Anterior Cruciate Ligament (ACL) Reconstruction

The anterior cruciate ligament is one of a pair of ligaments that lie within the knee joint, and connect the tibia (lower leg bone) to the femur (thigh bone).

The ACL lies in front of the PCL, seen here in a flexed knee. The lateral collateral ligament (LCL) and medial collateral ligament (MCL) contribute to the side-to-side stability of the knee.

A tear of the anterior cruciate ligament is a common injury, frequently sustained during sports activities such as football, rugby, netball and skiing. Patients invariably remember the injury as being quite significant, with rapid swelling, and usually an inability to finish the game or ski run. Once torn, the ligament does not properly heal itself.

Many people have symptoms of ongoing instability (the knee feels as if it may “give way”) following this type of injury. It may prevent them from returning to sports activities. Others find that their knee can cope without the ACL and have no symptoms of instability.

Some people choose to adapt their lifestyle to avoid activities that may cause instability. Physiotherapy, directed at hamstrings and quadriceps strengthening, can assist in restoring the sensation of stability.

The surgical treatment is to replace the ligament with a graft taken from elsewhere in the body, such as the hamstrings or patellar tendon.

The surgery is performed arthroscopically (keyhole surgery), and patients typically return home either the same day, or within 24 hours of the operation.

One of the downsides to the surgery is the lengthy rehabilitation period following the operation. A six to nine month course of physiotherapy and training is essential to help the knee recover sufficient strength to return to sports activities. If this rehabilitation is not performed properly, there is a risk of re-injury to the ACL graft.

Most people can return to sedentary work by 3-4 weeks after the operation. 90% of people have a good to excellent result following the rehabilitation period, but occasionally some will experience ongoing instability.

For more information on rehabilitation after an ACL injury, please see the ACL rehabilitation advice pages.