Anterior Cruciate Ligament (ACL) Tear
An ACL tear is a rupture of the fibrous tissue connecting the thighbone (femur) to the shinbone (tibia).
ACL injuries occur when bones of the leg twist in opposite directions under full body weight.
Injured ligaments are considered "sprains" and are graded on a severity scale
The ACL is slightly stretched but is still able to stabilize the knee joint
The ACL is stretched to the point where it becomes loose. This is referred to as a partial tear.
This is referred to as a complete tear. The ligament has been split into two pieces.
ACL tears are mostly seen in high-intensity dynamic sports that consist of:
Change of direction
Jumping and landing
Contact or collisions
Signs and Symptoms
Complete ACL tears usually result in a loud "pop" at the time of injury followed by rapid swelling and severe pain that diminishes over time.
A comprehensive physical exam is done in clinic. The exam consists of tests that measure the stability and strength of the knee joint.
If the findings on the physical exam are indicative of an ACL tear a Magnetic Resonance Imaging (MRI) may be ordered for further evaluation
Mayo Clinic Staff (2019, March 30). ACL Injury. https://www.mayoclinic.org/diseases-conditions/acl-injury/symptoms-causes/syc-20350738
Anterior Cruciate Ligament (ACL) Injuries (2014, March). https://orthoinfo.aaos.org/en/diseases--conditions/anterior-cruciate-ligament-acl-injuries/