Long-term Outcomes of Cemented Total Hip Arthroplasty in Patients with Ankylosing Spondylitis at a Minimum Follow-up of 10 Years.

Purpose: This study was performed to evaluate long-term clinical and radiologic outcomes of cemented total hip arthroplasty in patients with ankylosing spondylitis.

Materials and Methods: A retrospective study of 12 patients (16 cases) diagnosed with ankylosing spondylitis undergoing total hip arthroplasty with cemented femoral stem from November 2002 to January 2006 with a minimum follow up of 10 years. Clinical outcomes were assessed using Harris Hip Scores and measures of pain and range of motion. Radiologic outcomes were assessed with serial plain X-ray. Fixation and stability of implant, enthesopathy of ischium and development of heterotopic ossification were also evaluated.

Results: Mean Harris Hip Scores significantly improved from pre-operative levels (58 points; range, 39-81 points) to post-operative (92 points; range, 68-100 points). Mean flexion contracture levels decreased from preoperative (13°) to post-operative (5°), and mean post-operative range of motion improved 106° compared to preoperative levels. No newly developed osteolysis lesions or implant loosening were observed in last follow up X-rays. One heterotopic ossification and one greater trochanter fracture were observed. Greater trochanter fracture was treated conservatively, and was resulted in bony union. No patients underwent revisions.

Conclusion: This study revealed positive long-term clinical and radiologic outcomes following total hip arthroplasty with cemented femoral stems in patients with ankylosing spondylitis patients.