Twenty-three patients with ankylosing spondylitis underwent thirty-four
total hip arthroplasties with an average follow-up of 42.5 months. The
over-all results were rated good in all but two patients. Significant
benefit was obtained in posture and function so that these patients could
be gainfully employed. Improvement in the sum total range of motion was
96.1 degrees in patients with bone ankylosis and 150 degrees in those with
fibrous ankylosis. The preoperative sum total range of motion was
maintained or improved in hips with a painful arc of motion. Most of the
limited motion in patients with ankylosed hips was due to myositis
ossificans.