Slipped capital femoral epiphysis (SCFE) is a multifactorial disorder in which both mechanical and biological factors contribute to physeal instability. Although reduced acetabular anteversion has been suggested to predispose to SCFE, its potential influence on slip severity remains poorly understood.

Decreased acetabular anteversion is independently associated with increasing SCFE severity.

A retrospective single-center study was conducted including all consecutive pediatric patients surgically treated for SCFE between January 2014 and March 2026. Demographic, clinical, and radiographic data were collected. Acetabular version was measured on standardized postoperative low-dose pelvic CT scans. Slip severity was classified according to the Southwick angle as mild (<30°), moderate (30°–50°), or severe (>50°). Comparisons among severity groups were performed using one-way ANOVA or Kruskal–Wallis tests for continuous variables and Pearson's chi-square test for categorical variables. Factors associated with increasing slip severity were evaluated using univariate and multivariable ordinal logistic regression analyses. Results were expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs).

A total of 126 patients (141 hips) were included. Thirty-nine hips (28%) were classified as mild, 55 (39%) as moderate, and 47 (33%) as severe. Mean acetabular anteversion progressively decreased with increasing slip severity (11.7°, 10.0°, and 8.6°, respectively; p = 0.001). No significant differences were observed between severity groups regarding age, sex, body mass index (BMI), bilaterality, chronology of presentation, or triradiate cartilage status. In univariate analysis, decreased acetabular anteversion was significantly associated with increasing slip severity (OR 0.87, p < 0.001). After adjustment for age, BMI, chronology, and bilaterality, acetabular anteversion remained independently associated with increasing severity (adjusted OR 0.80, 95% CI 0.70–0.91; p < 0.001). BMI was also retained in the multivariable model, whereas the remaining variables were not independently associated with slip severity.

This study demonstrates that decreased acetabular anteversion is independently associated with increasing SCFE severity, supporting the hypothesis that acetabular morphology contributes not only to disease susceptibility but also to the progression of physeal displacement. By preserving the full spectrum of Southwick severity through ordinal logistic regression, this study provides a more comprehensive assessment than binary approaches. These findings improve the understanding of anatomical factors associated with SCFE severity and warrant confirmation in prospective multicenter studies including asymptomatic controls.

III; Retrospective cohort study.