Anterior Cruciate Ligament Tear (Torn ACL)

  • Medical Author:
    Benjamin Wedro, MD, FACEP, FAAEM

    Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

How long does it take to recover from a torn ACL?

Rehabilitation and return to normal function after surgical repair of an ACL tear can take six to nine months. There needs to be a balance between trying to do too much work in physical therapy returning strength and range of motion and doing too little. Being too aggressive can damage the surgical repair and cause the ligament to fail again. Too little work lengthens the time to return to normal activities.

What is the prognosis of a torn ACL?

Most people who have surgery to repair their ACL have good return of function and lifestyle. Long-term success rates are reported between 82%-95%.

Fewer patients develop permanent knee instability. Up to 8% develop graft failure or instability.

For patients who do not have surgery to repair a torn ACL, only half have a fair outcome with no knee instability. This is an option for sedentary people or for those whose activities require no pivoting or cutting.

Is it possible to prevent ACL tears?

ACL injuries usually occur in active people engaged in activities that are enjoyable. The risk of injury can potentially be decreased by maintaining muscle strength and flexibility. Warming up, stretching, and cooling down are ways of protecting joints and muscles.

Wearing braces to prevent injury may or may not be useful.

Strengthening exercises and agility drills can help prevent injury.

Plyometric exercises to help build power, strength, speed, and balance can teach the body how to jump and land properly to minimize the risk of injury, especially in women. It is important to avoid landing on a fully extended and locked leg.


American Academy of Orthopedic Surgery. Management of Anterior Cruciate Ligament Injuries. Evidence-Based clinic Practice Guidelines, 1st Edition. September 2014.

Buchholz, R.W., et al. Rockwood and Green's Fractures in Adults. 6th edition. Philadelphia: Lippincott, Williams and Wilkins, 2006.

La Bella, C.R., et al. "Anterior Cruciate Ligament Injuries: Diagnosis, Treatment, and Prevention." Pediatrics 133 May 2014: 5.

Medically Reviewed by a Doctor on 3/18/2016

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