A, 1B); (2) medial meniscus and lateral meniscus tears; (3) 2.0-cm plate-like avulsion fracture of the posterolateral femoral metaphysis involving the insertion of the lateral head of the gastrocnemius muscle, fibular collateral ligament, and popliteus muscle (Figure 2); and (4) left posterior lateral tibial plateau contusion.

The patient was started on a 6-week course of physical therapy with active and active-assisted extension exercises. At follow-up approximately 3½ months after injury, he was found to have a 35º flexion contracture with pain at the end extension. Unfortunately, his tibial fracture showed minimal signs of healing, and the decision was made to delay surgical intervention on the knee until the tibial fracture had healed. He was given a knee orthotic to wear at night to help regain his knee extension.

Six months after injury, the patient underwent open removal of the avulsed bony fragment, posterior knee capsule release, and autograft of the delayed union tibial fracture. He was placed in a straight leg cast postoperatively and was discharged home on postoperative day 2. He transitioned to a knee immobilizer after 2 weeks. Six weeks after the last surgery, he had range of motion of 0º to 130º. Ligamentous examination at this time showed anterior and posterior drawer signs, positive Lachman test, and dial test with 90º of external rotation. He was placed in physical therapy for a total of 10 weeks to work on his quadriceps muscle strength and 15º extension lag.

On 13-month postinjury radiographs, the patient was noted to have adequate healing of his tibial fracture, and ligamentous reconstruction was discussed. At this time, the patient did not have any instability or pain in the knee. Examination demonstrated a very mild effusion of the left knee. Range of motion determined by goniometer was from -3º to 140º, and Lachman test was positive but with solid 2+ endpoint. He also had a positive posterior drawer sign with no endpoint, positive sag sign of his tibia, and positive active quadriceps test of the left leg. His dial test showed some increased external rotation at 90º but was equivocal at 30º when compared with the contralateral knee, demonstrating involvement of the posterolateral corner.

Sixteen months after injury, repeat MRI to further evaluate the posterolateral corner showed: (1) complete medial and lateral meniscal healing without evidence of residual or recurrent tear, and (2) interval healing of the remote ACL and PCL tears with intact insertions (Figures 3A, 3B). This scan showed an end-to-end continuous ACL with homogeneous signal and disappearance of the secondary signs. Physical examination at this time showed a very firm endpoint on Lachman test but some laxity with his posterior drawer. Given these findings, the patient was given a brace and continued in physical therapy to strengthen his quadriceps muscle. By 20 months after injury, he had returned to competitive hockey and had no complaints of pain or instability. His physical examination showed full range of motion in a ligamentously stable knee with firm endpoint. The patient’s condition was unchanged at 29-month follow-up.

Discussion

There is a body of evidence that states a completely ruptured ACL does not heal.^3,6,10 In animal models, the ACL has been shown to have poor healing potential.^3,11 Some studies have suggested this is secondary to poor blood supply. Blood supply to the ACL is derived from a periligamentous, then endoligamentous, arterial network with a less vascularized area in the middle third of the ACL. Additionally, there is no blood supply from the tibia or femur, meaning the areas of attachment of the ligament are poorly vascularized.¹² With a minimal blood supply to the ACL, the supply of undifferentiated mesenchymal cells from the surrounding tissue during the initial healing process is limited. In vitro cell cultures of these cells have showed a reduced potential for proliferation and migration.⁹ Cells of the ACL have a lower response to growth factors than human medial collateral ligament cells, further suggesting a decreased reparative capacity.⁷ Joint fluid has been shown to inhibit the proliferation of these cells, further reducing their regenerative potential.¹³ Additionally, biomechanical factors that alter signaling pathways, sites of ligament reattachment, and injury to proprioceptive structures have been shown to negatively influence the healing response.^14-18

Review of the literature on healing of ACLs includes 2 case reports, totaling 3 patients, and 3 level IV therapeutic studies involving 74 patients total.^10,19-22 In most cases, the authors of these studies have indicated a nonoperative treatment protocol with bracing and a specific rehabilitation program. Malanga and colleagues¹⁰ demonstrated that an ACL torn from its attachment on the femur, with the majority of the ligament in good condition and no compromise in the length, healed back onto the femur. Kurosaka and coauthors²⁰ described case reports of isolated distal or proximal midsubstance tears that have healed spontaneously. However, none of the patients described in the literature were under the age of 20 years.

Treatment for pediatric patients with open physes causes some debate. Nonoperative management of ACL deficiency in adolescents is generally not recommended because the continued instability of the joint leads to intra-articular injury, functional impairment, and joint degeneration.^23-25 A recent systematic review found only 1 study that showed no increase in secondary intra-articular injury when surgery was delayed until skeletal maturity.²⁶ 

Our patient was a 12-year-old boy whose traumatic knee injury with multiple ruptured ligaments healed over the course of 20 months. It is likely that bracing associated with the patient’s second surgery and delayed union of his tibial fracture allowed healing tissue to be protected from excessive stress until it remodeled with sufficient strength. Most would assume that healing would occur early, during the first 6 to 9 months; however, our patient regained his stability between 8 and 13 months. It is possible that the hostile healing environment of the ACL, including the low blood supply, poor response to growth factors, and biomechanical environment, as described previously, played a factor in this delay.^7,9,12,13

It is important to recognize that our patient tore his ACL during a traumatic motorized scooter rollover collision, not the more common noncontact twisting injury. Additionally, given the patient’s knee surgery that was performed 6 months after the initial injury, it is possible that intra-articular scar formation contributed to his healing capacity. While this patient did not undergo arthroscopy to visualize the tear in the ACL, or its reconstitution, recent evidence suggests that the accuracy of MRI in diagnosing pediatric ACL injuries is excellent.^27,28 The diagnostic accuracy with new MRI machines has sensitivity and specificity approaching 100%.²⁹ Additionally, the patient’s subjective and objective improvements argue for a change in anatomy over a change in the quality of his examination.

Conclusion

The goal of ACL reconstruction in adolescents is to provide long-term stability to the knee while minimizing the risk of growth disturbance. This goal was achieved in our patient through the in situ healing of his ACL. Intrinsic reconstitution of a torn ACL is rare, and it is difficult to speculate which patients may have some healing potential. While this patient was an extreme example, his case demonstrated that protection of the knee from undue stress could favorably alter the environment of the knee to allow for healing of ACL tears. Such information could be valuable in managing select pediatric patients with open physes and ACL injuries nonoperatively, sparing them from the risks associated with surgical treatment. While we do not recommend nonoperative treatment for patients with acute tears of the ACL, we believe more investigation into the healing potential of the ACL, and potential pathways to augment this, is warranted.

Fracture blisters are a relatively uncommon complication of high-energy fractures, with an incidence of 2.9%.¹ In the lower extremity, fracture blisters almost always occur distal to the knee.¹ Histologically, the blisters represent an injury to the dermoepidermal junction.² On physical examination, there are tense blood- and/or clear fluid–filled bullae overlying markedly swollen and edematous soft tissue,¹ resembling a second-degree burn.³ Infection may develop after fracture blisters,¹ and this is perhaps the most dreaded complication of total knee arthroplasty (TKA). The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 71-year-old man with end-stage osteoarthritis of the right knee underwent an elective TKA with cemented components (Legion PS; Smith & Nephew). His medical history included venous insufficiency, type 2 diabetes mellitus, chronic obstructive sleep apnea, hypertension, morbid obesity (body mass index, 50), and a previous uneventful left TKA. Tourniquet time was 78 minutes and estimated blood loss was 100 mL. An intra-articular drain was used and was removed on the first postoperative day. After wound closure, a soft splint bandage consisting of 2 to 3 layers of cotton and bias wrap was applied. Deep vein thrombosis (DVT) prophylaxis with enoxaparin 40 mg once daily was started on the first postoperative day.

Upon removal of the surgical dressings on the second postoperative day, the anterior leg was found to have a combination of tense clear fluid– and blood-filled blisters on markedly swollen and erythematous skin. The incision was minimally involved (Figure A). There was diffuse 2+ pitting edema with hyperesthesia in the affected skin distal to the knee. Prior to these findings, the patient had complained of increasing pain in his operative leg, but there was no escalation in analgesic requirements. There was no evidence of compartment syndrome on serial examinations. An ultrasound of the lower extremity was negative for DVT. Plain films did not show iatrogenic fractures. There was no intraoperative vascular injury, and the foot pulses remained unchanged between the time the patient was in the preoperative holding unit, the postanesthesia care unit, and the orthopedic ward. The operative leg was treated with elevation and loosely applied Kerlix roll gauze (Kendall, Covidien), but active blister formation continued for another 2 days. A 10-day prophylactic course of trimethoprim/sulfamethoxazole was initiated on the third postoperative day after the blisters started to rupture. The patient was allowed to bear weight as tolerated, but his physical therapy (PT) course was limited by pain and fear “of losing his leg.” He declined several PT sessions and was hesitant to use continuous passive motion. The patient was discharged to a short-term rehabilitation facility with weekly outpatient follow-up. On the second postoperative week, his fluid-filled blisters completely reepithelialized, but the blood-filled blisters required an additional week for reepithelialization (Figure B). While the patient’s knee was stiff because of limited PT participation, it was not until the second postoperative week when most of the fracture blisters had healed that he was able to resume an intensive knee exercise program, avoiding the need for manipulation under anesthesia.

Discussion

Giordano and colleagues² identified 2 types of fracture blisters: clear fluid– and blood-filled. While both types involved disruption of the dermoepidermal junction, greater disruption and complete absence of dermal epithelial cells was observed in the hemorrhagic type. Clinical follow-up of the patients in the study by Giordano and colleagues² showed that the mean time for reepithelialization was 12 days for fluid-filled blisters and 16 days for blood-filled blisters. These findings are similar to what we observed in our case report. In particular, the fluid-filled blisters healed in 2 weeks, whereas the blood-filled blisters required 3 weeks to heal.

The etiology of the fracture blisters in this patient is likely multifactorial and related to age, obesity, venous insufficiency, and diabetes mellitus. Farage and colleagues⁴ described a series of progressive degenerative changes in the aging skin, including vascular atrophy and degradation of dermal connective tissue, leading to compromised skin competence. The integrity of the dermis can be further reduced in patients with diabetes through glycosylation of collagen fibrils.⁵ Compared with age-matched normal controls, patients with insulin-dependent diabetes have a reduced threshold to suction-induced blister formation.⁶ Obesity is another potential contributing factor, with multiple studies showing significantly impaired venous flow in obese patients.^7,8 Taken together, soft-tissue swelling after surgery in the setting of chronic venous insufficiency and compromised skin due to advanced age and diabetes may lead to markedly elevated interstitial pressure. One mechanism to relieve such abnormally high pressure is the formation of fracture blisters.¹

Surgical risk factors that could have contributed to the complication in this case include the surgical skin preparation solution (ChloraPrep; CareFusion), use of adhesive antimicrobial drape (Ioban, 3M), tourniquet time, dressing choice, and DVT prophylaxis regimen. While the skin preparation solution is an unlikely culprit since the presentation is not consistent with contact dermatitis, inappropriate strapping or removal of the adhesive drape could result in stretch injury of the skin, shearing the dermoepidermal junction and causing tension blisters.⁹ There were no intraoperative complications and the tourniquet time was appropriate (78 minutes). Postoperatively, no compressive or adhesive dressings were used. With regards to DVT prophylaxis, the patient received a single dose of enoxaparin on the first postoperative day. While heparin-induced hemorrhagic blisters have been reported,¹⁰ I do not feel that the use of enoxaparin was a contributing factor. Heparin-induced blisters have been described as systemic blisters,¹⁰ whereas the blisters in this case were confined to the operative extremity. The patient was not taking any nutritional supplements (eg, fish oil, vitamin E) that could have increased his risk of bleeding. Throughout his hospital stay, he was hemodynamically stable and did not require blood transfusion.

