Anterior cruciate ligament injury may involve a complete or partial tear within the substance tear of the ligament or an avulsion from the bone.
Page updated July 2023 by Dr Sheila Strover (Clinical Editor)
Sherman Type I ACL injury - the ACL has torn off at the bony attachment site in the roof of the notch.
Sherman Type IV ACL injury - right through the mid-substance of the ligament.
Mechanism of injury of the ACL
A common mechanism of injury is sudden pivoting on that leg when the foot is on the ground and the weight on the same leg.
How is a torn ACL diagnosed?
Firstly there will be a high index of suspicion - the patient may have had a high momentum injury, heard a loud 'pop!' and been unable to walk after the injury. The knee may have immediately swelled up, and even after some days of rest the knee may feel unstable.
The clinician may test for laxity, classically using the 'anterior drawer' test. Laxity may also be tested objectively with an instrument such as the KT-2000
Can a torn ACL heal on its own?
A partial tear of the ACL can heal on its own if the knee is protected from further damage. Once fully avulsed or torn, the ACL is likely to require surgical repair or reconstruction.
Quick links
Forum discussions
- NO Pain and NO Inflammation: ACL/MCL Injury?
Several experienced ACL patients discuss how it is possible to tear the anterior cruciate ligament and not suffer severe swelling and pain during and after the incident.
- ACL and Meniscus surgery all at once -- or separate?
Different patient experiences about prioritising surgery for separate instabilities.
Peer-reviewed papers
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Quote:
"The effects of the timing of ACLR [ACL reconstruction] surgery on postoperative knee function and clinical outcomes continue to be heavily debated. Early ACLR may reduce postoperative complications in patients with ACL deficiency, whereas elective delayed reconstruction can decrease the risk of knee fibrosis and improve clinical results."
Citation: Shen X, Liu T, Xu S, Chen B, Tang X, Xiao J, Qin Y. Optimal Timing of Anterior Cruciate Ligament Reconstruction in Patients With Anterior Cruciate Ligament Tear: A Systematic Review and Meta-analysis. JAMA Netw Open. 2022 Nov 1;5(11):e2242742. doi: 10.1001/jamanetworkopen.2022.42742. PMID: 36394870; PMCID: PMC9672975.
There is currently no content classified with this term.
Classification of cruciate tears -
Tests for cruciate integrity -
Cruciate surgery -
PCL injury -
2017 - 
2017 - ACL injuries in female athletes - by by Ms Michelle Boucher (Clinical Editor)
2011 - Injury to the anterior cruciate ligaments - why timely intervention is important - by Prof Adrian Wilson (Knee Surgeon)
2008 - Predicting the need for ACL reconstruction - by Dr (Mr) Ramakrishnan (Ram) Venkatesh (Knee Surgeon)
2006 -