Understand the three injuries that make up an Unhappy Triad

The unhappy triad, or terrible triad, is the tearing of the ACL, MCL, and meniscus simultaneously

Defining the Unhappy Triad

The unhappy triad is the name given to a knee injury in which the person injures their ACL, MCL, and meniscus at the same time, thus injuring all three important ligaments and tendons in the knee. Normally for an unhappy triad, also known as a terrible triad or O’Donaghue’s triad, the person must have completely or partially torn each ligament. Given the severity of injuring all three of these areas, the unhappy triad usually requires surgery and rather extensive and lengthy recovery and rehabilitation.

The major and usually most severe injury in the unhappy triad is the torn ACL, or anterior crucial ligament. This ligament is located in the back of your knee and connects your femur and tibia. Unfortunately, the ACL can not heal on its own and almost always requires reconstructive surgery. This surgery, the most serious of the unhappy triad procedures, can have a recovery time of between 4-7 months. After the ACL tear in the unhappy triad, the next most serious injury is the torn meniscus. A meniscus tear usually can not heal on its own either and also requires surgery to heal. The procedures can be done simultaneously. Finally, the MCL tear in the unhappy triad is the least worrisome and normally heals on it’s own. The knee will be set in place after surgery and the MCL will have time to heal during this period of stabilization.

The most common way that someone injures their knee and ends up with the threesome of injuries known as the unhappy triad is during contact sports and more extreme sports. When a person’s weight is planted in one place and their knee is forced or pushed in another direction, this can cause the ligaments and cartilage to tear. This is especially true when the knee is hit, like in football, or when the knee is twisted very rapidly, like in a skiing injury.

Unhappy Triad Symptoms

Learn about the most common symptoms of an unhappy triad injury and what many people experience who have injured their knee in all three places.

  • Swelling in and around the knee
  • Bruising in and around the knee
  • Popping sound at the time of injury
  • Difficulty or inability to bend or straighten knee
  • Pain in knee and surrounding area
  • Knee unstable and wobbly

Unhappy Triad Causes

The unhappy triad can be caused by a variety of incidents, but the list below shows some of the most common ways people get the unhappy triad.

  • Contact sports like football and rugby
  • Forceful twisting of the knee
  • Lateral impact to the knee joint
  • Skiing or snowboarding accidents and falls
  • Knee is pushed forcefully when foot is planted
  • Major forced torsion of the knee joint