Overview

The anterior cruciate ligament (ACL) is one of the bands of tissue within the knee joint that connects the femur to the tibia. An ACL tear can be painful and cause the knee to become unstable.

Causes

The ACL can tear during abrupt movements such as sudden stops, pivots, or directional changes that can occur during athletic activity. These same forces can be generated in crashes or slip/trip and fall events, also leading to ACL tears.

Symptoms

A common symptom of an ACL tear is a popping sound or sensation in the knee at the moment of injury. The knee may be very painful, and it may swell. It may feel unstable. The person may be unable to continue physical activity.

Treatment

In some cases, an ACL tear can be treated conservatively in patients who have a low activity level. Nonsurgical options may include crutches, a knee brace, and strengthening and stability exercises. For active patients, surgery and rehabilitation are commonly required.