Management of fracture blisters is controversial, and there is no consensus on appropriate soft-tissue handling. In this patient, the blisters were left intact. Blister fluid has been shown to be sterile, containing growth factors, opsonins, and activated neutrophils that aid in healing and infection prevention.¹ Giordano and Koval¹¹ found no difference in the outcome of 3 soft-tissue treatment techniques: (1) aspiration of the blister, (2) deroofing of the blister followed by application of a topical antibiotic cream or coverage with nonadherent dressing, or (3) keeping the blister intact and covered with loose dressing or exposed to air. In contrast, Strauss and colleagues¹² found that deroofing the fracture blister to healthy tissue followed by twice-daily application of silver sulfadiazine antibiotic cream promoted reepithelialization and resulted in better cosmetic appearance and higher patient satisfaction. 

The optimal dressing for fracture blisters remains elusive. Madden and colleagues¹³ showed that the use of occlusive nonadherent dressing was associated with significantly faster healing and less pain compared with semiocclusive, antibiotic-impregnated dressings. In another study, Varela and colleagues¹ found no differences in blister healing between patients treated with either (1) dry dressing and casting, (2) Silvadene dressing (King Pharmaceuticals), or (3) whirlpool débridement and Silvadene dressing.

Infection is perhaps the most dreaded complication of fracture blisters after TKA. Varela and colleagues¹ showed that, while the fluid in intact blisters was a sterile transudate, polymicrobial colonization with skin flora often occurred soon after blister rupture and persisted until reepithelialization. Our patient received a 10-day course of prophylactic antibiotics and no superficial or deep infection developed; however, the real contribution of antibiotic prophylaxis to the absence of infection cannot be established based solely on 1 case.

Pain is another concern associated with fracture blisters. Our patient had significant pain that limited his ability to participate in PT, resulting in limited knee range of motion and eventual discharge to a short-term rehabilitation facility. Fortunately, after resolution of the fracture blisters, he was able to participate in an aggressive rehabilitation program. By 6 weeks after surgery, he had significant improvement in his knee motion, avoiding the need for manipulation under anesthesia.

Conclusion

This case represents the first reported fracture blisters after primary TKA. The risk of deep surgical site infection, a devastating complication after TKA, is perhaps the most frightening concern of this rare complication. While the etiology and the management are controversial, there is evidence to recommend prophylactic antibiotics after blister rupture and skin desquamation. The decision to withhold DVT prophylaxis should be based on individual patient risk factors and blister type (blood-filled vs clear fluid–filled). Patients should be encouraged to continue knee exercises during reepithelialization to avoid stiffness.

Fracture blisters are a relatively uncommon complication of high-energy fractures, with an incidence of 2.9%.¹ In the lower extremity, fracture blisters almost always occur distal to the knee.¹ Histologically, the blisters represent an injury to the dermoepidermal junction.² On physical examination, there are tense blood- and/or clear fluid–filled bullae overlying markedly swollen and edematous soft tissue,¹ resembling a second-degree burn.³ Infection may develop after fracture blisters,¹ and this is perhaps the most dreaded complication of total knee arthroplasty (TKA). The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 71-year-old man with end-stage osteoarthritis of the right knee underwent an elective TKA with cemented components (Legion PS; Smith & Nephew). His medical history included venous insufficiency, type 2 diabetes mellitus, chronic obstructive sleep apnea, hypertension, morbid obesity (body mass index, 50), and a previous uneventful left TKA. Tourniquet time was 78 minutes and estimated blood loss was 100 mL. An intra-articular drain was used and was removed on the first postoperative day. After wound closure, a soft splint bandage consisting of 2 to 3 layers of cotton and bias wrap was applied. Deep vein thrombosis (DVT) prophylaxis with enoxaparin 40 mg once daily was started on the first postoperative day.

Upon removal of the surgical dressings on the second postoperative day, the anterior leg was found to have a combination of tense clear fluid– and blood-filled blisters on markedly swollen and erythematous skin. The incision was minimally involved (Figure A). There was diffuse 2+ pitting edema with hyperesthesia in the affected skin distal to the knee. Prior to these findings, the patient had complained of increasing pain in his operative leg, but there was no escalation in analgesic requirements. There was no evidence of compartment syndrome on serial examinations. An ultrasound of the lower extremity was negative for DVT. Plain films did not show iatrogenic fractures. There was no intraoperative vascular injury, and the foot pulses remained unchanged between the time the patient was in the preoperative holding unit, the postanesthesia care unit, and the orthopedic ward. The operative leg was treated with elevation and loosely applied Kerlix roll gauze (Kendall, Covidien), but active blister formation continued for another 2 days. A 10-day prophylactic course of trimethoprim/sulfamethoxazole was initiated on the third postoperative day after the blisters started to rupture. The patient was allowed to bear weight as tolerated, but his physical therapy (PT) course was limited by pain and fear “of losing his leg.” He declined several PT sessions and was hesitant to use continuous passive motion. The patient was discharged to a short-term rehabilitation facility with weekly outpatient follow-up. On the second postoperative week, his fluid-filled blisters completely reepithelialized, but the blood-filled blisters required an additional week for reepithelialization (Figure B). While the patient’s knee was stiff because of limited PT participation, it was not until the second postoperative week when most of the fracture blisters had healed that he was able to resume an intensive knee exercise program, avoiding the need for manipulation under anesthesia.

Discussion

Giordano and colleagues² identified 2 types of fracture blisters: clear fluid– and blood-filled. While both types involved disruption of the dermoepidermal junction, greater disruption and complete absence of dermal epithelial cells was observed in the hemorrhagic type. Clinical follow-up of the patients in the study by Giordano and colleagues² showed that the mean time for reepithelialization was 12 days for fluid-filled blisters and 16 days for blood-filled blisters. These findings are similar to what we observed in our case report. In particular, the fluid-filled blisters healed in 2 weeks, whereas the blood-filled blisters required 3 weeks to heal.

The etiology of the fracture blisters in this patient is likely multifactorial and related to age, obesity, venous insufficiency, and diabetes mellitus. Farage and colleagues⁴ described a series of progressive degenerative changes in the aging skin, including vascular atrophy and degradation of dermal connective tissue, leading to compromised skin competence. The integrity of the dermis can be further reduced in patients with diabetes through glycosylation of collagen fibrils.⁵ Compared with age-matched normal controls, patients with insulin-dependent diabetes have a reduced threshold to suction-induced blister formation.⁶ Obesity is another potential contributing factor, with multiple studies showing significantly impaired venous flow in obese patients.^7,8 Taken together, soft-tissue swelling after surgery in the setting of chronic venous insufficiency and compromised skin due to advanced age and diabetes may lead to markedly elevated interstitial pressure. One mechanism to relieve such abnormally high pressure is the formation of fracture blisters.¹

Surgical risk factors that could have contributed to the complication in this case include the surgical skin preparation solution (ChloraPrep; CareFusion), use of adhesive antimicrobial drape (Ioban, 3M), tourniquet time, dressing choice, and DVT prophylaxis regimen. While the skin preparation solution is an unlikely culprit since the presentation is not consistent with contact dermatitis, inappropriate strapping or removal of the adhesive drape could result in stretch injury of the skin, shearing the dermoepidermal junction and causing tension blisters.⁹ There were no intraoperative complications and the tourniquet time was appropriate (78 minutes). Postoperatively, no compressive or adhesive dressings were used. With regards to DVT prophylaxis, the patient received a single dose of enoxaparin on the first postoperative day. While heparin-induced hemorrhagic blisters have been reported,¹⁰ I do not feel that the use of enoxaparin was a contributing factor. Heparin-induced blisters have been described as systemic blisters,¹⁰ whereas the blisters in this case were confined to the operative extremity. The patient was not taking any nutritional supplements (eg, fish oil, vitamin E) that could have increased his risk of bleeding. Throughout his hospital stay, he was hemodynamically stable and did not require blood transfusion.

Management of fracture blisters is controversial, and there is no consensus on appropriate soft-tissue handling. In this patient, the blisters were left intact. Blister fluid has been shown to be sterile, containing growth factors, opsonins, and activated neutrophils that aid in healing and infection prevention.¹ Giordano and Koval¹¹ found no difference in the outcome of 3 soft-tissue treatment techniques: (1) aspiration of the blister, (2) deroofing of the blister followed by application of a topical antibiotic cream or coverage with nonadherent dressing, or (3) keeping the blister intact and covered with loose dressing or exposed to air. In contrast, Strauss and colleagues¹² found that deroofing the fracture blister to healthy tissue followed by twice-daily application of silver sulfadiazine antibiotic cream promoted reepithelialization and resulted in better cosmetic appearance and higher patient satisfaction. 

The optimal dressing for fracture blisters remains elusive. Madden and colleagues¹³ showed that the use of occlusive nonadherent dressing was associated with significantly faster healing and less pain compared with semiocclusive, antibiotic-impregnated dressings. In another study, Varela and colleagues¹ found no differences in blister healing between patients treated with either (1) dry dressing and casting, (2) Silvadene dressing (King Pharmaceuticals), or (3) whirlpool débridement and Silvadene dressing.

Infection is perhaps the most dreaded complication of fracture blisters after TKA. Varela and colleagues¹ showed that, while the fluid in intact blisters was a sterile transudate, polymicrobial colonization with skin flora often occurred soon after blister rupture and persisted until reepithelialization. Our patient received a 10-day course of prophylactic antibiotics and no superficial or deep infection developed; however, the real contribution of antibiotic prophylaxis to the absence of infection cannot be established based solely on 1 case.

Pain is another concern associated with fracture blisters. Our patient had significant pain that limited his ability to participate in PT, resulting in limited knee range of motion and eventual discharge to a short-term rehabilitation facility. Fortunately, after resolution of the fracture blisters, he was able to participate in an aggressive rehabilitation program. By 6 weeks after surgery, he had significant improvement in his knee motion, avoiding the need for manipulation under anesthesia.

Conclusion

This case represents the first reported fracture blisters after primary TKA. The risk of deep surgical site infection, a devastating complication after TKA, is perhaps the most frightening concern of this rare complication. While the etiology and the management are controversial, there is evidence to recommend prophylactic antibiotics after blister rupture and skin desquamation. The decision to withhold DVT prophylaxis should be based on individual patient risk factors and blister type (blood-filled vs clear fluid–filled). Patients should be encouraged to continue knee exercises during reepithelialization to avoid stiffness.

Fracture blisters are a relatively uncommon complication of high-energy fractures, with an incidence of 2.9%.¹ In the lower extremity, fracture blisters almost always occur distal to the knee.¹ Histologically, the blisters represent an injury to the dermoepidermal junction.² On physical examination, there are tense blood- and/or clear fluid–filled bullae overlying markedly swollen and edematous soft tissue,¹ resembling a second-degree burn.³ Infection may develop after fracture blisters,¹ and this is perhaps the most dreaded complication of total knee arthroplasty (TKA). The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 71-year-old man with end-stage osteoarthritis of the right knee underwent an elective TKA with cemented components (Legion PS; Smith & Nephew). His medical history included venous insufficiency, type 2 diabetes mellitus, chronic obstructive sleep apnea, hypertension, morbid obesity (body mass index, 50), and a previous uneventful left TKA. Tourniquet time was 78 minutes and estimated blood loss was 100 mL. An intra-articular drain was used and was removed on the first postoperative day. After wound closure, a soft splint bandage consisting of 2 to 3 layers of cotton and bias wrap was applied. Deep vein thrombosis (DVT) prophylaxis with enoxaparin 40 mg once daily was started on the first postoperative day.

