 Some authors mistakenly believe that in this type of injury, "combined anterior cruciate and medial collateral ligament (ACL- MCL) disruptions that were incurred during athletic endeavors" always present with concomitant medial meniscus injury.However, the 1990 analysis showed that lateral meniscus tears are more common than medial meniscus tears in conjunction with sprains of the ACL.The unhappy triad occurs due to a lateral blow to the knee causing a rupture in the anterior cruciate ligament, medial collateral ligament, and meniscus.