Mid-term Results Following Surgical Hip Dislocation for Residual Pediatric Deformities

Background: Mid-term results following surgical hip dislocation (SHD) for healed slipped capital femoral epiphysis (SCFE) and Perthes-related deformities are limited. This study aimed to characterize patient-reported outcome measures [including rates of achieving the minimal clinically important difference (MCID) and patient-acceptable symptomatic state (PASS)], report survivorship free from conversion to arthroplasty, and identify risk factors associated with composite failure. Methods: Twenty-seven patients (n=13 SCFE, n=14 Perthes) with minimum 2-year follow-up (mean 5.7 y) who underwent primary SHD from 2011 to 2021 were retrospectively reviewed. Modified Harris Hip Score (mHHS) and International Hip Outcome Tool-12 (iHOT-12) were collected preoperatively and at the latest follow-up. Composite failure was defined as not meeting any MCID/PASS threshold or conversion to arthroplasty. Continuous variables were analyzed using independent-sample t tests or the Wilcoxon Mann-Whitney test, where appropriate. Categorical variables were analyzed using chi 2 or Fisher exact test, as indicated. Kaplan-Meier survivorship was determined. Results: Mean mHHS improved from 56.2 to 77.2 (P=0.003) and from 63.0 to 86.3 (P<0.001), while iHOT-12 improved from 36.1 to 64.7 (P=0.008) and 36.8 to 77.2 (P<0.001) in SCFE and Perthes cohorts, respectively. MCID achievement for mHHS and iHOT-12 were 85.7% and 75.0% among SCFE, compared with 83.3% and 81.8% in Perthes. The proportion meeting PASS for mHHS and iHOT-12 was 30% for both in SCFE, compared with 61.5% and 83.3% in Perthes. 5- and 10-year survivorship free of conversion to arthroplasty was 100% and 80%, as well as 93% and 77% in the SCFE and Perthes cohorts, respectively. Conclusions: At mid-term follow-up, patients undergoing SHD for residual deformities related to chronic SCFE and Perthes demonstrated significant improvements in mHHS and iHOT-12, as well as relatively high rates of meeting MCID. SHD is an effective approach providing pain and functional benefit. Preoperative expectations, though, should be tempered in these cohorts, as some pre-existing damage limits the ability to completely normalize anatomy. Level of Evidence:Level III, retrospective comparative study.