Upon removal of the surgical dressings on the second postoperative day, the anterior leg was found to have a combination of tense clear fluid– and blood-filled blisters on markedly swollen and erythematous skin. The incision was minimally involved (Figure A). There was diffuse 2+ pitting edema with hyperesthesia in the affected skin distal to the knee. Prior to these findings, the patient had complained of increasing pain in his operative leg, but there was no escalation in analgesic requirements. There was no evidence of compartment syndrome on serial examinations. An ultrasound of the lower extremity was negative for DVT. Plain films did not show iatrogenic fractures. There was no intraoperative vascular injury, and the foot pulses remained unchanged between the time the patient was in the preoperative holding unit, the postanesthesia care unit, and the orthopedic ward. The operative leg was treated with elevation and loosely applied Kerlix roll gauze (Kendall, Covidien), but active blister formation continued for another 2 days. A 10-day prophylactic course of trimethoprim/sulfamethoxazole was initiated on the third postoperative day after the blisters started to rupture. The patient was allowed to bear weight as tolerated, but his physical therapy (PT) course was limited by pain and fear “of losing his leg.” He declined several PT sessions and was hesitant to use continuous passive motion. The patient was discharged to a short-term rehabilitation facility with weekly outpatient follow-up. On the second postoperative week, his fluid-filled blisters completely reepithelialized, but the blood-filled blisters required an additional week for reepithelialization (Figure B). While the patient’s knee was stiff because of limited PT participation, it was not until the second postoperative week when most of the fracture blisters had healed that he was able to resume an intensive knee exercise program, avoiding the need for manipulation under anesthesia.

Discussion

Giordano and colleagues² identified 2 types of fracture blisters: clear fluid– and blood-filled. While both types involved disruption of the dermoepidermal junction, greater disruption and complete absence of dermal epithelial cells was observed in the hemorrhagic type. Clinical follow-up of the patients in the study by Giordano and colleagues² showed that the mean time for reepithelialization was 12 days for fluid-filled blisters and 16 days for blood-filled blisters. These findings are similar to what we observed in our case report. In particular, the fluid-filled blisters healed in 2 weeks, whereas the blood-filled blisters required 3 weeks to heal.

The etiology of the fracture blisters in this patient is likely multifactorial and related to age, obesity, venous insufficiency, and diabetes mellitus. Farage and colleagues⁴ described a series of progressive degenerative changes in the aging skin, including vascular atrophy and degradation of dermal connective tissue, leading to compromised skin competence. The integrity of the dermis can be further reduced in patients with diabetes through glycosylation of collagen fibrils.⁵ Compared with age-matched normal controls, patients with insulin-dependent diabetes have a reduced threshold to suction-induced blister formation.⁶ Obesity is another potential contributing factor, with multiple studies showing significantly impaired venous flow in obese patients.^7,8 Taken together, soft-tissue swelling after surgery in the setting of chronic venous insufficiency and compromised skin due to advanced age and diabetes may lead to markedly elevated interstitial pressure. One mechanism to relieve such abnormally high pressure is the formation of fracture blisters.¹

Surgical risk factors that could have contributed to the complication in this case include the surgical skin preparation solution (ChloraPrep; CareFusion), use of adhesive antimicrobial drape (Ioban, 3M), tourniquet time, dressing choice, and DVT prophylaxis regimen. While the skin preparation solution is an unlikely culprit since the presentation is not consistent with contact dermatitis, inappropriate strapping or removal of the adhesive drape could result in stretch injury of the skin, shearing the dermoepidermal junction and causing tension blisters.⁹ There were no intraoperative complications and the tourniquet time was appropriate (78 minutes). Postoperatively, no compressive or adhesive dressings were used. With regards to DVT prophylaxis, the patient received a single dose of enoxaparin on the first postoperative day. While heparin-induced hemorrhagic blisters have been reported,¹⁰ I do not feel that the use of enoxaparin was a contributing factor. Heparin-induced blisters have been described as systemic blisters,¹⁰ whereas the blisters in this case were confined to the operative extremity. The patient was not taking any nutritional supplements (eg, fish oil, vitamin E) that could have increased his risk of bleeding. Throughout his hospital stay, he was hemodynamically stable and did not require blood transfusion.

Management of fracture blisters is controversial, and there is no consensus on appropriate soft-tissue handling. In this patient, the blisters were left intact. Blister fluid has been shown to be sterile, containing growth factors, opsonins, and activated neutrophils that aid in healing and infection prevention.¹ Giordano and Koval¹¹ found no difference in the outcome of 3 soft-tissue treatment techniques: (1) aspiration of the blister, (2) deroofing of the blister followed by application of a topical antibiotic cream or coverage with nonadherent dressing, or (3) keeping the blister intact and covered with loose dressing or exposed to air. In contrast, Strauss and colleagues¹² found that deroofing the fracture blister to healthy tissue followed by twice-daily application of silver sulfadiazine antibiotic cream promoted reepithelialization and resulted in better cosmetic appearance and higher patient satisfaction. 

The optimal dressing for fracture blisters remains elusive. Madden and colleagues¹³ showed that the use of occlusive nonadherent dressing was associated with significantly faster healing and less pain compared with semiocclusive, antibiotic-impregnated dressings. In another study, Varela and colleagues¹ found no differences in blister healing between patients treated with either (1) dry dressing and casting, (2) Silvadene dressing (King Pharmaceuticals), or (3) whirlpool débridement and Silvadene dressing.

Infection is perhaps the most dreaded complication of fracture blisters after TKA. Varela and colleagues¹ showed that, while the fluid in intact blisters was a sterile transudate, polymicrobial colonization with skin flora often occurred soon after blister rupture and persisted until reepithelialization. Our patient received a 10-day course of prophylactic antibiotics and no superficial or deep infection developed; however, the real contribution of antibiotic prophylaxis to the absence of infection cannot be established based solely on 1 case.

Pain is another concern associated with fracture blisters. Our patient had significant pain that limited his ability to participate in PT, resulting in limited knee range of motion and eventual discharge to a short-term rehabilitation facility. Fortunately, after resolution of the fracture blisters, he was able to participate in an aggressive rehabilitation program. By 6 weeks after surgery, he had significant improvement in his knee motion, avoiding the need for manipulation under anesthesia.

Conclusion

This case represents the first reported fracture blisters after primary TKA. The risk of deep surgical site infection, a devastating complication after TKA, is perhaps the most frightening concern of this rare complication. While the etiology and the management are controversial, there is evidence to recommend prophylactic antibiotics after blister rupture and skin desquamation. The decision to withhold DVT prophylaxis should be based on individual patient risk factors and blister type (blood-filled vs clear fluid–filled). Patients should be encouraged to continue knee exercises during reepithelialization to avoid stiffness.

Synovial chondromatosis (SCM) is a relatively rare benign lesion of the synovium.¹ Its pathogenesis has been thought to be a chondral metaplasia of the subintimal layer of the intra- or extra-articular synovium.² However, evidence supporting a neoplastic cause of the disease is emerging.³ When intra-articular, any joint can be affected, though large joints are more prone to the disease; the knee, hip, and elbow are the most common locations.⁴ The synovial layer of tendons or bursae can be the origin of extra-articular SCM.⁵

Synovial chondrosarcoma (SCS), an even rarer pathology, can be caused by malignant transformation of SCM or can appear de novo on a synovial background.⁶ Histologic differentiation from SCM might be difficult because of the high incidence of hypercellularity, cellular atypia, and binucleated cells.⁶ Some features, such as presence of a very large mass or erosion of the surrounding bones, have been indicated as possible signs of malignancy.³ An unusual presentation of SCM, giant solitary synovial chondromatosis (GSSCM), can be hard to distinguish from SCS because of the large volume and possible aggressive radiologic findings.⁷ Some histologic features, such as presence of necrosis and mitotic cells, have been suggested as distinctive criteria for malignancy.⁸

In this article, we present a case of benign GSSCM with a histologic feature that has not been considered typical for benign SCM. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

An 18-year-old woman presented with a large mass over the right hip. The mass had been growing slowly for 2 years. One year before presentation, a radiograph showed a large hip mass with fluffy calcification (Figure 1), and magnetic resonance imaging (MRI) showed a large nonhomogeneous mass anterior to the hip capsule and extending into the hip joint back to the posterior part of the joint (Figures 2A, 2B). Open incisional biopsy was performed in a local hospital at the time, and the histologic analysis revealed presence of atypical binucleated cells and pleomorphism, in addition to some mitotic activity (0 to 1 per high-power field) (Figure 3). These findings suggested malignancy. The patient declined surgery up until the time she presented to our hospital, 1 year later.

Clinical examination findings on admission to our hospital were striking. The patient had a large mass in the groin region. It was fairly tender and firm to palpation, immobile, and close to the skin. Hip motion was mildly painful but obviously restricted.

The mass was restaged. New radiographs and MRI did not show any significant changes since the previous year, computed tomography (CT) did not show any bone erosion (Figure 4), and chest radiograph, CT, and whole-body bone scan did not demonstrate any signs of metastasis.

Given the clinical presentation and previous histopathologic findings, a diagnosis of GSSCM with possible malignant transformation was made. The patient was scheduled for surgery. During surgery, the tumor was exposed through the Smith-Petersen approach. The mass was extruding under the fascia between the femoral neurovascular bundle medially and iliopsoas muscle laterally. There was no adhesion of the surrounding structures, including the femoral neurovascular bundle, to the mass. The muscle was sitting on the anterolateral surface of the mass, which was considered located in the iliopsoas bursa but extending to the joint. In the vertical plane, the mass extended down to the subtrochanteric area. The entire solid extra-articular mass was excised en bloc, and hip capsulotomy was performed inferior to the area of emergence of the mass. The joint was occupied by a single solid cartilaginous mass molding around the femoral neck, filling the piriformis fossa and propagating to the posterior joint space. Obtaining enough exposure to the back of the joint required surgical hip dislocation. The visualized acetabular fossa revealed chondral fragments, which were excised. Bone erosion or significant osteoarthritis was not detected in any part of the joint. A nearly total synovectomy was performed, leaving the ascending retinacular vessels intact. Meticulous technique was used to avoid contaminating the extra-articular tissues. The wound was closed in the routine way after hip relocation.

The 16×9.5×9-cm mass (Figure 5A) had a conglomerated internal structure (Figure 5B). Multiple specimens from the intra- and extra-articular portions of the mass were sent for histopathologic analysis, which revealed clusters of mature chondrocytes arranged in a lobular pattern and separated by thin fibrous bands. Areas of calcification and ossification were appreciated as well (Figures 6A-6C). No necrosis, mitosis, or bone permeation was detected. These findings were compatible with typical SCM. Given these pathologic findings and the lack of clinical deterioration over the previous year, a diagnosis of GSSCM with extension along the iliopsoas and obturator externus bursae was made. The already-performed marginal excision was deemed sufficient treatment. At most recent follow-up, 38 months after surgery, the patient was pain-free and had good hip range of motion and no indication of recurrence.

Discussion

SCM is a benign disorder emerging from the synovium as a result of proliferative changes in the synovial membrane of the joints, tendon sheaths, or bursae, leading to the formation of numerous cartilaginous nodules, usually a few millimeters in diameter.⁸ In a rare presentation of the disease, the nodules may coalesce to form a large mass, or a single cartilaginous nodule may enlarge to form a mass. Edeiken and colleagues⁷ named this previously unrecognized SCM feature as GSSCM when there was a major single mass larger than 1 cm in diameter. There have been other SCM cases with multiple giant masses.^9,10 In the English-language literature, we found 15 GSSCM cases, which include the first reported, by Edeiken and colleagues⁷ (Table). However, earlier SCM cases would be reclassified GSSCM according to their definition.¹¹

The present case brings the total to 16. Nine of the 16 patients were male. Mean age at presentation was 41 years (range, 10-80 years). The knee was the most common GSSCM site (6 cases), followed by the temporomandibular and hip joints (3 each). Regarding gross pathology, 10 lesions were solid, and 6 (including the present one) were formed by conglomeration of the chondromatosis nodules. Lesions varied in size (16-200 mm), and 2 were primarily extra-articular (foot). One common issue with most of the cases was the initial diagnosis of chondrosarcoma. The exact surgical technique used was described for 6 cases (cases 11-16); the technique was marginal excision. In no case was recurrence 14 to 60 months after surgery reported.

This chondroproliferative process is potentially a diagnostic challenge, as distinguishing it from a chondrosarcoma, a more common lesion, could be difficult based on clinical and imaging findings, and, as is true for other chondral lesions, even histologic differentiation of the conditions might not be conclusive.^12,13 Confusion in diagnosis was almost universal in this series of patients.

