Diagnostic Delay in Slipped Capital Femoral Epiphysis: A Single-Centre Study in Switzerland.

Background/Objectives: Slipped capital femoral epiphysis (SCFE) is frequently diagnosed after substantial delay, which may be associated with greater deformity and more complex treatment. We aim to describe diagnostic delay in a Swiss tertiary-care cohort and examine its associations with radiographic severity and surgical treatment. Methods: We retrospectively reviewed patients younger than 16 years treated for SCFE between 2000 and 2024. Patient-level demographic characteristics were distinguished from hip-level clinical, radiographic, and treatment variables, and hip-level regression models used patient-clustered robust standard errors. Results: The cohort comprised 63 patients and 71 affected hips, including 8 patients with bilateral SCFE. Diagnostic delay was 0-3 weeks for 8 hips (11%), 3-12 weeks for 34 (48%), and >12 weeks for 29 (41%). Mean Southwick angle was 35.7° (SD 19.6) and was greater in the >12-week group. In an exploratory multivariable clustered logistic model adjusted for Southwick angle, age, and surgery year, each additional week of diagnostic delay was associated with higher odds of osteotomy (OR 1.11, 95% CI 1.05-1.17; p < 0.001). The exploratory ROC AUC was 0.903 (patient-cluster bootstrap 95% CI 0.808-0.969). Conclusions: Substantial diagnostic delay was observed in this Swiss tertiary-care cohort and was associated with radiographic severity and surgical treatment. These associations remain observational and should not be interpreted causally.