Outcome of Closed Reduction in Developmental Dysplasia of Hip Joint- A Single-Center Retrospective Study

Background: Developmental dysplasia of the hip (DDH) is a disorder of abnormal development of the hip joint resulting in dysplasia, subluxation or dislocation. Treatment varies from abduction splinting/bracing to surgical reduction and osteotomies depending on patients age and the degree of dysplasia. For the last decades, treatment by closed reduction combined with earlier diagnosis has become the desired and widely accepted approach. These treatment options occasionally result in considerable hip problems like re-dislocation, avascular necrosis and stiffness. There are some good studies done globally but still no studies done in our setting regarding the outcome of closed reduction for the treatment of DDH. Objectives: The aim of this study is to evaluate the outcome of closed reduction in-patient with DDH among Omani population who had attended Armed Force Hospital, Muscat in the period between 2010-2020. Expected outcome: Successful outcome following closed reduction is high and the incidence of complications is low. International Institute of Hip Dysplasia (IHDI) classification is a reliable predictive tool for the success of closed reduction in patient with DDH and related to better scores in Mckay criteria as well as Severin classification. Methodology: In this study, we retrospectively evaluated (36) hips of children, who were diagnosed with DDH and then underwent closed reduction and hip spica cast immobilization followed by abduction splint. We reviewed the success rate and possible complications over the last 10 years. At each follow up, they were assessed clinically and radiographically for redislocation, AVN and stiffness. Last clinical examination was evaluated using Mckay criteria and radiographic imaging was evaluated using Severin classification and osteonecrosis was assessed using Kalamchi score. All children who had DDH as a part of their connective tissue disorder/syndrome or lost to follow up were excluded from the sample of the study. Results: Most patients had unilateral DDH. Only 28% of patients had bilateral DDH. The proportion of hips with a pre-reduction IHDI grade I, II, III, and IV were 8%, 47%, 36% and 8%, respectively. The mean age at the time of closed reduction was 8+/- 4.5 months (range 3- 20 months). Clinical assessment in the last follow up showed that 81% of hips had excellent outcome, 3% of hips had poor outcome and 17% of hips had treatment failure according to the Mckay scoring system. Radiographic analysis demonstrated that 27.8% had excellent outcome (Severin Class I), 19.4 % had good outcome (Severin Class II), 33.3 % had fair outcome (Severin Class III), and 19.5% had poor results (Severin Class IV to VI). A significantly higher incidence of re-dislocation was observed in IHDI grade III and IV. The treatment failure was almost 16.6%. 50% of failed cases had underwent a trial Pavlick harness treatment. Kalamchi and MackEwen score has been used to grade avascular necrosis (AVN). However, no one in the study has developed AVN or stiffness. Conclusion: Our study had an 83.3% success rate. 16.7% was the failure rate. Non of them developed radiographic AVN or stiffness. Pre- reduction IHDH grade IV is highly associated with closed reduction failure. Prior treatment of Pavlick harness is not a determinant factor for failure of closed reduction.