Prevalence and location of bone bruises associated with anterior cruciate ligament injury and implications for mechanism of injury: a systematic review.

Background: Bone bruising is commonly observed on magnetic resonance imaging (MRI) after non-contact anterior cruciate ligament (ACL) injury.
Objectives: The primary objective of this study was to determine if the location and prevalence of tibial and femoral bone bruises after ACL injury can be explained by specific injury mechanism(s). The secondary objective was to determine whether the bone-bruise literature supports sex-specific injury mechanism(s). We hypothesized that most studies would report bone bruising in the lateral femoral condyle (LFC) and on the posterior lateral tibial plateau (LTP).
Methods: MEDLINE, PubMed, and SCOPUS were searched for studies that reported bone bruise prevalence and location in ACL-injured subjects. Sex differences in bone-bruise patterns were assessed. Time from injury to imaging was assessed to account for confounding effects on bone-bruise size and location.
Results: Thirty-eight studies met the inclusion/exclusion criteria. Anterior-posterior location of bone bruises within the tibiofemoral compartment was assessed in 11 studies. Only five of these studies reported bone-bruise locations on both the tibia and the femur. The most common bone-bruise combination in all five studies was on the LFC and the posterior LTP. Sex differences were only assessed in three studies, and only one reported significantly greater prevalence of LTP bruising in females.
Conclusion: Bone-bruise patterns in the current literature support a valgus-driven ACL injury mechanism; however, more studies should report the specific locations of tibial and femoral bone bruises. There is insufficient evidence in the literature to determine whether there are sex-specific bone-bruise patterns in ACL-injured subjects.