Bicycle-Related Acetabular Fractures Are Associated with Anterior Column Involvement: A Multicenter Study with an...

Background/Objectives: Cycling-related acetabular fractures have not been well described. We aimed to determine the proportion of acetabular fractures associated with bicycle accidents and to compare their fracture patterns with those caused by other mechanisms. Findings related to clipless pedal use were considered exploratory. Methods: Patients treated for an acetabular fracture between January 2010 and December 2023 were identified by ICD-10 codes from a university hospital network Clinical Data Warehouse. After exclusions, 378 patients with 385 fractures were classified according to the Judet-Letournel system. Fracture-pattern proportions were compared using Fisher's exact test, and the association with anterior column involvement was examined with logistic regression adjusted for age and sex. Cleat-shoe status, obtained from medical records or telephone interviews, was analyzed descriptively. Results: Bicycle accidents were the mechanism of injury in 26 of 378 patients (6.9%). Compared with fractures caused by other mechanisms, bicycle-related fractures showed a higher proportion of pure anterior column fractures (38.5% versus 16.7%, p = 0.014) and anterior column involvement (65.4% versus 38.2%, p = 0.011). The association with anterior column involvement remained after adjustment for age and sex (adjusted odds ratio 3.02, 95% CI 1.31-6.98). Among 12 confirmed cleat-shoe users, 7 (58.3%) had a pure anterior column fracture, 10 (83.3%) had anterior column involvement, and 8 (66.7%) had extension into the acetabular roof. Conclusions: Bicycle-related acetabular fractures were associated with a higher proportion of anterior column involvement, and the association remained after adjustment for age and sex. Because bone quality and injury energy could not be adjusted for, this association should not be interpreted as causal. The anterior-dominant pattern among confirmed cleat-shoe users is exploratory and should not be interpreted causally.