Bone bruise patterns in knee injuries: where are they found?

Purpose Bone bruise represents an entity of occult bone lesions that can occur in the knee, causing knee pain and tenderness clinically. The aim of this study was to investigate the incidence and pattern of bone bruising seen in the anterior cruciate ligament (ACL) injury cohort, the non-ACL injury cohort, and between both cohorts. Methods We reviewed 710 knee magnetic resonance imagings performed over a 6-month period. Eighty-eight patients with prior history of a knee injury were identified. The mechanism of injury and other clinical findings was noted. Results Among these 88 patients, 58 patients had an associated ACL injury (31 had isolated ACL injuries; 27 had combined ACL and other ligamentous injuries). Among the 30 who had non-ACL injuries, 15 had either an MCL, LCL, or PCL injury. The remaining 15 patients had no associated ligament injury. With an ACL injury, the most common bone bruise sites are the lateral femur (74 %) and lateral tibia (64 %). Without an ACL injury, the pattern of bruising was more common in the lateral femur (69 %) and medial tibia (37 %). Conclusion Bone bruises are important as previous studies have shown that they can cause persistent knee pain. Our study has shown that there are differences in pattern of bone bruising in knee injuries with or without ACL injuries.