Does the posterior condylar angle (PCA) affect the risk of an anterior cruciate ligament (ACL) tear? A case-control study in males aged 18-30

Introduction. Injuries of the ACL are the most common ligamentous injuries of the knee joint, highlighting the importance of tools to easily determine the patients from a risk group. Aims. The aims of this study were: to establish whether the posterior condylar angle (PCA) is a risk factor of ACL injury among 18-30 year-old males and to assess the differences in PCA among patients with isolated ACL injury vs. ACL injury combined with acute MCL, or meniscal injury. Methods and materials. A case group was formed, according to a priori power analysis (α = 0.05, β = 0.95), with 44 patients with an ACL injury and a control group with 44 healthy patients. Then, the case group was subdivided into three subgroups: the MCL and meniscal injured. Two lines were drawn on the axial MRI – the posterior condylar axis and the surgical transepicondylar axis. The PCA was defined as the angle between them. Statistical analyses included U Mann-Whitney, t-student independent-sample tests, linear regression models and correlation analyses. Results. The mean PCA in the control and study group was 1.90° ±1.25° and 1.30° ±2.49°(p = 0.178), respectively. Univariate analyses of PCA in isolated ACL injury vs. ACL injury combined with acute MCL, MM or LM injury had p values of 0.981, 0.814 and 0.813, respectively. Multivariable analysis had p values of 0.744, 0.421 and 0.873, respectively. Intrarater ICCs were 0.931 and 0.928 (excellent reliability) and interrater ICCs was 0.868 (good reliability). Conclusions. PCA is not associated with acute ACL injuries in the studied population. MCL or meniscal injuries did not alter PCA values among patients with an ACL injury.