Objective: To analyse and prevent postoperative dislocation after total hip replacement (THR).
Methods: Of 850 cases operated on by THR 15 (1.7%) had postoperative dislocation. Eleven were revision cases while the other 4 were operated on their primary procedures.
Results: Postoperative dislocation after THR were found in 15 cases. Eleven cases had posterior dislocation by posterolateral approach after revision of THR. Anterior dislocation occurred in 2 cases who received lateral approach. Another two cases of dislocation were related to the design of prosthesis. Separation of polyethylene liner and metal shell in acetabular prosthesis was noted in the two cases. All the cases but 1 were reduced operatively. The cases with malpositioned prosthesis were revised operatively. Augmentation procedure was carried out to increase the strength of abductor. In one case, relocation of the great trochantor increased the strength of abductor. No redislocation was observed during follow-up.
Conclusions: Postoperative dislocation after THR are due to malpositioning of prosthesis, unbalanced bilateral soft tissues, especially the loosening of abductor. Evaluating carefully the development of the pelvis and the deviation of normal bone markers is important in addition to accurate insertion and installment of the prosthesis intraoperatively. Complete clearance of osteophytes and bone cements around the acetabulumis reqaired apart from the repairment of adjacent soft tissues. Double check of hip stability should be carried out before the closure of incision.