Localized pigmented villonodular synovitis in the knee associated with locking symptoms.

Pigmented villonodular synovitis (PVNS) occurs in the knee more frequently than other joints. Most cases involve diffuse PVNS while the localized type is relatively rare. This report describes a patient who had PVNS and a lateral meniscus injury which induced locking symptoms in the knee. A closed reduction of the meniscus tear was performed under local anesthesia. However, complete extension of the knee was not achieved and the locking symptoms persisted. MRI examination showed a neoplastic lesion measuring approximately 2 x 2 cm in the intercondylar space together with a lateral meniscus tear. The lesion was resected using arthroscopy. Histology of the resected lesion demonstrated localized PVNS. There has not been any recurrence of locking symptoms or PVNS two years after surgery. The findings in this case suggest that localized PVNS may contribute to locking symptoms in a patient with meniscal pathology.