Abstract: To explore the effect of total hip arthroplasty (THA) in patients with ankylosing spondylitis (AS). Methods9 patients with AS underwent total hip arthroplasty on both lateral hips at the same time with a lateral incision（bone cement prosthesis was used in 2 patients and no cement prosthesis in 7 patients）, after the operations they received systemic healing exercises and were followed up for 6 to 26 (mean 18) months. The Harris grade system and Xray examination were used to evaluate the curative effects. ResultsThe postoperational movement range was significantly improved, and all of the flexion deformities were nearly rectified. According to their X-rays, there were also no dislocations, aseptic loosening or fractures of the prosthesis. The recent Harris hip scores of these patients after THA were 59 to 90 and the average scores was 76.4. ConclusionTHA is effective in treating patients with ankylosing spondylitis.

Key words: Total hip arthroplasty, Ankylosing spondylitis, Rigidity of hip joint