Few studies have examined the order in which a spinal osteotomy and total hip replacement (THR) are to be performed for patients with ankylosing spondylitis. We have retrospectively reviewed 28 consecutive patients with ankylosing spondylitis who underwent both a spinal osteotomy and a THR from September 2004 to November 2012. In the cohort 22 patients had a spinal osteotomy before a THR (group 1), and six patients had a THR before a spinal osteotomy (group 2). The mean duration of follow-up was 3.5 years (2 to 9). The spinal sagittal Cobb angle of the vertebral osteotomy segment was corrected from a pre-operative kyphosis angle of 32.4 (SD 15.5°) to a post-operative lordosis 29.6 (SD 11.2°) (p < 0.001). Significant improvements in pain, function and range of movement were observed following THR. In group 2, two of six patients had an early anterior dislocation. The spinal osteotomy was performed two weeks after the THR. At follow-up, no hip has required revision in either group. Although this non-comparative study only involved a small number of patients, given our experience, we believe a spinal osteotomy should be performed prior to a THR, unless the deformity is so severe that the procedure cannot be performed.

Cite this article: Bone Joint J 2014;96-B:360–5.

Fifteen patients with ankylosing spondylitis who had developed a severe flexion deformity of the cervical spine which restricted their field of vision to their feet, were treated by an extension osteotomy at the C7/T1 level. The operation was performed under general anaesthesia with the patient in the prone position and wearing a halo-jacket. Three had internal fixation using a Luque rectangle and wiring. Their mean age was 48 years. Before operation the mean cervical kyphosis was 23°; this was corrected to a mean of 31° of lordosis, a mean correction of 54°. All the patients were able to see straight ahead. One patient with normal neurology soon after operation became quadraparetic after one week; two others had unilateral palsy of the C8 root, which improved. There was subluxation at the site of osteotomy in four patients, and two of them developed a pseudarthrosis which required an anterior fusion