Angulated Salter osteotomy in the treatment of developmental dysplasia of the hip.

OBJECTIVES Salter osteotomy is widely used to improve acetabular coverage in the treatment of developmental dysplasia of the hip. Herein we describe angulated Salter osteotomy (ASO) as the modified Salter osteotomy, which creates a two-point contact between the proximal and distal fragments and better stabilizes the fixation of the fragments. We reported our results of ASO and compared it with that of Salter osteotomy performed previously by us. METHODS We retrospectively reviewed 41 unilateral hips that underwent ASO, with no other accompanying procedures, between 2012 and 2018. We investigated the radiographic measurements included the preoperative values of the acetabular index and center-edge angle (CEA), immediate postoperative values of distance d (lateral displacement of the distal fragment), lateral rotation angle (LRA), the ratio of the obturator height (ROH), pelvic height increase percentage (PHIP) and the values of acetabular index and CEA during the last follow-up. Measurements were compared with 20 unilateral hips that underwent Salter osteotomy. RESULTS The mean age at the time of surgery was 5.4 years, and the mean follow-up duration was 3.3 years. Immediately after surgery, the mean distance d, LRA, ROH and PHIP were 8 mm, 19°, 70 and 1%, respectively. The last follow-up values of acetabular index and CEA significantly improved from the preoperative values by 18° and 21°, respectively. Patients treated with ASO showed significantly larger distance d, more improvement in CEA, and lesser PHIP than those treated with Salter osteotomy. CONCLUSIONS The short-term outcomes of ASO are favorable. ASO was as effective as or better than Salter osteotomy in pulling out and stabilizing the distal fragment anterolaterally. ASO prevents elongation of the ilium, which causes pelvic obliquity.