ACL reconstruction


Ligaments are bands of fibrous tissue that connect bone to bones (tendons connect muscles to bones). The two ligaments that keep the knee joint together and keep the joint stable are the two cruciate ligaments – the Anterior Cruciate Ligament ('ACL') and the Posterior Cruciate Ligament ('PCL') – which cross over each other forming an 'x' shape (hence the word 'cruciate' which means 'like a cross'). The ACL is more prone to injury – known as an ACL rupture than the PCL.

Preoperative Instructions

  • Existing medication(s) – some medications can impact surgery, especially any anti-coagulant medication and medicine for diabetes; we will advise if any of your medication needs to be stopped (and when) well ahead of the day of surgery. Any other medication should be taken the morning of surgery with a little water (half a cup maximum).
  • You should not shave (or wax) skin near where any surgical incisions will be made.
  • No solid foods (cow's milk and drinks containing cow's milk are considered food) should be consumed within 6 hours of surgery; clear fluids (e.g. water, cordial) may be consumed until 3 hours before surgery and then nil by mouth from that point.
  • Please advise us if you have a cold or fever, a cough or any other injuries or infections (e.g.: urinary tract infection or cuts/tears to the skin) – your procedure may need to be postponed as any of these may make anaesthesia or surgery unsafe.
  • Please bring all imaging (e.g.: x-rays / CT scans / MRI scans) with you to hospital.
  • Please come to hospital at least one hour before your planned surgery, unless we advise you otherwise.

In very general terms make sure you follow a healthy and balanced diet before surgery and continue any regular physical activity up until the day of the procedure. If you smoke, you should ideally stop smoking at least four weeks before the procedure and otherwise as a minimum at least one week before.


Most ACL reconstruction procedures are completed using arthroscopic techniques and are conducted under a general anaesthetic.

Once the anesthetic has taken effect, the knee joint is checked to see if the ACL has in fact been damaged and whether there has been any other soft tissue damage in the knee. Where the ACL needs to be repaired then a replacement ligament is sourced, either an 'allograph' (a donor tendon) or another one of the patient's tendons is used (often a hamstring). The replacement tendon graft is then made to match the original ACL and is fitted to the knee joint.

This is generally performed via arthroscopy where a number of small (1cm) incisions are made around the knee to allow surgical instruments and a miniature video camera access to the joint. If there has been any damage to either cartilage and/or meniscus tissue this is repaired, and any remaining section of the original ACL are also removed. The replacement ligament is then fitted and checked for the correct tension and stability, and the joint is then also checked to make sure it has the correct range of movement. Once everything is functioning as it should, the surgical instruments and camera are removed, and the incisions are closed.

Postoperative Instructions

After arthroscopic ACL reconstruction surgery most patients are able to return home the same day. Patients are strongly advised not to drive, return to work or make any important decisions until the next day, due to the continuing effect of the anaesthetic. A crutch may be given to the patient if needed before returning home.

Any pain and/or swelling from the surgery generally reduces over 24-48 hours. Recovery however can take 4-6 months and a specific rehabilitation exercise program must be followed to achieve this - more details on this program is given to patients after surgery.

The operative site needs to be kept clean and dry for the first 2 weeks until sutures are removed. The range of motion brace (ROM) will remain locked for the first 1-2 weeks in order to maintain full extension. Thereafter, the brace will be unlocked to 90 degrees (till week 4) and thereafter weaned off.


As with any surgery, after the procedure there is always a risk of:

  • Pain.
  • Bleeding.
  • Scarring.
  • Infection (of the incision site, or in the chest).
  • Blood clot (leg or lung).
  • Stroke.
  • Heart attack.

Some specific risks of ACL reconstruction surgery include:

  • Nerve damage causing short (or longer term) numbness around the knee.
  • Damage to blood vessels.
  • Where the graft is taken from another part of the body, pain in that area.
  • Issues with the ligament graft (e.g.: scarring, loosening, stretching).
  • Issues with any components (e.g.: screws) use to fix the ligament graft in place.

Related Information

ACL rupture