ACL Injuries

What causes an ACL injury?

The anterior cruciate ligament (ACL) is like a tightly braided rope that connects the shinbone (tibia) to the thighbone (femur). It acts as a stabilizer to help prevent the shinbone from sliding forward beneath the thighbone. When the knee undergoes a severe twist from pivoting for instance, or excessive pressure, the ACL can tear. With a ruptured ACL, the knee can feel wobbly and may easily become unstable. Unfortunately, the ACL does not heal from a tear, or even a partial tear, on its own.

Common causes of ACL tears

Each year, at least 1 in 3,000 Americans between the ages of 14 and 55 tear an anterior cruciate ligament while exercising or playing sports. Skiers, as well as basketball, soccer and football players, are more likely to rupture their ACL, although risk for this injury in not limited to a particular level of athlete or age group.


An estimated 100,000 ACL reconstructions are performed annually in the United States. According to the American Academy of Orthopaedic Surgeons (AAOS), ACL reconstruction is recommended for individuals who want to continue to play tennis, ski, or participate in other sports, or whose knee is unstable during normal daily activities like walking or climbing stairs. A reconstructed ACL not only stabilizes the knee, but also prevents damage to the menisci cartilage that often occurs due to an unstable joint.

Surgeons use part of the patient’s own tendon or a cadaver tendon to reconstruct the ACL. This surgery is often done arthroscopically and has a 95 percent success rate. It is important that the patient follows surgery with a physical therapy program designed to strengthen the quadriceps muscles and restore mobility.

The videos below will give you a general overview of some ACL repair procedures, however, actual surgeries may vary depending on an individual’s  condition.

Torn ACL – Allograft Graft Procedure

Torn ACL – Hamstring Graft Procedure

Torn ACL – Bone-Patellar Tendon-Bone Graft Procedure

Click here to schedule an appointment with an ACL repair specialist.

Illustration reproduced with permission from Fischer S, (interim ed): Your Orthopaedic Connection. Rosemont, IL, American Academy of Orthopaedic Surgeons. Available at