Locking of the knee caused by an intra-articular myxoma.

A rare case of an intra-articular myxoma of the knee in a 20-year-old woman is described. She presented with a 3-month history of progressive left knee pain and locking, and was incapable of full knee joint flexion due to a mechanical obstruction. Magnetic resonance imaging (MRI) scans revealed an intra-articular mass in the patellofemoral joint. After arthroscopic examination of the knee, the mass was totally excised and histologically diagnosed as a juxta-articular myxoma. The patient's postoperative course was uneventful, and no recurrence of the tumor was detected at the 2-year follow-up evaluation. The present case demonstrates that intra-articular myxoma can produce mechanical locking of the knee. The clinical implication of this report is to present a possible new cause of knee joint locking in addition to other well-known causes. [ABSTRACT FROM AUTHOR]