Treatment of developmental hip dysplasia under 24 months by modified anterior open reduction: A short-term follow-up study

Background: Open reduction(OR) through an anterior approach for the treatment of developmental dysplasia of the hip (DDH) in children younger than 24 months of age is a popular method with proven high success rates . The aim of this study is to present the results of open reduction through a modified anterior approach. Methods: : We retrospectively reviewed 60 hips of 45 patients with DDH under 24 months who underwent this modified anterior approach from June 2017 to February 2020. The surgical technique, operative time, intraoperative bloodloss and preoperative Tonnis grade and acetabular index (AI) were recorded in detail. In the latest follow up, the length of the scar, range of motion (ROM), the postoperative AI, centre-edge angle (CEA), Severin radiographic grade and avascular necrosis (AVN) of the femoral head were all assessed. Results: : The average operation time was 25 ± 2.8 minutes in unilateral side and 45 ± 4.5 minutes in bilateral sides, the average intraoperative bloodloss was 10.0 ± 4.2 ml in unilateral side and 25.0 ± 1.3ml in bilateral sides. The mean AI was 35.03 ± 2.18°(range 29-45°) in the preoperative period and 20.68 ± 2.01°(range16-33°) at the final follow-up visit. The mean CEA at the final follow-up visit was 23.15 ± 2.05° (range18-32°). On the basis of the modified McKay classification for functional evaluation of hips, the postoperative excellent and good rate reached 96.6%. According to Severin radiological classification evaluation criteria, the postoperative excellent and good rate also reached 93.3%. Three of the hips that had been operated on showed type I signs of avascular necrosis(AVN) in X-ray. Four hips in three patients underwent secondary revision surgery. Conclusions: : Open reduction through the modified anterior small incision approach was an encouraging and safe option for treating DDH patients younger than 24 months old who need an open reduction-only treatment, especially for patients with bilateral DDH. Bone procedures may be required for those patients with preoperative AI greater than 40° and(or) Tonnis grade IV. Level of evidence: IV, retrospective non-randomized study.