Unhappy Triad

High Quality Content by WIKIPEDIA articles! An unhappy triad (or terrible triad, horrible triangle, O'Donoghue's triad or a blown knee) is an injury to the anterior cruciate ligament, medial collateral ligament, and the meniscus. The triad refers to a complete or partial tear of the anterior cruciate ligament, medial collateral ligament, and the meniscus. Originally the unhappy triad included the medial meniscus and not the lateral meniscus. However, during the 1990's, analysis indicated that the 'classic' O'Donoghue triad is actually an unusual clinical entity among athletes with knee injuries. In this type of injury, acute tears of the medial meniscus always present with a concomitant lateral meniscus injury. However, the lateral meniscus tears are far more common than medial meniscus tears in sprains of the ACL.