Abstract
In 1950 O'Donoghue called attention to “that unhappy triad which comprised (1) rupture of the medial collateral ligament, (2) damage to the medial meniscus, and (3) rupture of the anterior cruciate ligament” and recommended early surgical intervention.
Ten patients with arthroscopically confirmed acute (<1 month) tears of the medial collateral ligament (MCL) and anterior cruciate ligament (ACL) were identified. There were 9 men and 1 woman with an average age of 33.4 years (range; 17-52 years).
There was a 50% incidence (5 knees) of lateral meniscal tears. Of these, 1 knee had an associated medial meniscal tear. There were only 2 knees (20%) with medial meniscal tears. Chondral injuries to the lateral compartment were noted in 4 cases. There were 3 knees without meniscal tears and chondral injury.
We conclude that the “unhappy triad” is an unusual clinical entity with knee injuries and may be more accurately described as a triad consisting of ACL, MCL, and lateral meniscus tears.
