The ACL is one of four major ligaments (ligaments connect bone to bone) of the knee joint that coordinate function and promote stability of the knee joint. It runs in a notch at the end of the femur (intercondylar notch) and originates at the back part of the femur (postero-medial aspect of the lateral femoral condyle) and attaches to the front part of the tibia (tibial eminence). In the knee, the ACL prevents forward movement of the tibia. It also provides roughly 90 percent of stability in the knee joint.
The classic ACL injury occurs during a non-contact event usually when decelerating, stopping suddenly, twisting, cutting, or jumping. Often the patient will hear or feel a "pop" at the time of injury and sometimes they may report brief a hyperextension of the knee joint. Just after the injury some patients may be able to continue activity; however, most patients are unable to continue regular activity. A few hours after injury, the knee will swell considerably.
When the ACL is injured as a result of direct contact, football is often the associated sport. Most often, the knee is subjected to a direct blow to the lateral side and other ligaments are injured in addition to the ACL. The most common multi-ligament injury is the "unhappy triad" that includes the ACL, medial collateral ligament (MCL), and the medial meniscus.
Our Approach to ACL Tear
UCSF is committed to helping patients with anterior cruciate ligament (ACL) tears return to the highest level of activity possible, whether that means a daily walk or reporting for practice with the NFL. Our team includes orthopedic surgeons, primary care physicians trained in sports medicine, physical therapists and athletic trainers. These specialists work together to tailor a treatment plan to each patient's needs and goals.
Many patients choose to treat an ACL tear with surgery followed by physical rehabilitation. Our orthopedic surgeons are experts in endoscopic ACL reconstruction, a minimally invasive procedure in which small instruments and a thin, flexible medical device with a camera pass through an incision the size of a Band-Aid. After surgery, our physical therapists guide each patient through a personalized rehabilitation program to restore strength and mobility.
Awards & recognition
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One of the nation’s best in orthopedics
UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.