We report bone bruises on Anterior Cruciate Ligament (hereinafter referred to as ACL) injury. We also investigated the relationship among the presence or absence of bone bruises, localization, and the presence or absence of meniscal injury according to the period of MRI scan from injury.

We underwent the study used a total of 76 knees who underwent ACL reconstruction at our hospital and related hospitals from January 2014 to December 2017. We investigated on MRI images taken after injury. Meniscal injuries were evaluated by intraoperative findings.

The average age at injury was 25.8 years old (13–48 years old) in 44 males and 32 females. Bone bruises were found in 54 of 76 knees (71%). Among them, the ratio of non-contact type was much higher in the group with bone bruises than in the contact group (83% in the group with bone bruises, 64% in the group without bone bruises), resulting in a shorter period from injury to MRI (bone bruises group: 12.4 days, non-bone bruises group: 23 days). Looking at the appearance frequency of bone bruises according to the period from injury to MRI imaging, the appearance frequency of bone bruises decreased as the time to imaging became longer (within 2 weeks of injury: 76%, injury from 2 weeks to 1 month: 65%, injury 1–3 months: 53%). With regard to the localization of bone bruises, in the coronal section, both femurs and tibiae frequently had bone bruises on the outside. In the sagittal section, it occurred in front of the femur, in particular. On the tibial side, many cases of bone bruises occurred in the rear. In addition, the association between bone bruises and meniscal injuries were significantly complicated with lateral meniscal injury in the group without femoroconstriction in the group with lateral femoral bone bruises and in the group with posterior tibia bone bruises. There was no significant association between bone bruises and meniscal injury among the other groups.

Bone bruises were found in 54 of 76 knees (71%). Regarding the occurrence of many lateral developments, it is thought that the tibia is sub-dislocated anteriorly due to mild flexion, valgus force, and external rotation injury, and injury is caused by axial pressure applied to the outside of the femur and posterior of the tibia It was done. As a result, it was considered that the external meniscal injury was injured. The medial unilateral development of bone contusion was observed in 3 knees on the medial femur and 1 knee on the medial tibia. All internal single-cased cases are contact-type injuries, the result of which may be different in the mechanism of bone contusion development.