One important differentiating feature of benign and malignant skeletal lesions is the time course of the disease. Malignant tumors are expected to demonstrate rapid enlargement and local or systemic spread. Unfortunately, often SCS cannot be distinguished by this characteristic, as grade I or II chondrosarcoma is usually a slow-growing tumor and does not metastasize early.¹⁴ Although lack of recurrence is assuring, recurrence is not necessarily a sign of malignancy, as a considerable percentage of benign chondromatosis lesions recur.⁸

Radiologic differentiation between SCM and SCS is another challenge. Although bone erosion caused by a lesion not originating from bone is usually considered a sign of malignancy, GSSCM was reported as causing bone erosion in 5 of the 16 cases in our literature review.^7,15 Our patient did not experience any bone erosion. However, lack of bone erosion is not a reliable criterion for excluding SCS, and bone erosion was noted in only 3 of the 9 SCS cases in the series reported by Bertoni and colleagues.⁶ Moreover, tumor size and propagation of tumor to surrounding tissue could be surprising in GSSCM. Large size (up to 20 cm) and extra-articular spread of a lesion originating in a joint are common findings.^6,16 Our case was an obvious extension of a hip GSSCM to the iliopsoas and obturator externus bursa, which is the most common pattern of extracapsular spread of hip SCM.¹⁷ An interesting feature of the present case, however, was the relatively superficial location of the mass immediately under the fascia.

Calcified matrix is key in diagnosing a chondral lesion on imaging studies, but, in some cases, SCM does not demonstrate any radiographically detectable calcification at time of diagnosis.¹⁸ However, all the GSSCM cases reported to date had obvious calcified matrix.

The hypercellularity, cellular atypia, binucleated cells, and pleomorphism in the histologic examination of the present case are not features of malignancy in SCM.⁸ On the contrary, several other characteristics, including qualitative differences in the arrangement of chondrocytes (sheets rather than clusters), myxoid matrix, hypercellularity with crowding and spindling of the nuclei at the periphery, necrosis, and, most important, permeation of the trabecular bone with the filling up of marrow spaces, have been assumed to be indicative of malignancy.⁸ Furthermore, Davis and colleagues⁸ found no mitotic activity in the histopathologic investigation of 53 SCM cases. Even in 3 cases that developed malignant transformation to SCS, mitosis was not found in the initial biopsy specimens before transformation. This was compatible with the common opinion that SCM is not a neoplastic, but a metaplastic, process. Histopathologic data were available for only 8 of the previous 15 GSSCM cases. There were no reports of mitosis, and necrosis was found in only 1 case.¹⁶ In our patient’s case, however, the first biopsy did show remarkable mitotic activity. This was not the case for the second biopsy, when mature chondrocytes associated with marked calcification and ossification were prominent features (Figures 6A, 6B). We presume that, within a limited period during earlier stages of tissue maturation in SCM, mitotic activity might be a possible finding. Of note, none of the other aforementioned histologic criteria for malignancy was seen in the first or second biopsy in the present case (Figures 3, 6C).

The original idea that SCM originates from a metaplasia in the subintimal layer of the synovium, where the synovium is in direct contact with the articular cartilage, has been challenged. The high incidence of hypercellularity, binucleated cells, and cellular atypia was always an argument against a metaplastic origin for the disease. Evidence of clonal chromosomal changes, like translocation of chromosome 1218 and chromosome 5 and 6 abnormalities,^19,20 in addition to other alterations,^19,21 provide some evidence supporting a neoplastic rather than a metaplastic origin for SCM. Given the presence of mitosis in the present case, the lack of mitotic activity in SCM, as stated by other authors,²² is not a universal feature and cannot be used as an argument against a neoplastic origin for SCM.

Although mitotic activity is uncommon in SCM, the present case illustrates the possible presence of mitotic activity in GSSCM. The simple presence of mitotic activity, a common finding in some other chondral tumors,23,24 does not preclude the diagnosis of benign SCM, as suggested before,8 and correlation of the clinical and radiologic manifestations with histopathologic findings is crucial for a correct diagnosis.

Synovial chondromatosis (SCM) is a relatively rare benign lesion of the synovium.¹ Its pathogenesis has been thought to be a chondral metaplasia of the subintimal layer of the intra- or extra-articular synovium.² However, evidence supporting a neoplastic cause of the disease is emerging.³ When intra-articular, any joint can be affected, though large joints are more prone to the disease; the knee, hip, and elbow are the most common locations.⁴ The synovial layer of tendons or bursae can be the origin of extra-articular SCM.⁵

Synovial chondrosarcoma (SCS), an even rarer pathology, can be caused by malignant transformation of SCM or can appear de novo on a synovial background.⁶ Histologic differentiation from SCM might be difficult because of the high incidence of hypercellularity, cellular atypia, and binucleated cells.⁶ Some features, such as presence of a very large mass or erosion of the surrounding bones, have been indicated as possible signs of malignancy.³ An unusual presentation of SCM, giant solitary synovial chondromatosis (GSSCM), can be hard to distinguish from SCS because of the large volume and possible aggressive radiologic findings.⁷ Some histologic features, such as presence of necrosis and mitotic cells, have been suggested as distinctive criteria for malignancy.⁸

In this article, we present a case of benign GSSCM with a histologic feature that has not been considered typical for benign SCM. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

An 18-year-old woman presented with a large mass over the right hip. The mass had been growing slowly for 2 years. One year before presentation, a radiograph showed a large hip mass with fluffy calcification (Figure 1), and magnetic resonance imaging (MRI) showed a large nonhomogeneous mass anterior to the hip capsule and extending into the hip joint back to the posterior part of the joint (Figures 2A, 2B). Open incisional biopsy was performed in a local hospital at the time, and the histologic analysis revealed presence of atypical binucleated cells and pleomorphism, in addition to some mitotic activity (0 to 1 per high-power field) (Figure 3). These findings suggested malignancy. The patient declined surgery up until the time she presented to our hospital, 1 year later.

Clinical examination findings on admission to our hospital were striking. The patient had a large mass in the groin region. It was fairly tender and firm to palpation, immobile, and close to the skin. Hip motion was mildly painful but obviously restricted.

The mass was restaged. New radiographs and MRI did not show any significant changes since the previous year, computed tomography (CT) did not show any bone erosion (Figure 4), and chest radiograph, CT, and whole-body bone scan did not demonstrate any signs of metastasis.

Given the clinical presentation and previous histopathologic findings, a diagnosis of GSSCM with possible malignant transformation was made. The patient was scheduled for surgery. During surgery, the tumor was exposed through the Smith-Petersen approach. The mass was extruding under the fascia between the femoral neurovascular bundle medially and iliopsoas muscle laterally. There was no adhesion of the surrounding structures, including the femoral neurovascular bundle, to the mass. The muscle was sitting on the anterolateral surface of the mass, which was considered located in the iliopsoas bursa but extending to the joint. In the vertical plane, the mass extended down to the subtrochanteric area. The entire solid extra-articular mass was excised en bloc, and hip capsulotomy was performed inferior to the area of emergence of the mass. The joint was occupied by a single solid cartilaginous mass molding around the femoral neck, filling the piriformis fossa and propagating to the posterior joint space. Obtaining enough exposure to the back of the joint required surgical hip dislocation. The visualized acetabular fossa revealed chondral fragments, which were excised. Bone erosion or significant osteoarthritis was not detected in any part of the joint. A nearly total synovectomy was performed, leaving the ascending retinacular vessels intact. Meticulous technique was used to avoid contaminating the extra-articular tissues. The wound was closed in the routine way after hip relocation.

The 16×9.5×9-cm mass (Figure 5A) had a conglomerated internal structure (Figure 5B). Multiple specimens from the intra- and extra-articular portions of the mass were sent for histopathologic analysis, which revealed clusters of mature chondrocytes arranged in a lobular pattern and separated by thin fibrous bands. Areas of calcification and ossification were appreciated as well (Figures 6A-6C). No necrosis, mitosis, or bone permeation was detected. These findings were compatible with typical SCM. Given these pathologic findings and the lack of clinical deterioration over the previous year, a diagnosis of GSSCM with extension along the iliopsoas and obturator externus bursae was made. The already-performed marginal excision was deemed sufficient treatment. At most recent follow-up, 38 months after surgery, the patient was pain-free and had good hip range of motion and no indication of recurrence.

Discussion

SCM is a benign disorder emerging from the synovium as a result of proliferative changes in the synovial membrane of the joints, tendon sheaths, or bursae, leading to the formation of numerous cartilaginous nodules, usually a few millimeters in diameter.⁸ In a rare presentation of the disease, the nodules may coalesce to form a large mass, or a single cartilaginous nodule may enlarge to form a mass. Edeiken and colleagues⁷ named this previously unrecognized SCM feature as GSSCM when there was a major single mass larger than 1 cm in diameter. There have been other SCM cases with multiple giant masses.^9,10 In the English-language literature, we found 15 GSSCM cases, which include the first reported, by Edeiken and colleagues⁷ (Table). However, earlier SCM cases would be reclassified GSSCM according to their definition.¹¹

The present case brings the total to 16. Nine of the 16 patients were male. Mean age at presentation was 41 years (range, 10-80 years). The knee was the most common GSSCM site (6 cases), followed by the temporomandibular and hip joints (3 each). Regarding gross pathology, 10 lesions were solid, and 6 (including the present one) were formed by conglomeration of the chondromatosis nodules. Lesions varied in size (16-200 mm), and 2 were primarily extra-articular (foot). One common issue with most of the cases was the initial diagnosis of chondrosarcoma. The exact surgical technique used was described for 6 cases (cases 11-16); the technique was marginal excision. In no case was recurrence 14 to 60 months after surgery reported.

This chondroproliferative process is potentially a diagnostic challenge, as distinguishing it from a chondrosarcoma, a more common lesion, could be difficult based on clinical and imaging findings, and, as is true for other chondral lesions, even histologic differentiation of the conditions might not be conclusive.^12,13 Confusion in diagnosis was almost universal in this series of patients.

One important differentiating feature of benign and malignant skeletal lesions is the time course of the disease. Malignant tumors are expected to demonstrate rapid enlargement and local or systemic spread. Unfortunately, often SCS cannot be distinguished by this characteristic, as grade I or II chondrosarcoma is usually a slow-growing tumor and does not metastasize early.¹⁴ Although lack of recurrence is assuring, recurrence is not necessarily a sign of malignancy, as a considerable percentage of benign chondromatosis lesions recur.⁸

Radiologic differentiation between SCM and SCS is another challenge. Although bone erosion caused by a lesion not originating from bone is usually considered a sign of malignancy, GSSCM was reported as causing bone erosion in 5 of the 16 cases in our literature review.^7,15 Our patient did not experience any bone erosion. However, lack of bone erosion is not a reliable criterion for excluding SCS, and bone erosion was noted in only 3 of the 9 SCS cases in the series reported by Bertoni and colleagues.⁶ Moreover, tumor size and propagation of tumor to surrounding tissue could be surprising in GSSCM. Large size (up to 20 cm) and extra-articular spread of a lesion originating in a joint are common findings.^6,16 Our case was an obvious extension of a hip GSSCM to the iliopsoas and obturator externus bursa, which is the most common pattern of extracapsular spread of hip SCM.¹⁷ An interesting feature of the present case, however, was the relatively superficial location of the mass immediately under the fascia.

Calcified matrix is key in diagnosing a chondral lesion on imaging studies, but, in some cases, SCM does not demonstrate any radiographically detectable calcification at time of diagnosis.¹⁸ However, all the GSSCM cases reported to date had obvious calcified matrix.

