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A torn anterior cruciate ligament (ACL) is a serious knee injury, especially for athletes. Many teens with a torn ACL will need surgery to repair it.

What Is ACL Reconstruction?

A torn ACL usually is treated with a procedure called an ACL reconstruction. Surgeons replace the damaged ligament with new ACL graft tissue — either taken from the patient's own body (tissue from the main patellar tendon or the hamstring) or donated from someone else (called an allograft).

How Is ACL Reconstruction Done?

Most ACL reconstructions are done under general anesthesia. So you'll be asleep during the surgery and not feel anything. The surgery usually takes 2 to 2½ hours, and you won't need to stay in the hospital overnight.

To do the reconstruction, the surgeon will drill bone tunnels into the tibia and the femur, remove the torn ligament, then place the ACL graft in about the same position.

What Happens After ACL Surgery?

After the surgery, you'll go home with a large bandage covering the knee, a knee brace, crutches, and, possibly, a cold therapy device (a type of continuous cold pack that wraps around the knee). You'll use the crutches to get around so you don't put too much weight on your leg for the first week.

What Is Recovery Like?

Physical therapy is an important part of your recovery. You'll start PT about a week after surgery and continue for the next few months. The physical therapist will help you put more and more weight on your leg until you don't need the crutches anymore.

You also might use a CPM (continuous passive motion) machine that slowly bends your knee back and forth. This helps you get back in the habit of moving your knee.

When your thigh muscles regain their strength (usually about 2 to 3 weeks after surgery), you'll be able to stop wearing the knee brace.

When Can I Get Back to Normal Activities?

Most ACL reconstructions are successful at stabilizing the knee and restoring the ligament's functionality. Patients usually can return to sports and other activities about 9 months after surgery.

If you return to soccer or other sports, the surgeon will fit you with a functional ACL brace to wear during games and practices.

Medically reviewed by: Alfred Atanda Jr., MD
Date reviewed: June 2017