San Diego pelvic osteotomy in patients with closed triradiate cartilage

PURPOSE: A San Diego pelvic osteotomy is frequently used as part of the surgical treatment of neuromuscular patients with hip displacement. This short-term follow-up study assesses the effectiveness of this osteotomy in patients with closed triradiate cartilage compared with open triradiates. METHODS: Retrospective review of 43 patients (44 hips) with neuromuscular hip disease who underwent a San Diego pelvic osteotomy to correct hip displacement. In all 24 hips had open triradiate cartilage at the time of surgery and 20 hips were closed. Centre edge angle (CEA), acetabular angle (AA) and Reimer’s index (RI) were recorded from preoperative, postoperative and the latest follow-up radiographs and statistical analysis was performed. RESULTS: CEA improved by 39° (7° to 69°) in the open group and 30° (9° to 80°) in the closed group from preoperative radiographs to postoperative, with no significant difference in improvement between groups (p = 0.084). There was no significant difference in AA between the open (improved by 11° (3° to 23°)) and closed (improved by 10° (4° to 21°)) groups (p = 0.65). RI improved from 61% to 11% in the open group and 51% to 12% in the closed group. There was no statistically significant difference between groups in RI at preoperative, immediate postoperative and final follow-up radiographs. At latest follow-up, CEA, AA and RI all remained relatively stable in both groups. CONCLUSIONS: San Diego pelvic osteotomy is equally effective in improving radiographic parameters in neuromuscular patients with both open and closed triradiate cartilage. This study challenges the notion that closed triradiate cartilage is a contraindication to a San Diego pelvic osteotomy. LEVEL OF EVIDENCE: III