Long-term outcome of knee arthroplasty in the setting of pigmented villonodular synovitis

BackgroundPigmented villonodular synovitis (PVNS) is a rare, benign proliferation of the synovium, commonly affecting the knee. Arthroplasty can successfully manage arthrosis in this population; however, outcome data is limited. The purpose of this study was to investigate the oncologic and functional outcome of patients undergoing total knee arthroplasty (TKA) in the setting of PVNS.Methods48 patients were identified at our institution with histologically confirmed PVNS that subsequently received TKA. The cohort consisted of 28 females and 20 males with a mean age and body mass index of 61years and 29.2kg/m2. 37patients had "active" disease, defined as diffuse in 40 patients and focal in eight. Mean follow-up was 14years.ResultsThe 10-year disease free-survival was 88%. Recurrence occurred in 6 patients and was treated with synovectomy and revision arthroplasty (n=4), local excision (n=1) and transfemoral amputation (n=1). 25 patients sustained at least 1 complication, most commonly decreased knee range of motion. Complications resulted in revision TKA in 10 patients (21%). There was no difference (P=0.74) between mean pre- and postoperative ROM; however, there was a significant reduction in the number of patients with a flexion contracture >15° (P=0.03). The mean Knee Society score and functional score significantly improved following surgery (P<0.001).ConclusionsThis study indicates arthroplasty in the setting of PVNS improves patient function and reduces the presence of flexion contractures. Patients with a history of PVNS should be cautioned when undergoing arthroplasty on the elevated risk of subsequent procedures.Level of evidenceLevel III.