Male Gender and Normal Trochlear Anatomy Are Associated with a Higher Risk of Osteochondral Fracture Following Patellar Dislocation: A Retrospective Review of 261 Skeletally Mature Patients.

Background

Osteochondral fractures (OCFs) following acute patellar dislocation significantly influence treatment decisions and long-term prognosis, yet reliable risk stratification remains elusive. This study aimed to identify demographic and trochlear morphology predictors of fracture occurrence in a large patient cohort.

Methods

This retrospective analysis included 261 skeletally mature patients with acute patellar dislocation from 2000 to 2024 (mean age 24 ± 10 years, 59% male), excluding those with previous knee surgery, additional injuries, or skeletal immaturity. A comprehensive MRI assessment evaluated trochlear morphology (Dejour classification, sulcus angle, trochlear groove depth, and facet measurements) and patellofemoral alignment parameters (TT-TG distance, Q-angle, and congruence angle). Multivariate logistic regression identified independent risk factors for the development of osteochondral fractures.

Results

Osteochondral fractures occurred in 133 patients (51% [of those undergoing MRI evaluation]). Male gender emerged as the strongest predictor (OR 2.38, 95% CI: 1.30-4.42, p = 0.005), followed by right-sided dislocation (OR 2.33, 95% CI: 1.21-4.58, p = 0.013). Notably, higher-grade trochlear dysplasia (Dejour Grades 3-4) was associated with lower fracture rates, being more common in non-fracture patients (27% vs. 10%, p = 0.003). Trochlear condyle asymmetry was also significant (OR 1.14, p = 0.004). Most patellofemoral alignment parameters, including TT-TG distance and Q-angle, showed no significant predictive value.

Conclusions

Male gender and right-sided dislocation are associated with higher rates of osteochondral fracture after patellar dislocation. Patients with normal trochlear anatomy have higher fracture rates than those with severe dysplasia. These findings suggest that demographic factors and trochlear morphology should be considered in the diagnostic workup of acute patellar dislocations, though prospective validation is needed before implementing screening protocols.