The Anterior Cruciate Ligament (ACL) is a supportive ligament located within the knee joint. It stops the shin bone (tibia) sliding forward on the thigh bone (femur). ACL injuries can be the result of contact and non-contact sports. Often they are from non-contact sports that involve side stepping (cutting), jumping and landing, and deceleration (quickly stopping). AFL, soccer and netball are a good example of sports that involve these movements with high amounts of ACL injuries.
When the ACL is torn an audible ‘pop’ can often be heard and pain and swelling within the knee occur immediately after the injury. The knee can become very swollen. It will be difficult to walk or put weight through the leg and there will be feelings of instability.
The treatment for an ACL tear is generally surgical treatment with 9-12 months of progressive physiotherapy-led exercise rehabilitation. Exercises are designed to improve the knee function to the pre-injury level, ensuring quadricep strength, jumping and landing and good hip stiffness is at its foundation. Read more.
Frequently Asked Questions
How does an ACL injury present?
At the time of the injury, you may hear a ‘pop’ sound that can be felt deep within the knee joint. The pain is often sudden and sharp, increasing with movement and weight-bearing activities. There is immediate swelling that will develop rapidly within the initial 1-2 hours post-injury. Due to pain and swelling, you will experience reduced knee range of motion, particularly extension. As a result of these impairments, there will be difficulties with general function such as squatting, jumping, and walking.
How is an ACL injury diagnosed?
At your first appointment with your physiotherapist, a detailed medical history will be taken including how the injury occurred, what symptoms you have and if you have previously injured that knee. A physical examination of special tests such as the Lachman test, Anterior Drawer test and Pivot Shift test may be used to diagnose an ACL injury. If necessary, you may be referred for imaging. X-rays and MRI can be helpful in diagnosing an ACL injury and in determining the severity of the injury.
How is an ACL injury treated?
The goal of physiotherapy is to restore range of motion and strength of the injured knee, returning function and stability of the joint. In the acute phase, ice and TENS may be used to reduce swelling and pain of the knee, as well as range of motion exercises to reduce joint stiffness. With decreased pain and swelling, your physiotherapist will begin strengthening the injured knee. This will typically begin as isometric exercises and progress to eccentric and eventually concentric exercises. The quadriceps and hamstrings will be targeted as stabilisers of the knee joint. If you are returning to sport, sport-specific and plyometric exercises will be prescribed to make sure you are ready to return. At this point, you should be able to complete all your normal activities, without fear of re-injury.