ABSTRACT
Objective To evaluate the efficacy of total hip replacement in patients with ankylosing spondylitis(AS) and to solve the problem often encountered during surgery. Methods One hundred and twelve hips of 98 patients with AS undergone total hip replacement were reviewed. The mean duration of follow up was 4.2 years(range, 1.5 to 8 years). The pre and postoperatively comparative study on pain, range of motion, correction of deformity and total function evaluation were conducted. Results Pain relief obtained in all but 4 hips. Mean range of motion was improved from 37.5? to 69.5? and the flexion deformity of the involved hip was corrected from mean 38.2? to 5.7?， all of the patients could take care of daily living by themselves. Complications included penetrating fracture of proximal femur in 4, sciatic nerve injury in 3, early dislocation of the hip in 2, disassociation of the acetabular component in 2 and sinking of the femoral stem in 23. Conclusion Total hip replacement is a very important and effective treatment of choice for patients with AS. The modified combination of anterolateral and lateral approach used by the authors facilitated release of contracture of the soft tissue anterior to the hip joint and correction of flexsion deformity of the hip. In case of multiple joint involvement, the surgery should be performed on the most severely involved one and the next surgery, if required, should be scheduled later within 3 to 6 months.