Your knee joint is where three bones meet; your:
These bones are connected by powerful bands of tissue called ligaments. There are four main ligaments in your knee that hold the bones together and stabilise your knee:
Damage can occur to any of these ligaments.
The ACL prevents your shinbone sliding in front of your thighbone and ACL injury is a very common knee injury. There are three types of ACL injury:
Partial ACL tears are rare. ACL injuries are usually minor sprains or complete tears. Half of all ACL injuries occur alongside other knee injuries eg damage to articular cartilage or other ligaments, or a meniscus tear.
You’re at a higher risk of ACL injury if you:
ACL injury can be the result of:
ACL injury can cause your knee to lose its stability and full range of movement, making it difficult to perform everyday tasks or play certain sports.
The first signs of a torn ligament in your knee include:
Other symptoms include:
Knee pain and swelling may go away on their own but if you return to playing sports, your knee may still be unstable and you may cause further damage to it eg injure your knee cartilage (meniscus).
You should see your GP if you suspect a knee ligament injury to avoid further damage.
Your GP will ask how you damaged your knee, how it feels and about your medical history. They will examine your injured knee and compare it to your uninjured knee. They may then refer you for tests, such as:
These tests should reveal any damage to your ligaments and, if necessary, your GP will refer you to an orthopaedic consultant.
Your treatment will depend on your individual needs. Non-surgical treatment may provide your knee with the stability and mobility you need — this is often recommended for less active and/or older individuals. Alternatively, your consultant may recommend reconstruction surgery to rebuild a torn ACL, particularly if you are a young athlete wanting to return to sports.
You can help reduce the knee pain and swelling of an ACL sprain by:
If you have a partial or complete ACL tear, your doctor will advise you about non-surgical and surgical treatments.
If you have a torn ligament in your knee and don’t participate in physically demanding sports, your doctor may suggest non-surgical treatments. These include:
If you have an ACL tear and participate in physically demanding sports, have an active lifestyle and are in good health, your consultant may recommend ACL reconstruction.
Most ACL tears can’t be stitched back together. Reconstruction surgery therefore involves replacing your torn ligament with a tissue graft. The graft acts as a scaffold onto which new ligament tissue will grow. Graft tissue is usually taken from a tendon, such as your:
Graft tissue can also come from a donor (allograft).
Your orthopaedic consultant will discuss the advantages and disadvantages of each type of graft to determine which is most appropriate for you. It takes time for new ligament tissue to grow, which means it may be six months or longer after surgery before you can return to sports.
Knee arthroscopy (keyhole surgery) is a special type of ACL reconstruction surgery that is less invasive. This usually results in less pain after surgery, less time spent in hospital and a faster recovery.
After ACL reconstruction and a course of physiotherapy, you should be able to return to your chosen sport within 12 months. However, ACL injury puts you at greater risk of developing osteoarthritis in your knee, even if you have reconstruction surgery. There are many risk factors for developing osteoarthritis, including:
Rehabilitation from anterior cruciate ligament injury
Rehabilitation is important to return to your normal activities, whether you have surgery or not. Physiotherapy will help restore your knee function and range of motion.
Initially, physiotherapy will focus on the range of motion of your knee and surrounding muscles. Next, it will focus on muscle strengthening to protect your knee ligaments; strengthening gradually increases the stress on the ligaments. Finally, physiotherapy will aim to restore function related to the sport you want to return to playing.
Appropriate exercise and training can help prevent ACL injury. There are several different specialists who can assess your physical condition and advise you on how to reduce your risk of injury; this includes athletic trainers, physiotherapists, sports medicine doctors and other sports medicine specialists.
Programmes to reduce your risk of ACL injury include:
Can an ACL tear heal without surgery?
ACL tears can heal over time without surgery by following a physiotherapy programme and using crutches and knee braces. However, if you take part in physically demanding sports and want to return to them, your doctor may recommend surgery.
Can you walk with a torn ACL?
This depends on the severity of your ACL tear. You may be able to walk on it but may experience discomfort or pain.
Is ACL surgery a major surgery?
Yes, ACL surgery is a major surgery. It involves reconstructing your torn ligament using a tissue graft. Complete restoration of knee function for physically demanding sports can take six months or longer after surgery.
Where is ACL pain located?
Pain caused by an ACL injury is located in the centre of your knee.