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

Background: Pigmented 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. Methods: 48 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 61 years and 29.2 kg/m(2). 37 patients had "active" disease, defined as diffuse in 40 patients and focal in eight. Mean follow-up was 14 years. Results: The 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 degrees (P = 0.03). The mean Knee Society score and functional score significantly improved following surgery (P < 0.001). Conclusions: This 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 evidence: Level III. (C) 2017 Elsevier B.V. All rights reserved.