ACL – What Is That?

Published: 29 Jan 2016

ACL – What Is That?

What is an ACL?

ACL stands for anterior (front) cruciate ligament. You can see it in the picture below. This ligament provides 85% of the restraining force to anterior tibial displacement at 30 degrees and 90 degrees of flexion. What on earth does this mean? When the knee is bent at some positions, the ACL limits the tibia (the shin bone) from gliding too far forward. The ACL also restricts rotation of the thigh and shin bones.

ACL Physiotherapy Penrith

ACL tears are one of the most common knee injuries (here are some others). About 80% of sports related ACL tears are “non-contact” injuries. They occur most often when pivoting on a fixed foot, landing from a jumping or cutting or changing directions sharply and quickly.

Most sports require you to have a functioning ACL. In some cases, patients can avoid having surgery if they are able to return to their normal daily activities with minimal pain, discomfort and instability. HoACL Physiotherapy Penrithwever, returning to high demand sports usually requires surgical reconstruction of the ACL and then extensive rehabilitation.
The main symptoms of an ACL tear are feeling or hearing a “pop” in the knee. This will usually be followed by the knee giving way. Some tears do not have immediate swelling, others can swell immediately and can also be extremely painful. The pain and swelling is usually correlated to the area at which the ACL has been torn and whether there has been any damage to the tibia.

What to do if you suspect you have injured your ACL?

All the physios here at The Healthy Body Company are well trained in assessing for ACL injuries. With most of us doing on-field sports physio coverage we have seen our fair share of knee ligament injuries. If you suspect you’ve done your ACL you should:

  • stop playing,
  • try and reduce the weight through your knee (crutches or someone to lean on if that’s all that is available),
  • apply compression to the knee with a firm bandage,
  • ice the knee and
  • have it assessed.

We can refer for MRI’s if required and discuss the best management plan moving forward to suit your individual needs.

Hopefully we aren’t seeing too many ACL tears, and everyone has a happy and healthy summer.


Jude Holroyd is the Principal Physiotherapist at our Jordan Springs practice – and has seen more than his fair share of ACL injuries in his time.