The Effect of Proximal Posterior Tibial Slope on the Incidence of Anterior Cruciate Ligament Injury

Abstract

Several studies have investigated the association of posterior tibial slope (PTS) with anterior cruciate ligament (ACL) injury. However, the results have been inconclusive and even contradictory. The first goal of this study was to evaluate the association of PTS with an ACL injury. The second goal was to identify the patients' characteristics that might affect PTS and ACL injury. In a retrospective case-control study, PTS was evaluated in the MRI of the 173 patients with an ACL tear and 136 patients who underwent MRI for other knee injuries. MRI images were analyzed using imaging software (OsiriX). The role of the patient,s characteristics, such as age and gender, in the association of PTS with an ACL injury was also assessed in the ACL tear group. Both medial and lateral PTS were significantly more in the ACL tear group than the ACL intact group (p < 0.001 for both). In patients with an ACL tear, lateral PTS, but not medial PTS, was significantly greater in females and older patients (p = 0.23 and < 0.001 respectively). In multivariate analysis, lateral PTS, older age, female gender, and associated injury were significant risk factors of an ACL tear. Medial PTS was not identified as a significant risk factor of the ACL tear in the multivariate model. Although PTS is a significant predictor of an ACL tear, patients' characteristics such as gender and age could be used further to characterize the association of PTS and ACL injury and identify the subjects at higher risk of ACL injury.