Learn about the symptoms, causes, and diagnosis of the unhappy triad
The unhappy triad is the name given to the combination of three ligament injuries in the knee when the ACL, MCL, and meniscus are all completely or partially torn. It was given it’s name in the 1920’s by doctors working on patients who had this combination of injuries. Due to the severity of the injury and the unlucky nature of tearing all three ligaments, they named the injury the unhappy triad. It is also often called the terrible triad or O’Donaghues triad as well.
Although there is no exact formula for what causes an unhappy triad and it can happen for many reasons, the most common cause of the unhappy triad is a direct impact to the knee when the foot is planted and weight is on the knee. This type of impact is most common in contact sports when another person, like in football or rugby, actually physically hits the knee. However, the unhappy triad can also occur during skiing and snowboarding when the foot is planted and the knee twists or turns forcefully due to a fall at a high speed.