ACL Reconstruction

Anterior Cruciate Ligament

ACL reconstruction is one of the most common surgical procedures performed on the injured knee. At the time of surgery, the ruptured ACL is removed and the autologous hamstring graft is placed anatomically and held with screws and occasionally a staple.

The anterior cruciate ligament is an intraarticular (within the joint) ligament, and as such heals poorly. For this reason, it is almost always reconstructed with a substitute ligament, rather than being repaired.


In our practice, the hamstring tendons are used almost exclusively. There remains disagreement as to whether the patella tendon or hamstring tendon repair is best. Review of the latest literature shows that there is little difference in outcome although hamstring reconstructions allow for an easier post operative rehabilitation for the patient.

The rationale for treatment is to stabilise an unstable joint, or a potentially unstable joint. Joint stabilisation has been shown to decrease meniscal and articular cartilage injury. This should, in turn, decrease the incidence of later osteoarthritic change. It will also allow return to activities that were difficult secondary to joint instability.

ACL reconstruction is usually performed under general anaesthetic (asleep) to ensure the muscles surrounding the joint are adequately relaxed to conduct the procedure. Local anaesthetic is infiltrated around the knee at the end of the operation to help limit pain.

Four incisions, approximately 5mm-20mm in length, are made around the knee to place the camera and surgical instruments into the joint, harvest the graft and pass it into the knee. ACL reconstruction usually takes between 45 minutes and 2 hours, depending on the complexity of the operation.

Most patients experience only mild discomfort when they wake up after an ACL reconstruction. The knee will have a bulky absorbent pad applied, which may become damp with the irrigation fluid used during the procedure. It is normal for the fluid to have a faint red tinge, and small amounts may continue to drain for 24-36 hours. Most patients will go home the same day.

Unless instructed otherwise, patients can bear as much weight on the leg as comfort allows immediately after the surgery. Crutches may be used for comfort where necessary, and are usually required for 2-3 days.

Most people are walking reasonably comfortably by 2 weeks and can commence running in a straight line by 6 weeks. It is important not to over-exert too early after the procedure as this can increase discomfort and swelling. Other activities can be gradually reintroduced within ones level of comfort.

Driving is allowed the next day. People with desk jobs can return to work as early as 1-2 days, while people in more heavy manual employment may require 6 weeks.

The rehabilitation program runs over a 6-12 month period prior to returning to competitive sports or unrestricted activity.

Yes. Rehabilitation following ACL reconstruction is an essential part of full recovery. Ideally this rehabilitation should be carried out under the guidance of a physiotherapist.

Post operative information will include a rehabilitation program to guide your physiotherapist through your rehabilitation as your surgeon thinks it should be done. All rehabilitation programs are flexible. Individual progress varies greatly, and this will require some modifications of the program at the discretion of the physiotherapist. Different techniques may also be used by the physiotherapist depending on available equipment, and individual needs to meet the described aims.

ACL reconstruction is a very safe procedure. The most common side effect of ACL reconstruction is temporary discomfort or slight bruising. Due to the skin incision patients may notice a numb patch on the outer aspect of their leg past the skin incision. This is of no functional significance and is unavoidable. The numb patch tends to shrink with the passage of time and does not affect the result of the reconstructed ligament.

Graft failure due to poorly understood biologic reasons occurs in approximately 1% of grafts and a further 1% of grafts rupture during the rehabilitation programme.

As with all operations if at any stage anything seems amiss it is better to call up for advice rather than wait and worry.

Any surgical or invasive procedure carries risks. The information provided here is for general educational purposes only.
For specific advice regarding an ACL reconstruction in your situation, please make an appointment with one of our specialist surgeons.