What is ACL reconstruction?
The anterior cruciate ligament (ACL) is one of the four main ligaments of the knee. The ACL runs diagonally through the middle of the knee joint and prevents the tibia (shin bone) from sliding out in front of the femur (thighbone). This provides rotational stability to the knee.
Although the ligaments of knee are strong, they are frequently injured. Injuries tend to occur by:
- stopping suddenly
- landing incorrectly
- changing direction rapidly
- direct contact
ACL injuries are very common in people who play ‘pivoting’ sports such as football, netball, basketball and tennis. Women are 2–10 times more likely to injure their ACL than men. ACL injury is also more common in younger people, with 50% of ACL injuries occurring in 15-25 yearolds.
During the injury, the ligament is stretched (or sprained) and tears occur in the fibres. Sprains are graded on severity:
- A grade 1 sprain is when the ligament is mildly damaged — it has been slightly stretched, but is still able to help keep the knee joint stable
- A grade 2 sprain is when the ligament is stretched to the point where it becomes loose — this is often referred to as a partial tear of the ligament
- A grade 3 sprain occurs when there is a complete tear of the ligament — the ligament has been split into two pieces, and the knee joint is unstable
Unfortunately, when the ACL is fully torn there is usually very little healing potential, which can lead to long-term instability.
Do I need ACL reconstruction?
Signs that you may have torn your ACL include:
- a popping sound or a feeling of the knee giving way at the time of the injury
- swelling, with the severity varying with the degree of injury
- pain, with the severity varying with the degree of injury
- reduced range of motion
- tenderness when the knee is touched
- a feeling like your knee is unstable when you stand or walk on it
After discussion with your doctors, the decision to have an ACL reconstruction is yours and yours alone to make. Your doctors will always give you the options and offer the surgeryonly if appropriate.
How does ACL reconstruction work?
The aim of ACL reconstructive surgery is to give back stability to the knee. Unfortunately, a torn ACL does not heal by itself and in most cases cannot be directly repaired. Most ACL tears cannot be stitched back together, therefore the ligament must be reconstructed. This involves a tissue graft that a new ligament can grow on. There are several graft sources for an ACL reconstruction including the patellar (tendon and bone), the hamstring and Achilles tendon.
Physiotherapy is an import part of the treatment for an ACL injury. Not only is it beneficial after surgery, it is also very important to restore strength and motion to the knee before surgery (sometimes called pre-habilitation).