[Open reduction technique].

Abstract

Closed reduction of a hip dislocation will prove even more difficult if the dislocation has existed over a longer period of time. The indication is based on several principles: An open reduction may be carried out only after an unsuccessful attempt to perform a closed reduction or at a fixed age limit (12 or 24 months) or based upon arthrographic findings. In our department, for babies up to the age of 12 months, we always try to perform a closed reduction. Between 12 to 24 months, arthrographic findings will determine the choice of method. After the age of two, as a rule, we use an open reduction. The preliminary treatment consists of longitudinal traction. Current methods of approach to the hip joint are the medial approach according to Ludloff or the frontal approach by means of an inguinal incision. With the medial approach, there is greater risk of damaging the circumflex artery; also, a higher rate of avascular necrosis of the femoral head has been observed. Therefore, we only practice the ventral approach. Mainly for cosmetic reasons, however, instead of using the Smith-Petersen procedure, we apply a pure inguinal incision proximal to the inguinal ligament. The approach is found by detaching the muscle tissue at the anterior and interior iliac spine. Medially and laterally of the pelvic ridge, though, the tissue may be left. The joint capsule may be opened in the shape of a T or a V. A t-shape incision offers a better survey, whereby the risk of damaging a vessel is somewhat higher. In addition to resection of the teres ligament, it is necessary to indent the transverse acetabular ligament. Often, aponeurotic recession of the psoas tendon must be performed as well and the labrum indented and pushed outwards before reduction. The risk of insufficient development of the acetabulum can be minimized only if the femoral head is optimally centered. If the femoral head is in a high position (i.e., if the upper ridge of the femoral metaphysis lies higher than the triradiate cartilage), a shortening osteotomy of the femur should always be performed. This is the only possibility of repositioning the femoral head without exercising exaggerated pressure. On the other hand, we are rather reticent to perform a pelvic osteotomy at the time of repositioning. For children under 2 years of age, we recommend to that the acetabulum be allowed to develop and that a pelvic osteotomy be performed at a lager period if necessary. Postoperative treatment is given for a period of 12 weeks in a hip-leg cast in the Fettweis position, followed by another 3 months in a splint. Possible complications are redislocations, avascular necrosis of the femoral head and persistent acetabular dysplasia. An optimal technique will considerably reduce the risks of such complications.