ACL reconstruction

The anterior cruciate is a ligament which is present inside the knee linking the thigh bone to the shin bone. This ligament gives important feedback to the brain for activating the appropriate muscles, particularly when you are running, twisting and turning at speed.

Damage to this ligament leads to instability of the knee with recurrent giving way. The common injuries that cause damage to the anterior cruciate ligament (ACL) include sports injuries while playing football or rugby. A twisting injury to the knee while skiing is also a common way by which people injure their ACL. At the time of initial injury, a popping sensation is felt in the knee followed by swelling of the knee which gradually settles down over a period of a few weeks but then leads to recurrent giving way, either during everyday activities or while engaging in sports.

Injury to the anterior cruciate ligament is diagnosed by a clinical examination and MRI scan of the knee. In the initial phases rest and physiotherapy is advised to reduce the swelling and regain the full movement in the knee.  If your knee feels stable following a course of physiotherapy, you may not need knee surgery, provided you are happy to accept certain lifestyle changes. If your knee feels persistently unstable during everyday activities or you are keen to resume sporting activity you will benefit from reconstruction of the ACL.

What happens during ACL reconstruction?

The surgery is usually carried out as a day case procedure under general anaesthetic and local nerve block to ensure good pain control after surgery.

Two of the hamstring tendons are used to reconstruct the anterior cruciate ligament.  The tendons are removed via a small incision just below the knee. The tendons are doubled over to form a four-strand ligament to replace your ACL. The strength in your hamstrings returns almost back to normal within a year following the surgery. Rest of the procedure is done by the arthroscopic (keyhole) surgical technique. Any associated injuries like a torn cartilage are dealt with at the time of the arthroscopy. The tendons are pulled through the knee after drilling tunnels through the lower end of thigh bone and upper end of leg bone. The tendons are fixed securely to the bone using screws. This allows the tendons to heal quickly to the bone. Surgical wounds are closed with metal clips.

What happens after ACL reconstruction?

Once you have recovered from the anaesthetic you can walk putting full weight through the leg. Physiotherapists help with your mobilisation. You are able to go home the same day. Your knee is supported with a brace for the first two days. The brace is removed after two days following which you can start working on the knee movements. Physiotherapy is organised for you as an outpatient. The physiotherapist will help you to regain the full movement in your knee and strengthen the muscles around the knee. You will be able to increase your activities under the supervision of the physiotherapists. You can start jogging and running two to three months after the surgery. Six months following the ACL reconstruction you can start retraining for the sport that you want to resume. You can get back to all sporting activities nine months after the surgery.

What can I expect from my knee following ACL reconstruction?

The surgery aims to restore the stability to your knee and allows you to get back to pre-injury activities.

What are the risks of having an ACL reconstruction?

  • Infection (1%): the wound site and the knee may become red, hot and painful.  Infection is usually treated with arthroscopic washout of the knee and antibiotics.
  • Bleeding: minimised by use of tourniquet during the surgery.
  • Deep vein thrombosis and pulmonary embolus: deep vein thrombosis (DVT) is a blood clot in the veins of the leg.  The blood clot can go into the general circulation and go to the lungs, which is termed as a pulmonary embolus.  To reduce the risk of DVT you will be given blood thinners as well as stockings on your legs.  One of the best ways to prevent a DVT is to get the calf muscles working by ankle exercises and keeping yourself well hydrated.
  • Swelling: swelling in and around your knee can take few weeks to settle down.
  • Stiffness: The knee can stiffen due to scar tissue. This can be prevented by early exercises following the surgery.
  • Persistent pain: can occur due to scar tissue and overactivity of nerves around the knee. This may need input from pain clinic.
  • Rare complications include nerve and blood vessel damage.
  • Rupture of the new ligament: the tendons used to replace your ACL may tear. This can occur if there is a further significant injury to the knee. If there is recurrence of knee instability, this is treated with performing the ACL reconstruction again (revision ACL reconstruction).