Giant synovial cyst causing femoral occlusion following a hip replacement. A case report and review of the literature.

Long-term follow-up of total hip replacements (THR) is essential for accurate recording of complications associated with this procedure, in particular the occurrence of wear and aseptic loosening which may warrant revision surgery. A significant proportion of patients with aseptic loosening are asymptomatic and radiological signs may be subtle and easily missed. Occasionally a synovial cyst can develop as a result of polyethylene wear debris and aseptic loosening. These cysts are usually small but can expand and become symptomatic. We describe a case where a large cyst caused sufficient extrinsic compression of the femoral vein as to occlude it. This was a potentially life-threatening complication. We emphasize the importance of clinical examination for leg swelling and groin mass in routine surveillance of total hip replacement. (Hip International 2002; 4: 394-6).