Association of Compartmental Bone Bruise Distribution With Concomitant Intra-articular and Extra-articular Injuries in Acute Anterior Cruciate Ligament Tears After Noncontact Sports Trauma

BACKGROUND: Anterior cruciate ligament (ACL) injuries are frequently associated with bone bruises, and their presence may be associated with concomitant intra- and extra-articular injuries. PURPOSE: To investigate the prevalence and pattern of distribution of bone bruises in patients with acute ACL tears from noncontact sports trauma and their association with specific intra- and extra-articular injuries. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 168 patients underwent magnetic resonance imaging (MRI) within 6 weeks of sustaining an ACL tear. Information regarding their demographics as well as MRI evidence of bone bruise patterns and associated injuries was carefully documented. Univariate and multivariate logistic regression analyses were performed to determine the association between bone bruises and concomitant intra- and extra-articular injuries seen on MRI. RESULTS: Bone bruises were observed in 155 (92.3%) of 168 patients. The prevalence of bone bruises was 83.9%, 78.6%, 56.5%, and 29.8% on the lateral tibial plateau, lateral femoral condyle, medial tibial plateau, and medial femoral condyle, respectively. A total of 110 (65.5%) patients had bone bruises in both the medial and lateral compartments of the knee, 41 (24.4%) had isolated lateral compartment bone bruises, 4 (2.4%) had isolated medial compartment bone bruises, and 13 (7.7%) did not have any bone bruises. None of the demographic factors were significantly associated with the presence or absence of bone bruises. The presence of bone bruises was significantly associated with lateral meniscal injuries (P = .05). Lateral compartment bone bruises were significantly associated with lateral meniscal injuries (P = .034), while bone bruises affecting both the lateral and medial compartments were significantly associated with medial collateral ligament (MCL) injuries (P = .044) and lateral collateral ligament (LCL) injuries (P = .038) in addition to lateral meniscal injuries (P = .022). CONCLUSION: Bone bruises are common in patients with acute ACL tears after noncontact sports injuries. The compartmental distribution of bone bruises is associated with concomitant intra- and extra-articular injuries. Bone bruises involving the lateral compartment of the knee are associated with lateral meniscal injuries, while bone bruises involving both the lateral and medial compartments of the knee are associated with MCL and LCL injuries in addition to lateral meniscal injuries.