Anterior cruciate ligament (ACL) tears rarely happen in isolation. A significant number of patients who tear their ACL also injure the medial collateral ligament (MCL) — usually from the same twisting or valgus (knock-knee) force that damaged the ACL in the first place. Understanding how these two injuries interact is essential for getting the treatment sequence right, because managing a combined ACL-MCL injury is not simply "fix both ligaments at once."

For certain patients (particularly young athletes, those with high-grade pivot shift, or those with specific anatomical risk factors) a technique called lateral extra-articular tenodesis (LEAT) is increasingly being used alongside standard ACL reconstruction to improve outcomes.