Anterior Cruciate Ligament

The Anterior Cruciate Ligament (ACL) is one of the 4 major ligaments of the knee. It is important in providing stability of the knee joint.

An unstable knee

The ACL is the most commonly injured knee ligament and is commonly damaged by athletes. The ACL is often torn during sudden movements of the knee. Commonly patients report hearing or feeling a "pop", but pain at the time of ACL rupture can vary from moderate to severe, however, strong painkillers are normally needed. In the hours following ACL rupture, however, most patients notice progressive swelling (usually due to bleeding of the vessels along the torn ACL). This swelling generally is quite painful, but can be minimized by icing the knee. ACL tears typically occur in sports where cutting, twisting, and turning are common, such as skiing, basketball, gymnastics, American football, Australian football, and soccer.

Although ACL tears don’t heal in the correct mechanical axis for knee stability, they may scar and provide limited stability for non-active people. As the ligament does not heal like most other ligaments in the body, a reconstruction is the most effective surgical procedure rather than a direct repair - I.e. using another tendon/ligament as a substitution.

The Surgery

Before surgery is undertaken, several goals must be achieved. The knee must have full extension, and near full knee flexion. The quadriceps muscle must be normal. A physiotherapist is usually used to help "Prehab" the knee before surgery.


The operation is performed arthroscopically. The 2 main "donor" sites are the Hamstrings (2 of the 3 smaller tendons in the inside portion of the knee) or the Patella Tendon. The majority of procedures are done using the hamstrings.

A general anaesthetic or spinal anaesthetic is generally used. The "donor" tissue is harvested using a 3 cm incision. This is then prepared is the standard fashion.

A knee arthroscopy is performed. Other injuries will be addressed at this stage. Procedures such as meniscal repairs will be performed.

The old ACL is removed, and appropriate tunnels are made in the tibia and femur. The new tendon is inserted in these tunnels, and fixed with various devices to hold them in place.

Post-Operative Period

Patients will be seen after the surgery and provided with photos from the surgery with explanations.

Patients will either go home on the day of surgery, or the following day, after a review by the physiotherapist. You will be provided with the ACL protocol.

Wounds should be left intact. Absorbable stitches will be used. The large "Crepe" dressing can be debulked at day 2. The small rectangular dressings must be left intact until review.