What is the anterior cruciate ligament (ACL)?
This is one of the main ligaments in the knee. The ligaments are found around the knee and are very tough structures that stabilise the joint. The anterior cruciate ligament is found inside the joint itself; if the ligament is torn or ruptured then the knee can collapse or give way when making twisting or turning movements. This may interfere with sports or even normal daily activity.
How does ACL rupture happen?
The usual cause is a twisting injury to the knee, such as may happen in football or skiing. The other ligaments or cartilage of the knee may also be damaged at the same time. The knee often becomes swollen and painful, but this usually settles in time.
Is surgery the only option for ACL rupture?
If your specialist feels that you have an ACL rupture, then physiotherapy and exercises may well be the first treatment method attempted. The exercises are aimed at strengthening the muscles around the knee joint, which can lead to a stable joint again.
If the joint continues to be unstable during sports, then a knee brace can be worn to give more stability during the sporting activity. The brace is usually too awkward to be worn all the time, though.
If the knee still continues to be unstable during everyday activity, then surgery may be needed. Surgery is also often required for high-level athletes.
How is ACL reconstruction performed?
The operation is performed either by 'keyhole' surgery, or by making cuts at the front and side of the knee. A piece of tendon is then taken from either the kneecap tendon or the hamstrings. This piece of tendon is used to replace the ACL, being held in place by special screws or anchors. The skin is then stitched closed.
What happens after the operation?
Your physiotherapist will help you to mobilise and strengthen the knee, often requiring a knee brace for a few weeks.
You will usually be able to go home after 1 to 2 days. Your specialist and physiotherapist will be able to guide you as to how much exercise you can do with the reconstructed knee. You should check with your specialist and insurance company before starting to drive again. Whilst your new knee will often give a good range of movement, it may never feel as good as a normal knee.
You will have the best chance of a successful outcome if you follow the advice of the physiotherapist and have a healthy body weight.
What are the risks of ACL reconstruction surgery?
Infection - this may need antibiotics or further surgery to wash out the knee.
Damage to nerves - this is quite uncommon, but can lead to numbness or weakness in the leg or foot.
Blood clots in the legs - clots in the calf (deep vein thrombosis / DVT) occurs in about 1 in 500 ACL reconstructions. These can usually be treated with medication, but a DVT can (rarely) move to the lungs. This can cause breathing difficulty, or even death.
Stiffness - it is quite common to have a degree of stiffness in the knee, which can often be improved with physiotherapy. Occasionally, a short procedure may be needed to stretch the knee joint under anaesthesia to improve movement.
Breaking of the kneecap - if a patella (kneecap) tendon has been used for reconstruction, then the bone can occasionally break. This may need further surgery.
Discomfort - the front of the knee can be uncomfortable, but this does not usually cause too much bother unless if kneeling.
Giving way of the knee - this can occasionally recur, and may be the result of the graft stretching or a further knee injury. Another procedure may be needed to strengthen the ACL again.
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Any procedure involving skin incision can also result in unfavourable scarring, wound infection, or bleeding. This list of risks is not exhaustive, and you should discuss possible complications with your specialist. Whilst these risks will seem very worrysome, and indeed can be serious, it should also be borne in mind that many people have no postoperative problems whatsoever.
The information provided is as a guide only and you should discuss matters fully with your specialist before deciding if this is the right procedure for you. Please also read our disclaimer