This study investigated 11 patients with localized pigmented villonodular s
ynovitis of the knee that was diagnosed and treated by arthroscopic techniq
ue. There were six male and five female patients between the ages of 15 and
59 years (mean, 34.6 years), Seven patients reported extension limitation
without joint line tenderness, Four of the 11 patients had a history of tra
uma before the onset of knee symptoms, All patients were treated by arthros
copic resection with partial synovectomy, The most common involved site was
the anteromedial synovium near the anterior horn of the medial meniscus (f
ive patients). The remaining cases were located in the anterior fat pad (tw
o patients), suprapatellar pouch, posteromedial compartment, medial gutter,
and the anterior horn of the lateral meniscus, Nine patients had one mass,
and the remaining patients each had two or three masses. There was no evid
ence of recurrence at followup for an average of 29.9 months (range, 24-48
months). Arthroscopy is effective in the diagnosis of localized pigmented v
illonodular synovitis with minimal morbidity, and complete arthroscopic exc
ision can be considered the definitive treatment for localized pigmented vi
llonodular synovitis.