The hypercellularity, cellular atypia, binucleated cells, and pleomorphism in the histologic examination of the present case are not features of malignancy in SCM.⁸ On the contrary, several other characteristics, including qualitative differences in the arrangement of chondrocytes (sheets rather than clusters), myxoid matrix, hypercellularity with crowding and spindling of the nuclei at the periphery, necrosis, and, most important, permeation of the trabecular bone with the filling up of marrow spaces, have been assumed to be indicative of malignancy.⁸ Furthermore, Davis and colleagues⁸ found no mitotic activity in the histopathologic investigation of 53 SCM cases. Even in 3 cases that developed malignant transformation to SCS, mitosis was not found in the initial biopsy specimens before transformation. This was compatible with the common opinion that SCM is not a neoplastic, but a metaplastic, process. Histopathologic data were available for only 8 of the previous 15 GSSCM cases. There were no reports of mitosis, and necrosis was found in only 1 case.¹⁶ In our patient’s case, however, the first biopsy did show remarkable mitotic activity. This was not the case for the second biopsy, when mature chondrocytes associated with marked calcification and ossification were prominent features (Figures 6A, 6B). We presume that, within a limited period during earlier stages of tissue maturation in SCM, mitotic activity might be a possible finding. Of note, none of the other aforementioned histologic criteria for malignancy was seen in the first or second biopsy in the present case (Figures 3, 6C).

The original idea that SCM originates from a metaplasia in the subintimal layer of the synovium, where the synovium is in direct contact with the articular cartilage, has been challenged. The high incidence of hypercellularity, binucleated cells, and cellular atypia was always an argument against a metaplastic origin for the disease. Evidence of clonal chromosomal changes, like translocation of chromosome 1218 and chromosome 5 and 6 abnormalities,^19,20 in addition to other alterations,^19,21 provide some evidence supporting a neoplastic rather than a metaplastic origin for SCM. Given the presence of mitosis in the present case, the lack of mitotic activity in SCM, as stated by other authors,²² is not a universal feature and cannot be used as an argument against a neoplastic origin for SCM.

Although mitotic activity is uncommon in SCM, the present case illustrates the possible presence of mitotic activity in GSSCM. The simple presence of mitotic activity, a common finding in some other chondral tumors,23,24 does not preclude the diagnosis of benign SCM, as suggested before,8 and correlation of the clinical and radiologic manifestations with histopathologic findings is crucial for a correct diagnosis.

Synovial chondromatosis (SCM) is a relatively rare benign lesion of the synovium.¹ Its pathogenesis has been thought to be a chondral metaplasia of the subintimal layer of the intra- or extra-articular synovium.² However, evidence supporting a neoplastic cause of the disease is emerging.³ When intra-articular, any joint can be affected, though large joints are more prone to the disease; the knee, hip, and elbow are the most common locations.⁴ The synovial layer of tendons or bursae can be the origin of extra-articular SCM.⁵

Synovial chondrosarcoma (SCS), an even rarer pathology, can be caused by malignant transformation of SCM or can appear de novo on a synovial background.⁶ Histologic differentiation from SCM might be difficult because of the high incidence of hypercellularity, cellular atypia, and binucleated cells.⁶ Some features, such as presence of a very large mass or erosion of the surrounding bones, have been indicated as possible signs of malignancy.³ An unusual presentation of SCM, giant solitary synovial chondromatosis (GSSCM), can be hard to distinguish from SCS because of the large volume and possible aggressive radiologic findings.⁷ Some histologic features, such as presence of necrosis and mitotic cells, have been suggested as distinctive criteria for malignancy.⁸

In this article, we present a case of benign GSSCM with a histologic feature that has not been considered typical for benign SCM. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

An 18-year-old woman presented with a large mass over the right hip. The mass had been growing slowly for 2 years. One year before presentation, a radiograph showed a large hip mass with fluffy calcification (Figure 1), and magnetic resonance imaging (MRI) showed a large nonhomogeneous mass anterior to the hip capsule and extending into the hip joint back to the posterior part of the joint (Figures 2A, 2B). Open incisional biopsy was performed in a local hospital at the time, and the histologic analysis revealed presence of atypical binucleated cells and pleomorphism, in addition to some mitotic activity (0 to 1 per high-power field) (Figure 3). These findings suggested malignancy. The patient declined surgery up until the time she presented to our hospital, 1 year later.

Clinical examination findings on admission to our hospital were striking. The patient had a large mass in the groin region. It was fairly tender and firm to palpation, immobile, and close to the skin. Hip motion was mildly painful but obviously restricted.

The mass was restaged. New radiographs and MRI did not show any significant changes since the previous year, computed tomography (CT) did not show any bone erosion (Figure 4), and chest radiograph, CT, and whole-body bone scan did not demonstrate any signs of metastasis.

Given the clinical presentation and previous histopathologic findings, a diagnosis of GSSCM with possible malignant transformation was made. The patient was scheduled for surgery. During surgery, the tumor was exposed through the Smith-Petersen approach. The mass was extruding under the fascia between the femoral neurovascular bundle medially and iliopsoas muscle laterally. There was no adhesion of the surrounding structures, including the femoral neurovascular bundle, to the mass. The muscle was sitting on the anterolateral surface of the mass, which was considered located in the iliopsoas bursa but extending to the joint. In the vertical plane, the mass extended down to the subtrochanteric area. The entire solid extra-articular mass was excised en bloc, and hip capsulotomy was performed inferior to the area of emergence of the mass. The joint was occupied by a single solid cartilaginous mass molding around the femoral neck, filling the piriformis fossa and propagating to the posterior joint space. Obtaining enough exposure to the back of the joint required surgical hip dislocation. The visualized acetabular fossa revealed chondral fragments, which were excised. Bone erosion or significant osteoarthritis was not detected in any part of the joint. A nearly total synovectomy was performed, leaving the ascending retinacular vessels intact. Meticulous technique was used to avoid contaminating the extra-articular tissues. The wound was closed in the routine way after hip relocation.

The 16×9.5×9-cm mass (Figure 5A) had a conglomerated internal structure (Figure 5B). Multiple specimens from the intra- and extra-articular portions of the mass were sent for histopathologic analysis, which revealed clusters of mature chondrocytes arranged in a lobular pattern and separated by thin fibrous bands. Areas of calcification and ossification were appreciated as well (Figures 6A-6C). No necrosis, mitosis, or bone permeation was detected. These findings were compatible with typical SCM. Given these pathologic findings and the lack of clinical deterioration over the previous year, a diagnosis of GSSCM with extension along the iliopsoas and obturator externus bursae was made. The already-performed marginal excision was deemed sufficient treatment. At most recent follow-up, 38 months after surgery, the patient was pain-free and had good hip range of motion and no indication of recurrence.

Discussion

SCM is a benign disorder emerging from the synovium as a result of proliferative changes in the synovial membrane of the joints, tendon sheaths, or bursae, leading to the formation of numerous cartilaginous nodules, usually a few millimeters in diameter.⁸ In a rare presentation of the disease, the nodules may coalesce to form a large mass, or a single cartilaginous nodule may enlarge to form a mass. Edeiken and colleagues⁷ named this previously unrecognized SCM feature as GSSCM when there was a major single mass larger than 1 cm in diameter. There have been other SCM cases with multiple giant masses.^9,10 In the English-language literature, we found 15 GSSCM cases, which include the first reported, by Edeiken and colleagues⁷ (Table). However, earlier SCM cases would be reclassified GSSCM according to their definition.¹¹

The present case brings the total to 16. Nine of the 16 patients were male. Mean age at presentation was 41 years (range, 10-80 years). The knee was the most common GSSCM site (6 cases), followed by the temporomandibular and hip joints (3 each). Regarding gross pathology, 10 lesions were solid, and 6 (including the present one) were formed by conglomeration of the chondromatosis nodules. Lesions varied in size (16-200 mm), and 2 were primarily extra-articular (foot). One common issue with most of the cases was the initial diagnosis of chondrosarcoma. The exact surgical technique used was described for 6 cases (cases 11-16); the technique was marginal excision. In no case was recurrence 14 to 60 months after surgery reported.

This chondroproliferative process is potentially a diagnostic challenge, as distinguishing it from a chondrosarcoma, a more common lesion, could be difficult based on clinical and imaging findings, and, as is true for other chondral lesions, even histologic differentiation of the conditions might not be conclusive.^12,13 Confusion in diagnosis was almost universal in this series of patients.

One important differentiating feature of benign and malignant skeletal lesions is the time course of the disease. Malignant tumors are expected to demonstrate rapid enlargement and local or systemic spread. Unfortunately, often SCS cannot be distinguished by this characteristic, as grade I or II chondrosarcoma is usually a slow-growing tumor and does not metastasize early.¹⁴ Although lack of recurrence is assuring, recurrence is not necessarily a sign of malignancy, as a considerable percentage of benign chondromatosis lesions recur.⁸

Radiologic differentiation between SCM and SCS is another challenge. Although bone erosion caused by a lesion not originating from bone is usually considered a sign of malignancy, GSSCM was reported as causing bone erosion in 5 of the 16 cases in our literature review.^7,15 Our patient did not experience any bone erosion. However, lack of bone erosion is not a reliable criterion for excluding SCS, and bone erosion was noted in only 3 of the 9 SCS cases in the series reported by Bertoni and colleagues.⁶ Moreover, tumor size and propagation of tumor to surrounding tissue could be surprising in GSSCM. Large size (up to 20 cm) and extra-articular spread of a lesion originating in a joint are common findings.^6,16 Our case was an obvious extension of a hip GSSCM to the iliopsoas and obturator externus bursa, which is the most common pattern of extracapsular spread of hip SCM.¹⁷ An interesting feature of the present case, however, was the relatively superficial location of the mass immediately under the fascia.

Calcified matrix is key in diagnosing a chondral lesion on imaging studies, but, in some cases, SCM does not demonstrate any radiographically detectable calcification at time of diagnosis.¹⁸ However, all the GSSCM cases reported to date had obvious calcified matrix.

The hypercellularity, cellular atypia, binucleated cells, and pleomorphism in the histologic examination of the present case are not features of malignancy in SCM.⁸ On the contrary, several other characteristics, including qualitative differences in the arrangement of chondrocytes (sheets rather than clusters), myxoid matrix, hypercellularity with crowding and spindling of the nuclei at the periphery, necrosis, and, most important, permeation of the trabecular bone with the filling up of marrow spaces, have been assumed to be indicative of malignancy.⁸ Furthermore, Davis and colleagues⁸ found no mitotic activity in the histopathologic investigation of 53 SCM cases. Even in 3 cases that developed malignant transformation to SCS, mitosis was not found in the initial biopsy specimens before transformation. This was compatible with the common opinion that SCM is not a neoplastic, but a metaplastic, process. Histopathologic data were available for only 8 of the previous 15 GSSCM cases. There were no reports of mitosis, and necrosis was found in only 1 case.¹⁶ In our patient’s case, however, the first biopsy did show remarkable mitotic activity. This was not the case for the second biopsy, when mature chondrocytes associated with marked calcification and ossification were prominent features (Figures 6A, 6B). We presume that, within a limited period during earlier stages of tissue maturation in SCM, mitotic activity might be a possible finding. Of note, none of the other aforementioned histologic criteria for malignancy was seen in the first or second biopsy in the present case (Figures 3, 6C).

The original idea that SCM originates from a metaplasia in the subintimal layer of the synovium, where the synovium is in direct contact with the articular cartilage, has been challenged. The high incidence of hypercellularity, binucleated cells, and cellular atypia was always an argument against a metaplastic origin for the disease. Evidence of clonal chromosomal changes, like translocation of chromosome 1218 and chromosome 5 and 6 abnormalities,^19,20 in addition to other alterations,^19,21 provide some evidence supporting a neoplastic rather than a metaplastic origin for SCM. Given the presence of mitosis in the present case, the lack of mitotic activity in SCM, as stated by other authors,²² is not a universal feature and cannot be used as an argument against a neoplastic origin for SCM.

Although mitotic activity is uncommon in SCM, the present case illustrates the possible presence of mitotic activity in GSSCM. The simple presence of mitotic activity, a common finding in some other chondral tumors,23,24 does not preclude the diagnosis of benign SCM, as suggested before,8 and correlation of the clinical and radiologic manifestations with histopathologic findings is crucial for a correct diagnosis.

Congenital absence of the anterior cruciate ligament (ACL) is a rare occurrence and has been seen most often in conjunction with conditions such as knee dislocation, knee dysplasia, proximal focal femoral deficiency, and fibular hemimelia.

