Anterior Cruciate Ligament (ACL)
Reconstruction

ACL reconstruction is an operation to replace your ruptured anterior cruciate ligament (ACL). A new ligament (graft) is then passed through your knee in same orientation as your native ACL to reproduce its function and restore stability to your knee. A new ligament (graft) is used to reconstruct the ACL because repairing the torn ACL has not shown to be as effective.

The new ligament (graft) is typically taken from a donor site from another part of your knee, called an autograft. The two main graft options are using the patella tendon and hamstring tendons. Both options have been shown to be successful in restoring knee stability and getting patients back to sports. Each have their advantages and disadvantages.

The patella tendon graft has been shown to have a lower re-tear rate and may provide more stability. Because of this, it is often the graft of choice for younger athletes who participate in pivoting and contact sports. However, patients typically experience more pain immediately after surgery. There is also a higher risk of long-term pain in the front of the knee around the kneecap, which can lead to difficulty kneeling. This can be problematic for patients that work as labourers or enjoy activities such as yoga.

Patients who have a hamstring graft typically have less pain immediately after surgery. There is also less chance of pain at the front of the knee or difficulty kneeling. However, it is associated with higher risks of re-tear compared to patellar tendon grafts.

Overall, there is not a huge difference between the two graft choices (patellar tendon and hamstring). Both lead to excellent results. The decision should be made on an individual basis and after discussion with your surgeon.

Using a donor tendon (allograft) is generally not recommended as there is a significantly higher risk of re-tear compared to using an autograft. Allograft is occasionally used for revision surgery or older patients.

An ACL reconstruction is indicated for most athletes who wish to return to pivoting and/or contact sports. Some patients who experience instability (knee wobbling or giving way) with day-to-day activities may also benefit from an ACL reconstruction. In patients who do not experience instability and want to return to non-pivoting activities (such as running, cycling, and swimming), ACL reconstruction may not be necessary.

ACL reconstruction can be performed once the initial swelling in the knee has resolved and you have regained full range of motion. Physiotherapy before surgery, or “prehab” to strengthen the quadriceps muscles have been shown to improve outcomes after surgery. Generally, patients can have surgery approximately 3-6 weeks after injury.

Delaying or avoiding surgery may increase the risk of further injury to the meniscus and cartilage in the knee joint. There is no conclusive evidence that having an ACL reconstruction prevents or delays the development of arthritis in the future.

Patients should have full range of motion, no swelling, and regained full muscle strength compared to the uninjured leg. This typically takes a minimum of 9 months after surgery. At this point, most patients can return to pivoting and contact sports.

In general, you can drive once you regain full power and function in your leg to safely perform an emergency brake. In addition, you must have finished taking any opioid medication. This typically takes 6 weeks after an ACL reconstruction.

The risk of a (deep) joint infection is extremely rare following arthroscopic knee surgery. You will receive a dose of IV antibiotics before and after surgery to decrease the risk of infection. Prolonged antibiotics after surgery have not been shown to provide additional benefit and are usually not required.

Symptoms of a knee joint infection include increasing pain, swelling, redness, wound drainage, decreased range of motion, and inability to weight bear.

Patients can also experience systemic symptoms such as a fever. Please contact your surgeon and/or go to the emergency department if you believe you are developing an infection.

Deep knee joint infections may require IV antibiotics and repeat surgery to “clean out” the knee.

Superficial skin infections are more common and can be usually treated with a course of oral antibiotics.

A re-tear of the ACL graft can occur after surgery. It is safest to return to sports a minimum of 9 months after surgery to allow sufficient time to regain the muscle strength in your leg.

Anterior knee pain is more common after an ACL reconstruction with a patellar tendon graft. However, it can also occur after an ACL reconstruction with a hamstring graft. This may lead to this may lead to difficulty with activities that involve kneeling.

Knee stiffness can be a problem after an ACL reconstruction. It is normal for your knee to be stiff and painful immediately after surgery. However, it is very important to work on your knee range of motion after surgery to prevent permanent stiffness. If you develop permanent stiffness, you may require repeat surgery to manipulate the knee (manipulation under anaesthesia) and arthroscopically release scar tissue (lysis of adhesions).

Patients who have an ACL reconstruction with a patella tendon graft have a small risk of a patella fracture after surgery.

A deep vein thrombosis (DVT) is a blood clot that can develop in the leg veins after surgery. DVTs that occur above the knee can be dangerous as they can dislodge and form a blood clot in the lungs called a pulmonary embolism (PE). This is a rare but serious condition which can be life threatening.

A DVT is a rare complication after an ACL reconstruction. Routine use of medication to reduce the risk of a blood clot is generally not required after surgery. If you have had a blood clot in the past it is important to inform your surgeon prior to surgery.

Damage to major nerves, such as the common peroneal nerve, is extremely rare following surgery. It is normal to have a small patch of numbness around the incisions after surgery, especially the graft harvest site (vertical incision). This typically improves over time.

Major blood vessel damage is also extremely rare but can necessitate emergency blood transfusion and vascular repair in some cases.