J Pediatr Orthop. 2026 Mar 26. doi: 10.1097/BPO.0000000000003269. Online ahead of print.
ABSTRACT
BACKGROUND: Previous studies have evaluated risk factors of residual acetabular dysplasia (RAD) following closed reduction (CR). However, none of them have focused on the association between the age at fusion of the ischiopubic synchondrosis and RAD. The objective of this study was to determine whether the age at fusion of the ischiopubic synchondrosis was associated with RAD after CR and to evaluate other predictors for RAD.
METHODS: We retrospectively reviewed children who underwent closed reduction for developmental dysplasia of the hip (DDH) between 2008 and 2018 and were followed for at least 5 years. Exclusion criteria included inadequate follow-up, a diagnosis of teratologic hip dislocation or the presence of other neuromusculoskeletal diseases, and inadequate radiographs and clinical records. RAD was defined as a Severin classification grade of3 at last follow-up or having undergone a secondary reconstructive surgery. The AP pelvis plain radiograph was used to identify the age at fusion of the ischiopubic synchondrosis, IHDI grade, avascular necrosis (AVN), and to measure the acetabular index (AI). Statistical analysis was performed.
RESULTS: A total of 150 children (187 hips) with an average age of 13.6 months (range: 4 to 22 mo) at closed reduction were included. For an average duration of 7.6±2.1 years (range: 5 to 14 y) of follow-up, 53 (28.3%) hips were classified in Severin grade 3/4, and 73 (39%) hips underwent a secondary procedure. There was a significant difference in AI pre-CR and post-CR between the non-RAD and RAD groups. Analysis of the groups showed that the RAD group had a higher IHDI grade than the non-RAD group (P<0.01). The incidence of RAD was significantly higher in children with ischiopubic synchondrosis fused younger than 5 years compared with those with ischiopubic synchondrosis fused 5 years and older (82.9% vs. 63.2%, respectively; P=0.02). The mean AI declined after a reduction in both groups, with the greatest fall occurring in the first year. Cutoff values of AI were 30 degrees at 1 year and 27 degrees at 2 to 3 years post-CR.
CONCLUSION: In patients with CR of DDH, higher IHDI grade and larger AI pre-CR were associated with increased RAD. Age at fusion of the ischiopubic synchondrosis is a predictor for RAD. The acetabulum continued to remodel for 5 years after CR, suggesting long-term observation to identify acetabular dysplasia.
PMID:41884888 | DOI:10.1097/BPO.0000000000003269