We report on the incidental finding of ACL aplasia in a patient with a medial meniscal tear and history of leg-length discrepancy. Similar to earlier cases, this patient had hypertrophy of the meniscofemoral ligament of Humphrey, which likely provided stability. This case report emphasizes the importance of distinguishing between a stable and an unstable knee in congenital absence of the ACL. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 20-year-old woman presented for orthopedic evaluation with worsening medial left knee pain. Her pain was intermittent in nature, occurring about every 1 to 2 months and of 1 to 2 days’ duration. Onset was while using the elliptical machine, walking on uneven ground, or navigating stairs. She denied any buckling, catching, locking, instability, or swelling.

Her history was significant for a breech delivery and leg anisomelia, for which she had a contralateral distal femoral and proximal tibial percutaneous epiphysiodesis performed at age 10 years. Family history was negative for limb deformities.

Physical examination was notable for absence of global ligamentous laxity, overall valgus alignment of the left lower extremity, minimally decreased motion, trace effusion, positive medial joint line tenderness, positive McMurray test, and 1+ Lachman test with guarding on pivot shift testing.

Plain films showed valgus alignment with narrowing of the lateral compartment, narrow intercondylar notch, and hypoplasia of the tibial eminences and lateral femoral condyle (Figure 1). Magnetic resonance imaging showed a large tear in the posterior horn of the medial meniscus, hypertrophy of the meniscofemoral ligament of Humphrey (Figure 2A), and nonvisualization of the ACL with a small remnant (Figure 2B).

Arthroscopy showed complete absence of fibers of the ACL, hypertrophy of the meniscofemoral ligament of Humphrey, and a large posterior horn medial meniscal tear. A partial medial meniscectomy was performed. More than 2 years after surgery, the patient was doing very well without pain or instability, and was exercising regularly without difficulty.

Discussion

Our patient had left-sided congenital absence of the ACL with associated limb-length discrepancy of more than 2.5 cm. Isolated absence of the ACL has been described in a few case reports in the literature. Congenital ACL absence has most often been found in association with conditions such as knee dislocation (occurring with a frequency of .017/1000 births),¹ knee dysplasia,^2,3 fibular hemimelia,⁴ and proximal focal femoral deficiency.⁵ Johansson and Aparisi^5,6 linked the finding of ACL absence with instability in those patients with known limb-length discrepancy and symptomatic instability. This report presents a patient who has congenital absence of the ACL in a foreshortened limb and torn medial meniscus. The classification of the patient’s cruciate dysplasia would be type I, as described by Manner and colleagues.⁷ The incidence of meniscal tears in association with congenital ACL absence is unknown. There have been reports of absence of the ACL associated with a ring meniscus,⁸ absence of both cruciate ligaments and menisci,⁹ and a bucket-handle tear of the medial meniscus.¹⁰

Gabos and colleagues⁴ recommend reconstructive surgery for patients with congenital absence of the ACL and symptomatic knee instability. Limb lengthening/shortening and realignment procedures have allowed patients such as ours to have functionally anatomic limbs and high activity levels. Surgical treatment is pursued to restore mechanical alignment and stability. Our patient had no symptoms of instability.

Similar to 3 of the 4 patients presented by Gabos and colleagues,⁴ our patient had marked hypertrophy of the meniscofemoral ligament of Humphrey. The report by Gabos and colleagues⁴ of this finding was the first in the literature. The hypertrophy of this ligament suggests it has a role in stabilizing the knee with a congenitally absent ACL. Our patient had no instability in her left knee but presented because of episodes of pain.

Of significant concern is the long-term outcome of patients with congenital ACL aplasia. Crawford and colleagues¹¹ reported 11 patients with ACL deficiency and fibular hemimelia at a mean age of 37 years, showing similar functional outcomes  to age-matched controls. However, there was no radiographic follow-up reported in regard to the development of osteoarthritis. To our knowledge, there have been no series published comparing surgical and nonsurgical treatment of congenital absence of the ACL. In the study by Gabos and colleagues,⁴ all patients were treated with reconstruction because these patients had symptomatic instability.

Conclusion

This report presents a patient whose symptoms improved after resection of her medial meniscal tear. This patient will be followed long-term to delineate her clinical course and to monitor for instability and/or development of osteoarthritis. Future studies should compare the treatment of congenital absence of the ACL with reconstruction and with conservative management.

Congenital absence of the anterior cruciate ligament (ACL) is a rare occurrence and has been seen most often in conjunction with conditions such as knee dislocation, knee dysplasia, proximal focal femoral deficiency, and fibular hemimelia.

We report on the incidental finding of ACL aplasia in a patient with a medial meniscal tear and history of leg-length discrepancy. Similar to earlier cases, this patient had hypertrophy of the meniscofemoral ligament of Humphrey, which likely provided stability. This case report emphasizes the importance of distinguishing between a stable and an unstable knee in congenital absence of the ACL. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 20-year-old woman presented for orthopedic evaluation with worsening medial left knee pain. Her pain was intermittent in nature, occurring about every 1 to 2 months and of 1 to 2 days’ duration. Onset was while using the elliptical machine, walking on uneven ground, or navigating stairs. She denied any buckling, catching, locking, instability, or swelling.

Her history was significant for a breech delivery and leg anisomelia, for which she had a contralateral distal femoral and proximal tibial percutaneous epiphysiodesis performed at age 10 years. Family history was negative for limb deformities.

Physical examination was notable for absence of global ligamentous laxity, overall valgus alignment of the left lower extremity, minimally decreased motion, trace effusion, positive medial joint line tenderness, positive McMurray test, and 1+ Lachman test with guarding on pivot shift testing.

Plain films showed valgus alignment with narrowing of the lateral compartment, narrow intercondylar notch, and hypoplasia of the tibial eminences and lateral femoral condyle (Figure 1). Magnetic resonance imaging showed a large tear in the posterior horn of the medial meniscus, hypertrophy of the meniscofemoral ligament of Humphrey (Figure 2A), and nonvisualization of the ACL with a small remnant (Figure 2B).

Arthroscopy showed complete absence of fibers of the ACL, hypertrophy of the meniscofemoral ligament of Humphrey, and a large posterior horn medial meniscal tear. A partial medial meniscectomy was performed. More than 2 years after surgery, the patient was doing very well without pain or instability, and was exercising regularly without difficulty.

Discussion

Our patient had left-sided congenital absence of the ACL with associated limb-length discrepancy of more than 2.5 cm. Isolated absence of the ACL has been described in a few case reports in the literature. Congenital ACL absence has most often been found in association with conditions such as knee dislocation (occurring with a frequency of .017/1000 births),¹ knee dysplasia,^2,3 fibular hemimelia,⁴ and proximal focal femoral deficiency.⁵ Johansson and Aparisi^5,6 linked the finding of ACL absence with instability in those patients with known limb-length discrepancy and symptomatic instability. This report presents a patient who has congenital absence of the ACL in a foreshortened limb and torn medial meniscus. The classification of the patient’s cruciate dysplasia would be type I, as described by Manner and colleagues.⁷ The incidence of meniscal tears in association with congenital ACL absence is unknown. There have been reports of absence of the ACL associated with a ring meniscus,⁸ absence of both cruciate ligaments and menisci,⁹ and a bucket-handle tear of the medial meniscus.¹⁰

Gabos and colleagues⁴ recommend reconstructive surgery for patients with congenital absence of the ACL and symptomatic knee instability. Limb lengthening/shortening and realignment procedures have allowed patients such as ours to have functionally anatomic limbs and high activity levels. Surgical treatment is pursued to restore mechanical alignment and stability. Our patient had no symptoms of instability.

Similar to 3 of the 4 patients presented by Gabos and colleagues,⁴ our patient had marked hypertrophy of the meniscofemoral ligament of Humphrey. The report by Gabos and colleagues⁴ of this finding was the first in the literature. The hypertrophy of this ligament suggests it has a role in stabilizing the knee with a congenitally absent ACL. Our patient had no instability in her left knee but presented because of episodes of pain.

Of significant concern is the long-term outcome of patients with congenital ACL aplasia. Crawford and colleagues¹¹ reported 11 patients with ACL deficiency and fibular hemimelia at a mean age of 37 years, showing similar functional outcomes  to age-matched controls. However, there was no radiographic follow-up reported in regard to the development of osteoarthritis. To our knowledge, there have been no series published comparing surgical and nonsurgical treatment of congenital absence of the ACL. In the study by Gabos and colleagues,⁴ all patients were treated with reconstruction because these patients had symptomatic instability.

Conclusion

This report presents a patient whose symptoms improved after resection of her medial meniscal tear. This patient will be followed long-term to delineate her clinical course and to monitor for instability and/or development of osteoarthritis. Future studies should compare the treatment of congenital absence of the ACL with reconstruction and with conservative management.

Congenital absence of the anterior cruciate ligament (ACL) is a rare occurrence and has been seen most often in conjunction with conditions such as knee dislocation, knee dysplasia, proximal focal femoral deficiency, and fibular hemimelia.

We report on the incidental finding of ACL aplasia in a patient with a medial meniscal tear and history of leg-length discrepancy. Similar to earlier cases, this patient had hypertrophy of the meniscofemoral ligament of Humphrey, which likely provided stability. This case report emphasizes the importance of distinguishing between a stable and an unstable knee in congenital absence of the ACL. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 20-year-old woman presented for orthopedic evaluation with worsening medial left knee pain. Her pain was intermittent in nature, occurring about every 1 to 2 months and of 1 to 2 days’ duration. Onset was while using the elliptical machine, walking on uneven ground, or navigating stairs. She denied any buckling, catching, locking, instability, or swelling.

Her history was significant for a breech delivery and leg anisomelia, for which she had a contralateral distal femoral and proximal tibial percutaneous epiphysiodesis performed at age 10 years. Family history was negative for limb deformities.

Physical examination was notable for absence of global ligamentous laxity, overall valgus alignment of the left lower extremity, minimally decreased motion, trace effusion, positive medial joint line tenderness, positive McMurray test, and 1+ Lachman test with guarding on pivot shift testing.

Plain films showed valgus alignment with narrowing of the lateral compartment, narrow intercondylar notch, and hypoplasia of the tibial eminences and lateral femoral condyle (Figure 1). Magnetic resonance imaging showed a large tear in the posterior horn of the medial meniscus, hypertrophy of the meniscofemoral ligament of Humphrey (Figure 2A), and nonvisualization of the ACL with a small remnant (Figure 2B).

Arthroscopy showed complete absence of fibers of the ACL, hypertrophy of the meniscofemoral ligament of Humphrey, and a large posterior horn medial meniscal tear. A partial medial meniscectomy was performed. More than 2 years after surgery, the patient was doing very well without pain or instability, and was exercising regularly without difficulty.

Discussion

Our patient had left-sided congenital absence of the ACL with associated limb-length discrepancy of more than 2.5 cm. Isolated absence of the ACL has been described in a few case reports in the literature. Congenital ACL absence has most often been found in association with conditions such as knee dislocation (occurring with a frequency of .017/1000 births),¹ knee dysplasia,^2,3 fibular hemimelia,⁴ and proximal focal femoral deficiency.⁵ Johansson and Aparisi^5,6 linked the finding of ACL absence with instability in those patients with known limb-length discrepancy and symptomatic instability. This report presents a patient who has congenital absence of the ACL in a foreshortened limb and torn medial meniscus. The classification of the patient’s cruciate dysplasia would be type I, as described by Manner and colleagues.⁷ The incidence of meniscal tears in association with congenital ACL absence is unknown. There have been reports of absence of the ACL associated with a ring meniscus,⁸ absence of both cruciate ligaments and menisci,⁹ and a bucket-handle tear of the medial meniscus.¹⁰

Gabos and colleagues⁴ recommend reconstructive surgery for patients with congenital absence of the ACL and symptomatic knee instability. Limb lengthening/shortening and realignment procedures have allowed patients such as ours to have functionally anatomic limbs and high activity levels. Surgical treatment is pursued to restore mechanical alignment and stability. Our patient had no symptoms of instability.

