Proposal of a New Type of Innominate Osteotomy without the Use of Bone Graft in Children: A Preliminary Study

Good long-term outcomes have been reported for the Salter innominate osteotomy (SIO), which is widely used to correct developmental dysplasia of the hip (DDH) in children. In this study, we describe the procedure and early outcomes of a new pelvic osteotomy termed “angulated innominate osteotomy” (AIO). METHODS: Twenty-one patients (22 hips) underwent AIO. We evaluated age at the time of surgery, operative time, blood loss, and time to bone union. Several radiographic parameters were assessed preoperatively, immediately postoperatively, and at the time of the latest examination. Measurements were compared with those of 20 previous patients who underwent SIO. The AIO is made to form an isosceles triangle. This enables 2 points of contact between the proximal and distal bone fragments, eliminating the need for a bone graft. RESULTS: Mean age at the time of surgery was 5.9 years, and the mean duration of follow-up was 30.8 months. The mean operative time was 103 minutes, mean blood loss was 33 mL, and mean time to bone union was 9.8 weeks. Immediately postoperatively, the mean “distance d” (lateral displacement of the distal fragment), mean ratio of the obturator heights (ROH), and mean lateral rotation angle (LRA) were 7.2 mm, 70.4%, and 19.3°, respectively. At the latest examination, the mean acetabular index (AI), center-edge angle (CEA), and acetabular head index (AHI) were 16.4°, 23.7°, and 85.5%, respectively, each of which were significantly improved compared with the preoperative values. Moreover, the mean postoperative iliac length difference (ILD) between the operative and contralateral sides was only 0.1 mm. Those treated with AIO had a significantly shorter operative time and time to bone union, and less blood loss, than those treated with SIO. The mean distance d, ROH, and LRA did not differ significantly from SIO results, while the mean ILD was significantly less. CONCLUSIONS: AIO is a less-invasive procedure that does not require a bone graft, and the short-term outcomes were favorable. Sufficient coverage of the acetabulum with displacement of the distal bone fragment to an extent similar to SIO can be achieved; we consider AIO a worthy surgical procedure that has the potential to provide good long-term outcomes similar to those seen with SIO. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.