Updated: Sep 6
The anterior cruciate ligament (ACL) is one of four knee ligaments. There are two ligaments on either side of the knee (collateral ligaments) and two on the inside. The two on the inside cross in the middle of the knee, which is where the name cruciate (cross-shaped) comes from.
The ACL provides rotational stability for the knee. It limits anterior translation (the moving forward motion) of the tibia and internal rotation of the tibia. It is commonly torn when it is pushed beyond the limits in these movements.
The ACL is not only important as a physical stabiliser of the knee, it also has mechanoreceptors that help detect changes in movement, position, acceleration and tension. These receptors help tell out brain what out knee is doing and is able to activate muscles accordingly.
ACL injuries are among the most common knee injuries in the young active population. 70-85% of these injuries are a result of a non-contact mechanism, meaning it occurs without contact with another player. The ACL is usually injured when the knee rotates inwards with a sudden change of direction. There are many sports where there is a greater incidence of ACL injuries; i.e. football, rugby, netball.
As most ACL injuries occur without contact, there is usually a biomechanical predisposition to injury. This might be that on landing your knee falls inwards, or that you planted your foot and rotated on your leg in an unfortunate way. Other factors that may predispose you to injury are joint laxity, lack of strength and co-ordination, female hormones. There are many programs now that are designed to prevent these injuries and target specific movements and muscles to help stabilise the knee. It is much better to prevent a knee injury than rehabilitate an injury.
What happens if you have injured your ACL?
Traditionally in Australia you would undergo an ACL reconstruction soon after injury. Now there are a few more options. These options are dependent on the extent of your injury and other factors such as the position of your torn ACL. The two main options are: surgery and no surgery. Both options require significant rehabilitation to regain muscle strength, mobility, proprioception and neuromuscular control and return to function.
If you were to undergo surgery, it is important to have no swelling, adequate strength and mobility prior to surgery. A good pre-habilitation period will set you up for success post-surgery. Should you choose conservative management, exercises and returning to function are the most vital part of your recovery. It is important that you are stronger, more robust and move better than you did pre-injury. Whether you plan to return to sport or not, the goal is to prevent further injuries!
Physiotherapy plays a major part in all areas surrounding ACL injuries. We work in preventing injuries by improving biomechanics, managing the post injury stage, pre-habilitating the knee prior to surgery and then programming your recovery and rehabilitation.
Have you had an ACL injury and are looking for a personalised recovery plan? The Physiotherapists at The Movement Workshop South Melbourne are equipped to manage ACL injuries. Both Caz and Jessie have both completed extensive professional development courses which detail the most up-to-date evidence regarding ACL management strategies, including the much discussed, Cross-Bracing Protocol.