Similar to 3 of the 4 patients presented by Gabos and colleagues,⁴ our patient had marked hypertrophy of the meniscofemoral ligament of Humphrey. The report by Gabos and colleagues⁴ of this finding was the first in the literature. The hypertrophy of this ligament suggests it has a role in stabilizing the knee with a congenitally absent ACL. Our patient had no instability in her left knee but presented because of episodes of pain.

Of significant concern is the long-term outcome of patients with congenital ACL aplasia. Crawford and colleagues¹¹ reported 11 patients with ACL deficiency and fibular hemimelia at a mean age of 37 years, showing similar functional outcomes  to age-matched controls. However, there was no radiographic follow-up reported in regard to the development of osteoarthritis. To our knowledge, there have been no series published comparing surgical and nonsurgical treatment of congenital absence of the ACL. In the study by Gabos and colleagues,⁴ all patients were treated with reconstruction because these patients had symptomatic instability.

Conclusion

This report presents a patient whose symptoms improved after resection of her medial meniscal tear. This patient will be followed long-term to delineate her clinical course and to monitor for instability and/or development of osteoarthritis. Future studies should compare the treatment of congenital absence of the ACL with reconstruction and with conservative management.

Anterior hip dislocations have been reported to account for approximately 5% to 10% of all hip dislocations.¹ Epstein and Wiss² originally divided anterior hip dislocations into superior (type I, including pubic or subspinous) and inferior (type II, including obturator and perineal) dislocations. This classification was further subdivided based on the presence of either no associated fracture (type A), fracture of the femoral head or neck (FNF; type B), or fracture of the acetabulum (type C).³ Of all anterior hip dislocations, it has been reported that the inferior or obturator type of dislocation is more common, constituting approximately 70% of all anterior dislocations.⁴ In 1943, Pringle⁵ described the mechanism of obturator dislocation as simultaneous abduction, flexion, and external rotation of the hip. Our literature search found only 2 case reports in non-English-language journals of a complete FNF associated with an attempted reduction of an anterior hip dislocation.^6,7 Indentation fractures of the femoral head have been more commonly reported than FNFs, with a reported incidence of 35% to 55% after anterior dislocation.^4,8 DeLee and colleagues⁸ also found that those patients with indentation fractures were at a higher risk for developing avascular necrosis of the femoral head in addition to being more likely to report poor or fair function of the hip 2 years after reduction.

There have been a number of different reduction maneuvers for anterior dislocation of hips published in the literature. Epstein and Harvey⁹ advocated reduction by traction in the line of the femur with the hip flexed and in gentle internal rotation and abduction while the patient was under general anesthesia. Toms and Williams,¹⁰ however, recommended adduction with gradual release of the longitudinal traction. Polesky and Polesky¹¹ described a reduction method involving sharp internal rotation, which was found to be associated with FNF. The patient provided written informed consent for print and electronic publication of this case report, and approval was obtained from the Emory University Institutional Review Board.

Case Report

The patient was a 73-year-old woman, an independent ambulator with minimal antecedent hip pain, who, as a pedestrian, was struck by a heavy-duty pickup truck at low velocity. She was flown to our level I trauma center from an outside hospital. The patient arrived hemodynamically stable, with a Glasgow Coma Scale score of 15 and with major complaints of right shoulder and right hip pain. She had a positive Focused Assessment with Sonography for Trauma (FAST), and underwent a subsequent urgent chest, abdomen, and pelvis computed tomography (CT) scan for further investigation. CT showed a grade 1 liver laceration. Her anteroposterior (AP) pelvic radiograph and pelvic CT scan showed an anterior hip dislocation with the femoral head located adjacent to the obturator foramen (Figures 1, 2). The AP pelvic radiograph and pelvic CT scan were scrutinized extensively before reduction to rule out a possible FNF. Comparing the right and left femoral necks through multiple axial CT images showed no obvious differences between the 2 sides (Figures 3, 4). Her only other orthopedic injury was an inferior shoulder dislocation. It is not routine for the general surgery trauma team to obtain a pelvic CT scan prior to involvement of the orthopedic service and prompt reduction of a hip dislocation. Upon initial examination of her right hip, it was fixed in slight flexion and external rotation; she was neurovascularly intact.

After being cleared by the trauma service, the patient provided informed consent for closed reduction of the hip and shoulder under conscious sedation, performed by the emergency department (ED) staff. She received intravenous fentanyl and midazolam, and the reduction was attempted. The reduction maneuver was performed with gentle inline traction, adduction, and internal rotation and extension. There was an audible clunk, and the hip was thought to be reduced and stable. The right leg lower extremity was placed into a knee immobilizer and she remained neurovascularly intact. The shoulder was reduced. After the procedure, the patient had an episode of hypoxia requiring oxygenation via a bag valve mask by the ED staff. Postreduction radiographs confirmed reduction of the right shoulder; however, they also showed a FNF with the femoral head retained near the obturator foramen (Figures 5, 6). The patient and her family were informed of the fracture, and a total hip arthroplasty (THA) was recommended, given her pre-injury mild symptomatic osteoarthritis in the hip and her age. The patient was admitted to the intensive care unit for cardiopulmonary monitoring and was found to have a troponin leak on hospital day 1. She was evaluated by the cardiology service; serial electrocardiograms and troponins ruled out acute myocardial infarction. The patient was cleared for surgery on hospital day 4.

On hospital day 5, she underwent a right THA via a Kocher-Langenbeck approach. The patient’s femoral head was found to be anterior and laterally adjacent to her ischial tuberosity with an indentation fracture. The sciatic nerve was identified and found to be intact. A metal-on-polyethylene Stryker Accolade femoral component and Trident acetabular shell were implanted, and a posterior capsular repair was performed (Figure 7).

The patient tolerated the procedure well, and her postoperative course was uneventful. She was discharged to a subacute rehabilitation facility on postoperative day 3. The patient returned for her 2-week postoperative visit ambulating without assistance. At her last follow-up visit, approximately 6 weeks after surgery, she was a functionally independent community ambulator. Phone conversations with her private orthopedist at 6 months confirmed continued ambulation without problems.

Discussion

This case report of a complication that occurred in our institution has resulted in a change in our protocol for treatment of geriatric anterior hip dislocations. Our institution is a level I trauma center, and traumatic hip dislocations are relatively common, occurring usually in young patients with high-energy trauma. Although somewhat controversial, it is generally assumed that the incidence of avascular necrosis of the femoral head after dislocation of the hip is correlated with the time interval from dislocation to reduction of the hip. Therefore, our protocol for hip dislocations of the hip in young trauma patients is urgent reduction in the ED under appropriate analgesia and muscle relaxation.

In this case report, the patient was older than 65 years with radiographic evidence of possible impingement and postsurgical evidence of impingement of the femoral head in the obturator foremen (Figures 1, 2, 8). In addition, the patient was significantly osteopenic radiographically. An attempted reduction in the ED resulted in FNF requiring THA (Figures 5, 6, 9). After discussion of this complication in our institution’s morbidity and mortality conference, we have developed a protocol for the geriatric patient (older than 65 years) with a traumatic hip dislocation. These patients will undergo attempted reduction under controlled analgesia and muscle relaxation in the operating room (OR) with an attending surgeon present, ideally, an attending surgeon comfortable with arthroplasty in a terminally cleaned OR room. Our institution’s surgical site infection rate after total joint arthroplasty has significantly decreased with improved patient selection and the use of terminally cleaned OR rooms. Because our policy is to perform closed reduction of dislocated hips in an urgent manner, if there is not a terminally clean room or an arthroplasty-trained attending orthopedic surgeon available, then informed consent with discussion of the possibility of fracture requiring a subsequent arthroplasty should be obtained from the patient before the attempted reduction.

After review of the available literature, we believe that this case highlights some of the important treatment principles when treating anterior hip dislocations in the ED. The relatively high incidence of indentation fractures of the femoral head with obturator dislocations puts these fractures at higher risk for possible impingement around the obturator ring. This impingement, coupled with preexisting osteopenia, can predispose these dislocations to FNF, if appropriate analgesia and sedation are not obtained and gentle reduction is not performed. In addition, while it may not be time- or cost-effective to perform closed reduction on every hip dislocation, we bring geriatric patients with radiographic osteopenia to the OR for more controlled reductions. In the informed consent discussion, the possibility of FNF is mentioned, and the patient and family are told that an elective total hip replacement will be performed if this complication occurs.

We consider the following to be risk factors for closed reductions of anterior hip dislocations: (1) preexisting osteopenia on plain films, (2) age greater than 65 years, and (3) radiographic femoral head impingement on the surrounding bony pelvis. We continue to consider closed reduction of both anterior and posterior hip dislocations as urgent (within 6 hours from time of dislocation). This case adds to the existing literature on the risk of FNF with closed reduction of obturator hip dislocations, and we hope that it will encourage further study into the safest and most cost-effective reduction protocol.

Anterior hip dislocations have been reported to account for approximately 5% to 10% of all hip dislocations.¹ Epstein and Wiss² originally divided anterior hip dislocations into superior (type I, including pubic or subspinous) and inferior (type II, including obturator and perineal) dislocations. This classification was further subdivided based on the presence of either no associated fracture (type A), fracture of the femoral head or neck (FNF; type B), or fracture of the acetabulum (type C).³ Of all anterior hip dislocations, it has been reported that the inferior or obturator type of dislocation is more common, constituting approximately 70% of all anterior dislocations.⁴ In 1943, Pringle⁵ described the mechanism of obturator dislocation as simultaneous abduction, flexion, and external rotation of the hip. Our literature search found only 2 case reports in non-English-language journals of a complete FNF associated with an attempted reduction of an anterior hip dislocation.^6,7 Indentation fractures of the femoral head have been more commonly reported than FNFs, with a reported incidence of 35% to 55% after anterior dislocation.^4,8 DeLee and colleagues⁸ also found that those patients with indentation fractures were at a higher risk for developing avascular necrosis of the femoral head in addition to being more likely to report poor or fair function of the hip 2 years after reduction.

There have been a number of different reduction maneuvers for anterior dislocation of hips published in the literature. Epstein and Harvey⁹ advocated reduction by traction in the line of the femur with the hip flexed and in gentle internal rotation and abduction while the patient was under general anesthesia. Toms and Williams,¹⁰ however, recommended adduction with gradual release of the longitudinal traction. Polesky and Polesky¹¹ described a reduction method involving sharp internal rotation, which was found to be associated with FNF. The patient provided written informed consent for print and electronic publication of this case report, and approval was obtained from the Emory University Institutional Review Board.

Case Report

The patient was a 73-year-old woman, an independent ambulator with minimal antecedent hip pain, who, as a pedestrian, was struck by a heavy-duty pickup truck at low velocity. She was flown to our level I trauma center from an outside hospital. The patient arrived hemodynamically stable, with a Glasgow Coma Scale score of 15 and with major complaints of right shoulder and right hip pain. She had a positive Focused Assessment with Sonography for Trauma (FAST), and underwent a subsequent urgent chest, abdomen, and pelvis computed tomography (CT) scan for further investigation. CT showed a grade 1 liver laceration. Her anteroposterior (AP) pelvic radiograph and pelvic CT scan showed an anterior hip dislocation with the femoral head located adjacent to the obturator foramen (Figures 1, 2). The AP pelvic radiograph and pelvic CT scan were scrutinized extensively before reduction to rule out a possible FNF. Comparing the right and left femoral necks through multiple axial CT images showed no obvious differences between the 2 sides (Figures 3, 4). Her only other orthopedic injury was an inferior shoulder dislocation. It is not routine for the general surgery trauma team to obtain a pelvic CT scan prior to involvement of the orthopedic service and prompt reduction of a hip dislocation. Upon initial examination of her right hip, it was fixed in slight flexion and external rotation; she was neurovascularly intact.

