[Synovial diseases of the hip]

Synovial diseases of the hip are often overlooked because they are far less frequent that osteoarthritis and because this joint is deep and so difficult to examine. The more important cause is septic arthritis; it requires an hospitalization in emergency. Synovial tissue may also be at the beginning of the spondylarthropathy or, more rarely, of rheumatoid arthritis. In acute forms, diagnosis must be done before any radiological destructive changes. Aspiration of the hip and synovial biopsy are necessary for the diagnosis. In subacute or chronic forms, computed tomography and/or magnetic resonance imaging are useful tools to suspect the diagnosis and to guide a biopsy.