Anterior Cruciate Ligament Rupture

The Anterior Cruciate Ligament (ACL) is one of a pair of cruciate ligaments (the other being the posterior cruciate ligament) in the human knee. They are also called cruciform ligaments as they are arranged in a crossed formation. The anterior cruciate ligament is one of the four main ligaments of the knee, and the ACL provides most of the restraining force to anterior tibial displacement during knee flexion.

Cause

Most commonly occurs during sports that involve sudden stops, jumping or changes in direction. There are cases where the ACL is torn gradually through repetitive trauma, but most of the time ACL rupture happens from one serious injury.

Symptoms

Severe pain and inability to continue activity

A loud "pop" or a "popping" sensation in the knee

Swelling that begins within a few hours of injury

A feeling of instability or "giving way" with weight bearing

Loss of range of motion, but you may not feel it when you are walking, sitting, or standing up

Tests and Diagnosis

Often simple X-Rays, physical exams, and other imagings like MRIs can suffice to make a diagnosis.

Treatment

Conservative treatment

You may also wear a brace to stabilize your knee and use crutches for a while to avoid putting weight on your knee. After a period of time for stabilization, you may start rehabilitative physical therapy. However, even after recovery, your ligament may not be as strong as it originally was, so this only applies for partial ACL rupture.

Surgical treatment

Suture: Use stiches to reconnect the torn ACL. This option is recommended if the torn area is closely located to femur when the tibial attachment is accompanied by avulsion fracture.

ACL Reconstruction: Remove the damaged ligament and replace it with a segment of tendon — tissue similar to a ligament that connects muscle to bone. This replacement tissue is called a graft. Your surgeon will use a piece of tendon from another part of your knee or a tendon from a donor. The graft will serve as scaffolding on which new ligament tissue can grow.