ACL deficient knee with medial meniscal tear


Chronic anterior cruciate ligament (ACL) ruptures can be missed on MRI because recognizing an absent structure is harder than recognizing an abnormal structure, particularly when there is scarring along the expected course of the ACL and lack of edema. ACL deficient knees can lead to chronic instability and subsequent meniscal injuries (medial >>> lateral) after 6 months and chondral lesions after 12 months.