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 61years and 29.2kg/m2. 37patients had "active" disease, defined as diffuse in 40 patients and focal in eight. Mean follow-up was 14years.

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° (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.