Anterior cruciate ligament injury

An anterior cruciate ligament (ACL) injury causes considerable knee pain and restricts the movement and stability of your knee joint.

By Wallace Health I Medically reviewed by Adrian Roberts.
Page last reviewed: October 2018 I Next review due: October 2021

What is anterior cruciate ligament injury?

The anterior cruciate ligament (ACL) connects your thigh bone to your shin bone at your knee joint. Together with the posterior cruciate ligaments, these powerful bands of tissue stabilise your knee and control the back and forth motion of your knee.

There are three types of ACL injury:

  • ACL sprain – the ligament has been stretched and has a few damaged fibres
  • Partial ACL tear – fibres in the ligament have been torn
  • Complete ACL tear – the ligament has been ripped apart (ruptured)

Other types of knee ligament injuries include:

  • Medial collateral ligament (MCL) injury – damage to the ligaments which control the sideways motion of the knee
  • Lateral collateral ligament (LCL) injury – damage to the inner side of your knee
  • Posterior cruciate ligament (PCL) injury – damage to the ligament at the back of the knee, which, in about half of all cases, occurs along with damage to other parts of the knee

ACL injury is a very common knee injury. If you play certain sports, such as football and basketball, you’re at a higher risk of knee ligament damage. Women are more prone to ACL injury.

ACL injury can be the result of:

  • Changing direction suddenly
  • Stopping abruptly
  • Landing awkwardly after jumping or falling
  • Direct contact, such as a football tackle

ACL injury can result in your knee losing its stability and full range of movement, making it difficult to perform everyday tasks or play certain sports.

Non-surgical treatment may provide your knee with the stability and mobility you require. Alternatively, your consultant may recommend reconstruction surgery to rebuild a torn ACL.

How to tell if you have anterior cruciate ligament injury

The first signs of a torn ligament in your knee include:

  • An audible popping noise
  • Sudden, severe knee pain

Other symptoms include:

  • Swelling – usually in the first few hours
  • Restricted movement of your knee
  • Tenderness and/or bruising
  • Pain when weight bearing on your knee
  • Your knee collapsing unexpectedly

Talk to your doctor if you’re concerned about symptoms

You can book an appointment with a Spire private GP today.

Diagnosis and tests for anterior cruciate ligament injury

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 and how it feels. Following an examination, your GP may refer you for tests, perhaps an ultrasound scan or MRI scan. This should reveal any damage to your ligaments and, if required, your GP will refer you to an orthopaedic consultant.

Common treatments for anterior cruciate ligament injury

You can help reduce the knee pain and swelling of an ACL sprain by:

  • Resting your knee
  • Placing ice on your knee for 20 minutes at a time every couple hours
  • Wrapping your knee with a bandage or wrap
  • Lying down with your knee elevated
  • Taking over-the-counter painkillers (such as paracetamol) to relieve the pain

If you have a partial or complete ACL tear, your doctor will advise you about non-surgical and surgical treatments.

Non-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:

Surgical treatments

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.

Highly-specialist ACL surgery uses knee arthroscopy (keyhole surgery) to rebuild your ACL, usually using part of a tendon. Following ACL reconstruction and a course of physiotherapy, you should be able to return to your chosen sport within 12 months.