Femoral osteotomy is not recommended for children aged 2-3 years with Tönnis grade III developmental dysplasia of the hip.

The objective of this study was to compare outcomes following open reduction with and without femoral shortening when treating patients aged 2-3 years with Tönnis grade III developmental dysplasia of the hip (DDH). In this prospective study, 78 patients (6 boys and 72 girls; mean age: 27.8 months; age range: 24-35 months) with Tönnis grade III DDH at our hospital from January 2014 to August 2017 were included. There were 34 hips in the without femoral shortening group and 44 hips in the femoral shortening group. Clinical outcomes were rated using the modified McKay criteria, and the hips were graded using the Severin score. Avascular necrosis (AVN) and redislocation were assessed. Mean follow-up was 26.5 months (range 17-32 months). In the without femoral shortening group (n = 34), there were five patients with AVN (14.7%), and 30 scored excellent and 4 scored good results per the modified McKay criteria. Further, 28 excellent and six good results were obtained using the Severin scale; no patient had redislocation. In the femoral shortening group(n = 44), there were seven patients with AVN (15.9%), and 38 scored excellent and six scored good results per the modified McKay criteria. Further, 31 excellent and 13 good results were obtained using the Severin scale; no patient had redislocation. Additionally, there were no statistically significant differences based on Modified McKay criteria, Severin score and AVN rate. Femoral shortening is not required for children aged 2-3 years with Tönnis grade III DDH.