Early diagnosis and treatment of hinge abduction in Legg-Perthes disease.

A review of 106 cases of Legg-Perthes disease disclosed 26 in whom a particularly poor radiographic appearance was seen. Hinge abduction was detected in 19 of these patients and was suspected but not proven in the remainder. Hinge abduction was found to occur early in the course of Legg-Perthes, and hinging frequently occurred about an unossified portion of femoral head, making detection difficult. Failure of movement of the lateral corner of the epiphysis under the edge of the acetabulum on an internally rotated and abducted radiograph is prima facie evidence of hinge abduction. Confirmation is easily obtained by arthrography. Hinging must be relieved if guidance of femoral head growth by the healthy acetabulum is to be possible. Both clinical and radiographic outcomes were worse in patients with unrelieved hinge abduction. Relief of hinging can frequently be accomplished by traction, and containment can then be maintained by appropriate surgery.