[Nerve compression syndrome caused by synovial cyst of the hip joint].

Synovitis of the iliopectineal bursa have been described in pigmented villanodular synovitis, synovial chondromatosis, rheumatoid arthritis, osteoarthritis and necrosis of the femoral head. We report a case of enlargement of such a cyst in necrosis of femoral head and consecutive osteoarthritis, leading to entrapment of the femoral nerve. Simple drainage of the cyst did resolve pain for a short period and only elimination of the primum pathologicum agens did definitively release pain, irradiating to the ipsilateral leg.