After being cleared by the trauma service, the patient provided informed consent for closed reduction of the hip and shoulder under conscious sedation, performed by the emergency department (ED) staff. She received intravenous fentanyl and midazolam, and the reduction was attempted. The reduction maneuver was performed with gentle inline traction, adduction, and internal rotation and extension. There was an audible clunk, and the hip was thought to be reduced and stable. The right leg lower extremity was placed into a knee immobilizer and she remained neurovascularly intact. The shoulder was reduced. After the procedure, the patient had an episode of hypoxia requiring oxygenation via a bag valve mask by the ED staff. Postreduction radiographs confirmed reduction of the right shoulder; however, they also showed a FNF with the femoral head retained near the obturator foramen (Figures 5, 6). The patient and her family were informed of the fracture, and a total hip arthroplasty (THA) was recommended, given her pre-injury mild symptomatic osteoarthritis in the hip and her age. The patient was admitted to the intensive care unit for cardiopulmonary monitoring and was found to have a troponin leak on hospital day 1. She was evaluated by the cardiology service; serial electrocardiograms and troponins ruled out acute myocardial infarction. The patient was cleared for surgery on hospital day 4.

On hospital day 5, she underwent a right THA via a Kocher-Langenbeck approach. The patient’s femoral head was found to be anterior and laterally adjacent to her ischial tuberosity with an indentation fracture. The sciatic nerve was identified and found to be intact. A metal-on-polyethylene Stryker Accolade femoral component and Trident acetabular shell were implanted, and a posterior capsular repair was performed (Figure 7).

The patient tolerated the procedure well, and her postoperative course was uneventful. She was discharged to a subacute rehabilitation facility on postoperative day 3. The patient returned for her 2-week postoperative visit ambulating without assistance. At her last follow-up visit, approximately 6 weeks after surgery, she was a functionally independent community ambulator. Phone conversations with her private orthopedist at 6 months confirmed continued ambulation without problems.

Discussion

This case report of a complication that occurred in our institution has resulted in a change in our protocol for treatment of geriatric anterior hip dislocations. Our institution is a level I trauma center, and traumatic hip dislocations are relatively common, occurring usually in young patients with high-energy trauma. Although somewhat controversial, it is generally assumed that the incidence of avascular necrosis of the femoral head after dislocation of the hip is correlated with the time interval from dislocation to reduction of the hip. Therefore, our protocol for hip dislocations of the hip in young trauma patients is urgent reduction in the ED under appropriate analgesia and muscle relaxation.

In this case report, the patient was older than 65 years with radiographic evidence of possible impingement and postsurgical evidence of impingement of the femoral head in the obturator foremen (Figures 1, 2, 8). In addition, the patient was significantly osteopenic radiographically. An attempted reduction in the ED resulted in FNF requiring THA (Figures 5, 6, 9). After discussion of this complication in our institution’s morbidity and mortality conference, we have developed a protocol for the geriatric patient (older than 65 years) with a traumatic hip dislocation. These patients will undergo attempted reduction under controlled analgesia and muscle relaxation in the operating room (OR) with an attending surgeon present, ideally, an attending surgeon comfortable with arthroplasty in a terminally cleaned OR room. Our institution’s surgical site infection rate after total joint arthroplasty has significantly decreased with improved patient selection and the use of terminally cleaned OR rooms. Because our policy is to perform closed reduction of dislocated hips in an urgent manner, if there is not a terminally clean room or an arthroplasty-trained attending orthopedic surgeon available, then informed consent with discussion of the possibility of fracture requiring a subsequent arthroplasty should be obtained from the patient before the attempted reduction.

After review of the available literature, we believe that this case highlights some of the important treatment principles when treating anterior hip dislocations in the ED. The relatively high incidence of indentation fractures of the femoral head with obturator dislocations puts these fractures at higher risk for possible impingement around the obturator ring. This impingement, coupled with preexisting osteopenia, can predispose these dislocations to FNF, if appropriate analgesia and sedation are not obtained and gentle reduction is not performed. In addition, while it may not be time- or cost-effective to perform closed reduction on every hip dislocation, we bring geriatric patients with radiographic osteopenia to the OR for more controlled reductions. In the informed consent discussion, the possibility of FNF is mentioned, and the patient and family are told that an elective total hip replacement will be performed if this complication occurs.

We consider the following to be risk factors for closed reductions of anterior hip dislocations: (1) preexisting osteopenia on plain films, (2) age greater than 65 years, and (3) radiographic femoral head impingement on the surrounding bony pelvis. We continue to consider closed reduction of both anterior and posterior hip dislocations as urgent (within 6 hours from time of dislocation). This case adds to the existing literature on the risk of FNF with closed reduction of obturator hip dislocations, and we hope that it will encourage further study into the safest and most cost-effective reduction protocol.

Anterior hip dislocations have been reported to account for approximately 5% to 10% of all hip dislocations.¹ Epstein and Wiss² originally divided anterior hip dislocations into superior (type I, including pubic or subspinous) and inferior (type II, including obturator and perineal) dislocations. This classification was further subdivided based on the presence of either no associated fracture (type A), fracture of the femoral head or neck (FNF; type B), or fracture of the acetabulum (type C).³ Of all anterior hip dislocations, it has been reported that the inferior or obturator type of dislocation is more common, constituting approximately 70% of all anterior dislocations.⁴ In 1943, Pringle⁵ described the mechanism of obturator dislocation as simultaneous abduction, flexion, and external rotation of the hip. Our literature search found only 2 case reports in non-English-language journals of a complete FNF associated with an attempted reduction of an anterior hip dislocation.^6,7 Indentation fractures of the femoral head have been more commonly reported than FNFs, with a reported incidence of 35% to 55% after anterior dislocation.^4,8 DeLee and colleagues⁸ also found that those patients with indentation fractures were at a higher risk for developing avascular necrosis of the femoral head in addition to being more likely to report poor or fair function of the hip 2 years after reduction.

There have been a number of different reduction maneuvers for anterior dislocation of hips published in the literature. Epstein and Harvey⁹ advocated reduction by traction in the line of the femur with the hip flexed and in gentle internal rotation and abduction while the patient was under general anesthesia. Toms and Williams,¹⁰ however, recommended adduction with gradual release of the longitudinal traction. Polesky and Polesky¹¹ described a reduction method involving sharp internal rotation, which was found to be associated with FNF. The patient provided written informed consent for print and electronic publication of this case report, and approval was obtained from the Emory University Institutional Review Board.

Case Report

The patient was a 73-year-old woman, an independent ambulator with minimal antecedent hip pain, who, as a pedestrian, was struck by a heavy-duty pickup truck at low velocity. She was flown to our level I trauma center from an outside hospital. The patient arrived hemodynamically stable, with a Glasgow Coma Scale score of 15 and with major complaints of right shoulder and right hip pain. She had a positive Focused Assessment with Sonography for Trauma (FAST), and underwent a subsequent urgent chest, abdomen, and pelvis computed tomography (CT) scan for further investigation. CT showed a grade 1 liver laceration. Her anteroposterior (AP) pelvic radiograph and pelvic CT scan showed an anterior hip dislocation with the femoral head located adjacent to the obturator foramen (Figures 1, 2). The AP pelvic radiograph and pelvic CT scan were scrutinized extensively before reduction to rule out a possible FNF. Comparing the right and left femoral necks through multiple axial CT images showed no obvious differences between the 2 sides (Figures 3, 4). Her only other orthopedic injury was an inferior shoulder dislocation. It is not routine for the general surgery trauma team to obtain a pelvic CT scan prior to involvement of the orthopedic service and prompt reduction of a hip dislocation. Upon initial examination of her right hip, it was fixed in slight flexion and external rotation; she was neurovascularly intact.

After being cleared by the trauma service, the patient provided informed consent for closed reduction of the hip and shoulder under conscious sedation, performed by the emergency department (ED) staff. She received intravenous fentanyl and midazolam, and the reduction was attempted. The reduction maneuver was performed with gentle inline traction, adduction, and internal rotation and extension. There was an audible clunk, and the hip was thought to be reduced and stable. The right leg lower extremity was placed into a knee immobilizer and she remained neurovascularly intact. The shoulder was reduced. After the procedure, the patient had an episode of hypoxia requiring oxygenation via a bag valve mask by the ED staff. Postreduction radiographs confirmed reduction of the right shoulder; however, they also showed a FNF with the femoral head retained near the obturator foramen (Figures 5, 6). The patient and her family were informed of the fracture, and a total hip arthroplasty (THA) was recommended, given her pre-injury mild symptomatic osteoarthritis in the hip and her age. The patient was admitted to the intensive care unit for cardiopulmonary monitoring and was found to have a troponin leak on hospital day 1. She was evaluated by the cardiology service; serial electrocardiograms and troponins ruled out acute myocardial infarction. The patient was cleared for surgery on hospital day 4.

On hospital day 5, she underwent a right THA via a Kocher-Langenbeck approach. The patient’s femoral head was found to be anterior and laterally adjacent to her ischial tuberosity with an indentation fracture. The sciatic nerve was identified and found to be intact. A metal-on-polyethylene Stryker Accolade femoral component and Trident acetabular shell were implanted, and a posterior capsular repair was performed (Figure 7).

The patient tolerated the procedure well, and her postoperative course was uneventful. She was discharged to a subacute rehabilitation facility on postoperative day 3. The patient returned for her 2-week postoperative visit ambulating without assistance. At her last follow-up visit, approximately 6 weeks after surgery, she was a functionally independent community ambulator. Phone conversations with her private orthopedist at 6 months confirmed continued ambulation without problems.

Discussion

This case report of a complication that occurred in our institution has resulted in a change in our protocol for treatment of geriatric anterior hip dislocations. Our institution is a level I trauma center, and traumatic hip dislocations are relatively common, occurring usually in young patients with high-energy trauma. Although somewhat controversial, it is generally assumed that the incidence of avascular necrosis of the femoral head after dislocation of the hip is correlated with the time interval from dislocation to reduction of the hip. Therefore, our protocol for hip dislocations of the hip in young trauma patients is urgent reduction in the ED under appropriate analgesia and muscle relaxation.

In this case report, the patient was older than 65 years with radiographic evidence of possible impingement and postsurgical evidence of impingement of the femoral head in the obturator foremen (Figures 1, 2, 8). In addition, the patient was significantly osteopenic radiographically. An attempted reduction in the ED resulted in FNF requiring THA (Figures 5, 6, 9). After discussion of this complication in our institution’s morbidity and mortality conference, we have developed a protocol for the geriatric patient (older than 65 years) with a traumatic hip dislocation. These patients will undergo attempted reduction under controlled analgesia and muscle relaxation in the operating room (OR) with an attending surgeon present, ideally, an attending surgeon comfortable with arthroplasty in a terminally cleaned OR room. Our institution’s surgical site infection rate after total joint arthroplasty has significantly decreased with improved patient selection and the use of terminally cleaned OR rooms. Because our policy is to perform closed reduction of dislocated hips in an urgent manner, if there is not a terminally clean room or an arthroplasty-trained attending orthopedic surgeon available, then informed consent with discussion of the possibility of fracture requiring a subsequent arthroplasty should be obtained from the patient before the attempted reduction.

After review of the available literature, we believe that this case highlights some of the important treatment principles when treating anterior hip dislocations in the ED. The relatively high incidence of indentation fractures of the femoral head with obturator dislocations puts these fractures at higher risk for possible impingement around the obturator ring. This impingement, coupled with preexisting osteopenia, can predispose these dislocations to FNF, if appropriate analgesia and sedation are not obtained and gentle reduction is not performed. In addition, while it may not be time- or cost-effective to perform closed reduction on every hip dislocation, we bring geriatric patients with radiographic osteopenia to the OR for more controlled reductions. In the informed consent discussion, the possibility of FNF is mentioned, and the patient and family are told that an elective total hip replacement will be performed if this complication occurs.

We consider the following to be risk factors for closed reductions of anterior hip dislocations: (1) preexisting osteopenia on plain films, (2) age greater than 65 years, and (3) radiographic femoral head impingement on the surrounding bony pelvis. We continue to consider closed reduction of both anterior and posterior hip dislocations as urgent (within 6 hours from time of dislocation). This case adds to the existing literature on the risk of FNF with closed reduction of obturator hip dislocations, and we hope that it will encourage further study into the safest and most cost-effective reduction protocol.