UNUSUAL MANIFESTATIONS OF PROXIMAL TIBIOFIBULAR JOINT SYNOVIAL CYSTS

Synovial cysts emanating from the proximal tibiofibular articulation a re commonly symptomatic and may progress to compromise peroneal nerve function. They may cause diagnostic confusion when they present as int raosseous masses or as soft tissue masses causing extrinsic bony erosi on. Twelve cases treated surgically are reviewed. Electromyography and nerve conduction studies were valuable in localizing the lesions to t he knee when no mass was palpable. Of the six cases involving the pero neal nerve, three required loupe or microscopic dissection of the cyst from within the epineurium. Two other cases had bony changes. Magneti c resonance imaging, though not diagnostic, is valuable in planning th e dissection.