Treatment of developmental dysplasia of the hip (DDH) between the age of 18 and 24 months.

BACKGROUND: Treatment of developmental dysplasia of the hip between the age of 6 and 18 months starts with closed reduction (CR). If CR is not attainable, open reduction is performed. Open reduction and pelvic osteotomy (ORPO) is usually done directly after the age of two. The aim of this study is to evaluate CR compared to ORPO with respect to early radiographic outcome in patients aged 18 to 24 months at reduction.
METHODS: A single-surgeon cohort was reviewed. Inclusion criteria were age between 18 and 24 months, no prior treatment and minimal follow-up of 2 years. Hips that were not displaced or had a nonidiopathic cause were excluded. Residual dysplasia was defined as a center edge angle (CEA) of less than 15° or CEA less than 20° with an acetabular index (AI) of more than 30°. Multiple regression was used, the outcome was follow-up CEA, and the explanatory variables were age, sex, type of surgery, international hip dysplasia grade and preoperative AI. Values of preoperative AI in the CR group and follow-up CEA were plotted.
RESULTS: Eighty-two hips in fifty patients were included. Residual dysplasia was identified in 16 hips (20%), 12 (27%) after CR, and 4 (11%) after ORPO (p = 0.10). Recurrence and avascular necrosis rates were not statistically different. Preoperative AI and type of surgery independently affected CEA. CR patients with a preoperative AI of more the 40° had a 50% (10/20) risk of residual dysplasia.
CONCLUSION: CR is an important option to consider in selected patients between the age of 18 and 24 months and the selection should not be based on intraoperative assessment only, but also on preoperative measurement of AI. LEVEL OF EVIDENCE: Level III.