What causes ACL tears?

The ACL can tear when there is sudden, abrupt change in force to the knee. This can happen when we bend our knee sideways, stop or change direction suddenly, or twist our knees. This can happen during accidents while skiing, bicycling or riding in a car. It also can happen during sports that require a lot of jumping, pivoting and quick stops and starts, such as basketball, volleyball and soccer. We can also tear the ACL when we stumble or fall, or when we run into others while playing sports. Typically, the tear will make a popping sound at the time of injury, accompanied by swelling, and the injured person may be unable to walk.

Return to ACL Care page.