Medial Collateral Ligament Injury in Posterior Cruciate Ligament Tibial Avulsion Fractures

Background: Posterior cruciate ligament tibial avulsion fracture (PCLAF) is relatively rare. This fracture may be accompanied by soft tissue injuries, most commonly involving the medial collateral ligament (MCL). The present study aimed to determine the rate of MCL injury and its association with fracture characteristics in patients with PCLAF. Methods: Patients with PCLAF were identified with computed tomography, and associated ligamentous and meniscal injuries were evaluated with magnetic resonance imaging. Fracture morphology was assessed via heat maps and quantitative measurements. Receiver operating characteristic (ROC) curves and logistic regression analyses were utilized to identify predictors of MCL injury. Results: A total of 148 ethnic Chinese patients with PCLAF were included (mean age, 48.1 ± 12.9 years; 33.1% female), and 28.4% had concomitant MCL injuries. MCL injuries were significantly associated with posterior horn tears of the medial meniscus (p < 0.001). Patients with MCL injuries exhibited a larger fracture distribution area on heat maps. Consistent with that finding, quantitative analysis showed that these patients had a significantly smaller fracture medial border (p < 0.001) and a significantly larger fracture anteroposterior diameter percentage (p < 0.001). Multivariable analysis identified a fracture anteroposterior diameter percentage of ≥50.2% as an independent predictor of MCL injury (odds ratio, 13.74; 95% confidence interval, 4.85 to 38.95; p < 0.001). Conclusions: MCL injury is relatively common in patients with PCLAF and tends to occur concomitantly with a larger avulsed fragment. The fracture anteroposterior diameter percentage may serve as a valuable predictor for identifying concomitant MCL injury. Level of Evidence: Prognostic Level IV . See Instructions for Authors for a complete description of levels of evidence.