Varus derotation osteotomy for the treatment of hip subluxation and dislocation in cerebral palsy: statistical...

The purpose of this study is to review the results of varus osteotomy in patients with cerebral palsy and to determine factors that influence the rates of residual hip displacement. A retrospective chart review of 65 patients who underwent 79 varus osteotomies was performed. Preoperative, postoperative and follow-up radiographs were analyzed for routine radiographic measurements, pelvic obliquity, osteonecrosis (avascular necrosis), joint incongruity or degenerative joint disease. The average follow-up was 5.2 years (range, 1.1-18.4 years). At follow-up, 3 hips were dislocated, 19 were subluxated and 57 were stable (72%). Age at surgery and the degree of preoperative hip displacement had significant effects on outcome. The average age at surgery for initially subluxated hips, which were located at follow-up, was 7.2 years. This was significantly younger (P = 0.008) than initially subluxated hips, which were displaced (10 years of age). Subluxated hips at surgery were also more likely to be located at follow-up than dislocated hips.