Concomitant Open Reduction Does Not Improve Outcomes in Patients Undergoing Osseous Reconstruction for Severe Hip Dysplasia Secondary to Cerebral Palsy: A Radiographic and Clinical Comparative Analysis

Background: Varus derotational osteotomy (VDRO) is frequently combined with pelvic osteotomy and open reduction to treat severe hip subluxation in children with cerebral palsy (CP). The purpose of this study was to compare outcomes of osseous hip reconstruction with and without open reduction in children with CP treated for severe hip subluxation or dislocation. Methods: This was a retrospective review of patients with CP and severe subluxation/dislocation [preoperative migration percentage (MP) ≥60%], who underwent VDRO with or without open reduction at 2 academic institutions between 2017 and 2023. Demographics, Gross Motor Function Classification System (GMFCS) level, key comorbidities, radiographic measurements, operative characteristics, and complications were collected. Statistical methods included descriptive analyses, the Mann-Whitney U test, a generalized linear mixed model, the Pearson χ 2 , and the Fisher exact test, with significance set at P <0.05. Results: A total of 108 hips (88 patients) were included; 30 underwent open reduction (group A), and 78 did not (group B). Mean age at surgery (8.9 vs. 7.5 y, P =0.17) and GMFCS distribution ( P =0.29) were similar. Group A had increased preoperative MP (86% vs. 77%, P =0.004), rate of overall comorbidity burden (100% vs. 79%, P =0.01), operative time (431.9 vs. 362.1 min, P <0.001), estimated blood loss (258.5 vs. 192.6 mL, P =0.03), rate of 90-day medical complications (47% vs. 22%, P =0.01), and rate of secondary surgery (17% vs. 1%, P =0.01) compared with group B. The number of pelvic osteotomies (1.1 vs. 1.3, P =0.23), rate of bilateral procedures (93% vs. 94%, P =1.0), rate of surgical complications (20% vs. 6%, P =0.07), final mean MP (21% vs. 15%, P =0.187), and the proportion of hips with a final MP ≥40% (14% vs. 9%, P =0.48) were comparable between groups. Conclusions: In patients with CP and severe hip subluxation, the addition of an open reduction is associated with longer operative time, increased blood loss, and higher complication/revision rates without demonstrable improvement in radiographic outcomes. These findings do not support the routine inclusion of open reduction as part of osseous hip reconstruction for severe CP-associated hip dysplasia. Level of Evidence: Level III.