What affects the recurrence and clinical outcome of pigmented villonodular synovitis?

UNLABELLED: Studies investigating the outcome of pigmented villonodular synovitis have been restricted to certain locations or types of the disease and have not provided adequate documentation of followup. We asked the following questions: What were the recurrence rates especially when considering location and type of pigmented villonodular synovitis?; What was the long-term clinical outcome?; and Was MR imaging essential for the correct diagnosis? We retrospectively reviewed 42 of 53 consecutive patients primarily treated at our institution (19 diffuse lesions and 23 nodular lesions in 19 large joints and 23 digits of the hands or feet). Ten patients had recurrences after an average followup of 80 months (range, 26-293.8 months). Recurrences were more frequent for the diffuse type than the nodular type and in large joints rather than in digits. The average Enneking score was 92% of normal limb function indicating that surgical treatment led to good functional results. Preoperative magnetic resonance imaging results corresponded well with histologic diagnoses and intraoperative findings. LEVEL OF EVIDENCE: Therapeutic Level IV.