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Anterior cruciate ligament reconstruction

Have you injured your knee or have a long-term knee problem?

The Bupa knee clinic can help you find the information and support you need.

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ACL reconstruction can improve the stability and the function of your knee following an injury. It involves replacing the ACL in your knee, usually using a tendon from another part of your body. You will meet the surgeon carrying out your procedure to discuss your care. It may differ from what’s described here as it will be designed to meet your individual needs.

About anterior cruciate ligament reconstruction

The ACL is a strong ligament that runs diagonally through the middle of your knee. It helps to keep your knee stable, especially when you turn, or when your knee joint moves from side to side.

The ACL is one of the most commonly injured ligaments. It's usually torn when you slow down very quickly while turning or sidestepping at the same time. You’re more likely to injure your ACL if you play sport, particularly basketball, netball, rugby or football, or if you ski.

Illustration showing ACL reconstruction

ACL reconstruction involves replacing your torn ligament with a graft. The graft is usually taken from a tendon in another part of your knee, for example, your hamstring or patella tendon. But sometimes it can be a graft from a donor. This is called an allograft. Your surgeon will discuss the different graft options with you.

ACL reconstruction is carried out to try to make your knee stable. This means that you may be able to return to playing sport. However, it will depend on whether there are other problems with your knee, such as torn cartilages, other ligament injuries or arthritis. 

What are the alternatives to anterior cruciate ligament reconstruction?

Some people with an ACL tear may not need an operation to repair it. You may be offered physiotherapy, exercises and a hinged knee brace to give your knee support. Your doctor may suggest this type of treatment if: 

  • your knee is stable
  • you have partially torn your ligament, rather than fully torn it
  • you don’t want to play sports that place a lot of strain on your knees

Your doctor is likely to suggest a reconstruction if your knee is unstable (gives way) and you:

  • want to return to playing sport
  • have an active job
  • have other damage to your knee

Also, if you’re at risk of osteoarthritis later in life, then your surgeon may also suggest an ACL reconstruction.

Preparing for an anterior cruciate ligament reconstruction

You will usually have ACL reconstruction three to eight weeks after your injury. This allows any swelling to go down. Your surgeon may ask you to have physiotherapy during the weeks after your injury. This is to make sure you can move your knee as fully as possible before your operation.

Your surgeon will explain how to prepare for your operation. For example, if you smoke, you will be asked to stop. This is because smoking increases your risk of getting a chest and wound infection, which can slow your recovery.

ACL reconstruction can be done using either local or general anaesthesia. A local anaesthetic completely blocks pain from your knee area and you will stay awake during the operation. If you have a general anaesthetic, it means you will be asleep during your operation.

If you're having a general anaesthetic, it’s important to follow your anaesthetist’s advice. You will usually be asked to not eat or drink for about six hours beforehand.

Your surgeon will have a chat with you about your procedure and any pain you might have. Take this time to ask any questions you’d like answered so you understand what will happen. It can be helpful to prepare some questions beforehand. You may also be asked to give your consent for the procedure to go ahead by signing a consent form.

What happens during an anterior cruciate ligament reconstruction

Your surgeon will examine your knee to check how badly your ligament is torn and if any other tendons or ligaments have been damaged.

Your surgeon will make a number of small cuts in the skin over your knee that is being treated. These cuts are called portals. He or she will insert an arthroscope and other surgical instruments into your knee through these cuts. An arthroscope has a thin, flexible tube with a light and camera on the end of it. This allows your surgeon to see inside your knee.

Your surgeon will remove the piece of tendon that will be used as the graft. He or she will usually take the graft from your patella tendon, which connects your kneecap and shin bone. Or from one of your hamstring tendons at the back of your knee.

Your surgeon will drill a tunnel through your upper shin bone and lower thigh bone. He or she will put the graft into the tunnel, attach it to your bones and fix it in place, usually with screws. These are normally left inside your knee permanently. Your surgeon will close the cuts with stitches or adhesive strips.

Your operation will usually last between one and a half and two hours.

What to expect afterwards

You will need to rest until the effects of the anaesthetic have passed. And you may need pain relief to help with any discomfort as the anaesthetic wears off.

After a local anaesthetic it may take several hours before the feeling comes back into your treated knee. Take special care not to bump or knock the area. It’s best to keep your leg elevated as much as possible.

General anaesthesia temporarily affects your co-ordination and reasoning skills. You must not drive, drink alcohol, operate machinery or sign legal documents for 24 hours afterwards. If you're in any doubt about driving, contact your motor insurer for their recommendations, and always follow your surgeon's advice.

Dressings will cover the small wounds. You may also have a knee brace to give some support to your joint as it heals.

You will be encouraged to get up, put weight through your knee and move it as soon as you’re able to. But you should arrange for someone to drive you home. And you should try to have a friend or relative stay with you for the first 24 hours after your operation.

Your nurse will advise you 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 an anterior cruciate ligament reconstruction

If you need pain relief, you can take over-the-counter painkillers such as paracetamol or ibuprofen. Always read the patient information that comes with your medicine and if you have any questions, speak to your pharmacist for advice.

You can also apply ice packs or frozen peas wrapped in a towel, to your knee to help reduce any pain and swelling. Don't apply ice directly to your skin though as it can damage it.

It usually takes about six months to make a full recovery from ACL reconstruction. However this does vary between individuals, so it's important to follow your surgeon's advice. If you have a desk job, you may be able to go back to work three to four weeks after your operation. However, it may take up to six months if you have an active job.

If you want to play sport after your operation, follow your surgeon’s advice about when it’s safe to do so. You may not be able to play some sports that involve lots of twisting and turning, for example basketball.

What are the risks?

As with every procedure, there are some risks associated with ACL reconstruction. We haven’t included the chance of these happening as they are specific to you and differ for every person. Ask your surgeon to explain how these risks apply to you.


Side-effects are the unwanted but mostly temporary effects you may get after having the procedure.

After ACL reconstruction you may get some side-effects. These can include:

  • pain
  • swelling and bruising
  • stiffness


Complications are when problems occur during or after your operation. The possible complications of any operation include excessive bleeding, developing a blood clot, usually in a vein in the leg (deep vein thrombosis). Or having an unexpected reaction to the anaesthetic.

The main complications of ACL reconstruction are listed below.

  • Tearing of the graft used to repair your ACL. This is known as graft failure. 
  • Numbness along the outside of your upper leg, near where the surgical cuts were made. This can be temporary or permanent. 
  • Your knee joint may remain unstable. This can happen if the graft tears or stretches.
  •  Stiffness in your knee, or less movement than you had before your injury. This is called arthrofibrosis.
  •  The tendons your graft was taken from may weaken and tear.
  •  Long-term knee pain, or pain when you kneel down.

Reviewed by Dylan Merkett, Bupa Health Information Team, August 2014.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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Bupa Knee Clinic

Injured your knee or have a long term knee problem? The Bupa knee clinic can help you find the information and support you need.

Visit the clinic