This factsheet is for people who are planning to have anterior cruciate ligament (ACL) reconstruction, or who would like information about it.
An ACL reconstruction involves replacing the anterior cruciate ligament in the knee. It’s done to improve the stability and the function of the knee, often after an injury.
Your care will be adapted to meet your individual needs and may differ from what is described here. So it’s important that you follow your surgeon’s advice.
- About ACL reconstruction
- What are the alternatives?
- Preparing for your operation
- About the operation
- What to expect afterwards
- Recovering from ACL reconstruction
- What are the risks?
About ACL reconstruction
The anterior cruciate ligament (ACL) is a strong ligament that runs through the centre of the knee. It controls the stability and the movement of the knee. It’s usually damaged by twisting or overextending the knee, often combined with slowing down very quickly, especially during sports. The common causes are football and skiing.
ACL reconstruction involves replacing the anterior cruciate ligament of the knee with a graft. The graft is usually a section of tendon taken from another part of your knee, but sometimes it’s a donor graft (allograft). At the moment, synthetic grafts are not recommended. Your surgeon will discuss the different graft options with you.
The operation is normally performed using a narrow, tube-like telescopic camera called an arthroscope. This means that the surgeon will only make several small cuts to examine the inside of the knee and to replace your torn ACL. Getting the donor graft will also need one or two additional small cuts in the skin.
What are the alternatives?
For some people, ACL reconstruction isn’t necessary. Knee instability can often be managed by appropriate physiotherapy, maintenance exercises and by stopping vigorous sports. However, if your symptoms interfere with your everyday life and sporting activities, and physiotherapy hasn’t helped, ACL reconstruction is an option.
Preparing for your operation
Your surgeon will explain how to prepare for your operation. For example, if you smoke, you will be asked to stop as smoking increases your risk of getting a chest and wound infection, which can slow your recovery.
ACL reconstruction can be done under general anaesthesia, which means that you will be asleep during the procedure, with an overnight stay. The operation can also be done under local or regional anaesthesia as a day case. This completely blocks feeling from the knee and the leg, and you will stay awake during the operation. You may be offered sedation with a regional anaesthetic to help you relax during the operation.
If you’re having a general anaesthetic, you will be asked to follow fasting instructions. Typically you must not eat or drink for about six hours before a general anaesthetic. However, some anaesthetists allow occasional sips of water until two hours beforehand.
At the hospital your nurse may check your heart rate and blood pressure, and test your urine.
Your surgeon will ask you to sign a consent form. This confirms that you understand the risks, benefits and possible alternatives to the procedure and have given your permission for it to go ahead.
About the operation
A number of small incisions (usually less than 10mm long) are made in the skin over the knee that is being treated. Your surgeon will insert the arthroscope and other surgical instruments into the knee through these cuts. Sterile fluid is put into the joint to help extend the joint and get a clearer picture of the inside of the joint. Your surgeon will then trim the torn ligament and prepare the knee for the replacement graft.
A graft will usually be taken from your patella tendon, which connects your knee cap and shin bone, or from part of your hamstring tendon. Your surgeon will then drill a tunnel up through your upper shin bone (tibia) and lower thigh bone (femur), diagonally from the inside of your knee to the outside, above your knee.
The graft will be inserted in the tunnel, attached to the bones and fixed in place, usually with screws. The incisions are closed with stitches or adhesive strips. The operation usually lasts one to two hours.
What to expect afterwards
You will need to rest until the effects of the anaesthetic have passed. General anaesthesia temporarily affects your coordination and reasoning skills, so you must not drive, drink alcohol, operate machinery or sign legal documents for 48 hours afterwards. If you’re in any doubt about driving, contact your motor insurer so that you’re aware of their recommendations, and always follow your surgeon’s advice.
After a regional anaesthetic it may take several hours before the feeling comes back into the treated knee. Take special care not to bump or knock the area.
When you feel ready, you can begin to drink and eat, starting with clear fluids. Dressings will cover the small wounds and a bandage will support your knee and help to control swelling. You will be encouraged to move your knee soon after surgery to stop the joint becoming stiff.
You will need to arrange for someone to drive you home. You should try to have a friend or relative stay with you for the first 24 hours.
Your nurse will give you some advice about caring for your healing wounds before you go home. You may be given a date for a follow-up appointment.
You will also see a physiotherapist who will give you some exercises to do while you recover. The amount of physiotherapy you need varies, so follow the advice of your physiotherapist and surgeon.
Recovering from ACL reconstruction
It can take between six and 12 months for you to recover your knee function after an ACL reconstruction. However, this depends on the individual so you should follow your surgeon’s advice on returning to your usual physical activities and sports. You must also follow your surgeon’s advice about driving and returning to work. You shouldn’t drive until you’re confident that you could perform an emergency stop without discomfort.
You can also apply ice packs (eg frozen peas wrapped in a towel) to your knee to help reduce any pain and swelling. Don’t apply ice directly to your skin as it can damage your skin.
What are the risks?
Anterior cruciate ligament reconstruction is commonly performed and generally safe. However, in order to make an informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications of this procedure.
The exact risks are specific to you and differ for every person, so we have not included statistics here. Ask your surgeon to explain how these risks apply to you.