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 eleven 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.

Objective: To compare concussion knowledge between US born and internationally born collegiate student-athletes. Furthermore, to investigate whether length of time in the United States impacted concussion knowledge. Design: Survey. Setting: Preparticipation physicals at a midwestern NAIA college. Participants: Three hundred one collegiate student-athletes. Interventions: Demographic questionnaire and the Rosenbaum Concussion Knowledge and Attitudes Survey (RoCKAS). Main Outcome Measures: t test was used to determine whether a difference in Concussion Knowledge Index (CKI) scores exists between US born and internationally born student-athletes. A one-way analysis of variance was used to determine significance for length of time in the United States. Results: A statistically significant difference was found for CKI scores between US born (19.22 ± 2.38) and internationally born student-athletes (18.01 ± 2.57) (t = 3.895, P = 0.000). Analysis of variance demonstrated statistically significant difference for CKI scores (F 2,300 = 13.883, P = 0.001). Post hoc analysis found significant differences in CKI scores between US born (19.22 ± 2.38) and internationally born student-athletes in the United States less than 2 years (17.31 ± 2.52) (P = 0.000), and between internationally born student-athletes in the United States 2 or more years (19.15 ± 2.25) and internationally born student-athletes in the United States less than 2 years (17.31 ± 2.52) (P = 0.002). Conclusion: Among this sample, being born in the United States and length of time in the United States contribute to student-athletes' concussion knowledge. Clinical Relevance: Standardized guidelines are needed to assist health care professionals in properly educating student-athletes about concussions as the recognition and management of concussions can be affected by a student-athlete's knowledge.

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