All About ACL Injury

Paul Bellamy is an experienced musculoskeletal physiotherapist located in South Hurstville at Formation Physio. Today he talks about anterior cruciate ligament (ACL) injury and how they occur.

What is the ACL?

The anterior cruciate ligament (ACL) is one of the main stabilising ligaments of the knee, attaching posteriorly to the lateral femoral condyle and running anteriorly to attach on to the inter-condyloid eminence of the tibia and the medial meniscus. Its role is to prevent the joint from abnormal anterior translation of the tibia and rotational forces.

How do they occur?

ACL injuries are very common in sports that involve pivoting, decelerating and jumping. Popular Australian sports where ACL injuries are common include rugby league & union, AFL, soccer, netball, basketball and OzTag. 

Non-contact ACL injuries account for roughly 70% of ACL injuries vs 30% of contact injuries. Non-contact injuries means that there is no external force applied to the knee for the ACL to tear. It normally occurs when an athlete plants their foot to cut/pivot/decelerate generating enough rotational force in the knee for the ACL to tear. 

Contact ACL injuries normally occur when an athlete is weight bearing and there is an external force to the knee from either a lateral or posterior direction causing rotation or an anterior translation of the tibia.

Risk Factors

It appears that females tend to have a higher incidence rate of ACL injury than males, that being between 2.4 and 9.7 times higher in female athletes competing in similar activities