Pigmented Villonodular Synovitis: A Retrospective Multicenter Study of 237 Cases

PURPOSE To review clinical characteristics of pigmented villonodular synovitis (PVNS) in China. METHODS Electronic medical records (EMR) of four Chinese institutes were queried for patients with histologically proven PVNS between January 2005 and February 2014. Their data were collected including gender, age at diagnosis, clinical presentation, affected site, symptom duration, comorbidities, treatment strategy, recurrence and routine laboratories. RESULTS A total of 237 patients with biopsy-proven PVNS were investigated. The gender ratio was 1.35 for a female predominance (101 males and 136 females). The average age was 36 years (range, 2 to 83 years). The median delay from initial clinical symptom to diagnosis was 18 months. Main affected areas were the knee (73.84%) and the hip (18.14%). Forty patients had a clear history of joint trauma. Six patients were concurrently diagnosed with PVNS and avascular necrosis (AVN). Five patients suffered from PVNS following implantation of orthopaedic devices including artificial prosthesis, plate and wire. One hundred and twenty-nine patients underwent arthroscopic synovectomy and 108 open synovectomy. Altogether 48 patients (26 males and 22 females) had recurrence of disease. The relapse rate was 24% (knee) and 6.98% (hip), 20.93% (open surgery) and 19.44% (arthroscopy), respectively. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) rate were elevated in 45.83% and 38.41% of the patients respectively. CONCLUSIONS To our knowledge, this study is the largest sample size of PVNS patients reported as well as the largest sample of PVNS with concurrent AVN reported to date. Our outcomes suggest that PVNS shows a female predominance, occurs mostly between 20-40 years and favors the knee and hip. Recurrence is frequent, particularly in the knee. Serum ESR and CRP may be elevated in some patients. Additionally, the present study supports the theory of an association between PVNS and orthopedic surgery, which is not limited to joint replacement.