Signs of an ACL tear

An ACL tear often occurs during sports. Generally, most cases occur without contact to another player. In most cases, when an individual abruptly changes direction, he/she might feel that the knee gives out under their weight.

What are the usual signs of an ACL tear?

Popping sound

An individual with an ACL tear typically hears a popping sound at the time of the injury. Many are surprised on how loud this can be and even bystanders can hear as well in some cases.

Even if the popping is not present, some feel an abrupt shift in the joint.

Instability or giving out of the knee

ACL tear

Swelling of the knee joint typically occurs in most cases of ACL tear.

It is important to note that the ACL is vital in maintaining the stability of the knee joint. Once an ACL tear occurs, the joint becomes unstable where it tends to give out.

The instability or giving out might arise with cutting or pivoting motions common in various sports. Nevertheless, in some cases of ACL tear, the instability can arise even with simple movements while walking or moving into a car.

Pain and swelling

Swelling of the knee joint typically occurs in most cases of ACL tear. The swelling is generally large and occurs rapidly, usually in just minutes after the injury.

The swelling that arises with an ACL tear is hemarthrosis where the knee joint contains blood. Take note that the ACL includes a blood vessel inside the ligament that has ruptured at the time the injury occurred which causes the knee to be filled with blood.

The knee pain linked with the tear is prevalent but might differ depending on the impairment within and around the knee joint.


The doctor will also check the X-ray of the knee joint for any possible fractures. In some cases, an MRI is also requested to assess for damage to the ligament or cartilage.

Quick Note / Disclaimer

The material posted on this page on an ACL tear is for learning and educational purposes only. To learn to recognize the signs and how it is managed, register for a first aid and CPR course with Vancouver First Aid.

FACT CHECK–conditions/anterior-cruciate-ligament-acl-injuries/


No comments yet.

Leave a Reply

Captcha * Time limit is exhausted. Please reload CAPTCHA.