Anterior Cruciate Ligament (ACL) Tear

The knee joins your upper leg bone (the femur) with the lower leg bone (the tibia) in a joint that's strong and flexible. Four ligaments hold the two bones in the proper positions relative to one another, and the Anterior Cruciate Ligament or "ACL" is one of them. Because of the many forces at work on the knee, ACL injuries arise from a variety of causes. These injuries can include full or partial tears of the ligament itself; separation of the ligament from one of the bones it's anchored to; or a separation that actually takes a piece of the bone away with the ligament.

ACL injuries can be sudden and unmistakable; you may have seen an athlete crumple to the ground in full stride, and speak later of the telltale "pop" sound the knee made. Symptoms include pain and swelling, a lack of support or your lower leg may move forward in relation to your upper leg.

Depending upon the type and severity of the injury, ACL problems can be treated with physical therapy, braces or surgery. In active individuals, tears are best treated with surgical reconstruction. Significant rehabilitation is required in many cases.

Normal ACL	Torn ACL	Reconstructed ACL