The association of bone bruising and grade of MCL injury in patients sustaining isolated MCL injuries.

Abstract

To investigate the incidence of bone bruising with isolated medial collateral ligament injury and to assess whether the presence of bone bruising is related to the injury grade. Patients who sustained an acute isolated medial collateral ligament injury demonstrated on knee MRI between 2016 and 2020 were included in this study. Patient's characteristics and injury classification (clinical and radiological) were reviewed from clinical notes and imaging. The patients were divided into two groups, based on the presence of bone bruising. Fisher's exact test was used for dichotomous variables and odds ratios were computed in areas of clinical significance. Sixty patients with a median age of 37.6 ± 13.8 were included. Twenty-eight (46.7%) had bone bruising demonstrated on MRI scan. The bone bruising group were 7 times (95% CI [1.4;36.5]) more likely to have a complete disruption of the superficial medial collateral ligament and MRI grade III injury. Injury to the deep medial collateral ligament was more often observed in this group (p < 0.05). The most common location of bone bruising was the lateral femoral condyle (57.1%, 16/28) and/or the medial femoral condyle (57.1%, 16/28). The incidence of bone bruising with isolated medial collateral ligament injury is significant and is more common with radiologically higher grade injuries. There was no statistically significant difference between the anatomical location of bone bruise and the grade of MCL injury. Bone bruising patterns can help determine the mechanism of injury, with a valgus impact or avulsion type injury most commonly seen.