Inguinal mass as a late complication of hip arthroplasty. Differential diagnosis and treatment from a vascular surgical perspective.

We report on three patients with a symptomatic inguinal mass as a late complication of repetitive arthroplastic hip surgery. In one case, there was a false aneurysm and in two cases a so-called "synovial cyst". A synovial cyst is usually an enlarged iliopsoas bursa in communication with the capsule of the hip joint. Hypersecretion in arthritic joints may cause expansion of this bursa. Compression of the common femoral and external iliac veins may lead to outflow obstruction and leg swelling. The most important diagnostic tools are plain films of the hip joint and ultrasound of the groin including colour-coded assessment of the femoral vessels. Symptomatic cysts usually need removing by an anterior approach. Loose arthroplastic components can be causative and should be replaced.