Pigmented villonodular synovitis of the knee: average five-year follow-up of arthroscopic treatment.

We have reviewed the results of arthroscopic treatment of pigmented villonodular synovitis (PVNS) with reference to both recurrence and to function. Between 1985 and 1995, a single surgeon treated eight patients. At an average 5-year follow-up, all patients were interviewed and had assessment of Hospital for Special Surgery (HSS) knee score for both the affected and unaffected knees. Also recorded were age, sex, and whether disease was recurrent, localized, or diffuse. Disease recurred in 4 patients, all with diffuse PVNS, and 3 of them required a further arthroscopic synovectomy at a mean of 16 months after the index procedure. All patients had good or excellent functional results. There was no significant difference between HSS knee scores for affected and unaffected knees. Arthroscopic synovectomy is a successful treatment in patients with localized PVNS of the knee and results in a knee that is functionally not different from its unaffected partner.