Abstract
1. The technique of arthrography in congenital displacement of the hip is described. No complications have been encountered in a series of over 200 examinations. The interpretation of the arthrographs is discussed.
2. It is suggested that the abnormal hips may be classified in three degrees: 1) Primary instability; 2) partial displacement without interposition of soft tissue; 3) complete displacement with interposition of soft tissue between head and socket.
3. Two types of complete displacement or dislocation are recognised: 1) the "tight" dislocation; 2) the "loose" dislocation. In the latter there is marked displacement of the femoral head, and arthrography done before reduction demonstrates interposition of a fold of capsule lying in front of the inverted limbus.
4. Arthrography is of special help in making the diagnosis between partial displacement with eversion of the labrum and "tight" dislocation with an interposed limbus. It is helpful too in establishing the cause of failure of reduction.
