Should I have surgery for an anterior cruciate ligament (ACL) injury?

Introduction

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This information will help you understand your choices, whether you share in the decision-making process or rely on your doctor's recommendation.

This Decision Point does not apply to children or teens: their bones have not stopped developing, so there are different considerations. Nor is this Decision Point for those who have already had ACL surgery and are undergoing revision surgery. In these situations, talk to your health professional.

Key points in making your decision

Surgeons often prefer different types of surgery for anterior cruciate ligament (ACL) injuries based on their experience and training and what they have found to work best. You may want to talk to more than one orthopedic surgeon about your knee injury. If different doctors recommend different approaches for your surgery, choose the surgeon with whom you feel the most comfortable and who has a good reputation in your community.

Consider the following when making your decision:

• Your age is not a factor, although your overall health may be. Surgery may be done for most adults at any age who want to continue activities that require a strong, stable knee.
• Your best chance to have a stable knee and an active lifestyle without further pain, injury, or loss of strength and movement in your knee may be ACL reconstruction surgery followed by a long and intensive rehabilitation (rehab) program. However, this also depends on how badly your ACL was damaged. You might consider reconstructive surgery if:
  • Your ACL is completely torn or partially torn and unstable.
  • You are very active in sports or have a job that requires knee strength and stability (such as construction work).
  • You have long-lasting and recurrent (chronic) ACL deficiency that is affecting your quality of life.
  • You have injured other parts of your knee, such as the cartilage, meniscus, other knee ligaments, or tendons, or broken bones within the knee joint.
  • You are willing to complete a long and rigorous rehabilitation program.
• You might want to wait before trying surgery if you are willing to first undergo several months of rehab to see if it resolves your problem.
• If you wait too long to reconstruct a torn ACL and develop chronic ACL deficiency, the surgeon may not be able to repair all the joint damage, and you may still have pain and swelling. It is important to have surgery before knee instability leads to degenerative changes.

Medical Information

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What are the anterior cruciate ligament (ACL) and an ACL injury?

The anterior cruciate ligament (ACL) is one of four knee ligaments that connect the upper leg bone (femur) with the large lower leg bone (tibia). The ACL stabilizes knee movement by:

• Preventing the lower leg bone from sliding forward or turning when the leg is straight.
• Preventing the knee from being stretched or straightened beyond its normal limits (hyperextended).
• Supporting the knee ligaments that keep the knee from bending sideways.

See an illustration of the knee and the ACL .

An ACL injury can involve a small or medium tear of the ligament, a complete tear of the ligament (rupture), a separation of the ligament from the upper or lower leg bone (avulsion), or a separation of the ligament and part of the bone from the rest of the bone (avulsion fracture). When any of these occur, the lower leg bone may move abnormally forward on the upper bone, with a sense of the knee giving out, and possibly further injuring the inside structures of the knee.

What are the risks of an ACL injury?

The risks of an ACL injury depend on whether you stop or modify activities that require a stable knee, how severe the injury was, whether other parts of the knee also were injured, and whether you undergo and complete a rehabilitation program.

If nothing is done, the ACL injury may develop into chronic ACL deficiency. The knee becomes more and more unstable and may give out more often. The abnormal sliding within the knee also can damage cartilage and trap and damage the menisci in the knee and can lead to premature osteoarthritis.

• If you can live within the limits that a somewhat loose knee requires and avoid repeated episodes of instability, your knee will not necessarily develop osteoarthritis.
• If you repeatedly do things that cause your knee to give way and become painful and swollen, the joint will develop degenerative changes that can become disabling.

If you wait too long to reconstruct a torn ACL and develop chronic ACL deficiency, the surgeon may not be able to repair all the joint damage, and you may still have pain and swelling even though the surgery makes the knee stable again. It is important to have surgery before knee instability leads to degenerative changes.

What are the possible complications of surgery and rehabilitation?

ACL reconstruction surgery is generally safe. Complications from surgery or problems that may arise during rehabilitation and recovery include loss of motion in the knee joint, grating of the knee cap, and pain or swelling during activities ranging from daily activities to strenuous sports.

How successful is ACL surgery?

Between 80% and 90% of people who have ACL surgery have favorable results, with reduced pain, good knee function and stability, and a return to normal levels of activity.¹ Between 3% and 10% of people who have ACL surgery still have knee pain and instability.²

Your Information

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Your choices are:

• Have ACL surgery and take part in a physical rehabilitation (rehab) program after surgery.
• Choose conservative treatment, including rest, exercise, and a rehab program.

The decision about whether to have surgery for an ACL injury takes into account your personal feelings and the medical facts.

Deciding about ACL surgery

Reasons to have ACL surgery

Reasons not to have ACL surgery

You have completely torn your ACL or have a partial tear and your knee is very unstable. You have gone through a rehabilitation program and your knee is still unstable. You have injured other parts of your knee, such as cartilage, meniscus, other ligaments, or tendons, or broken bones in the knee joint. You rely on a strong, stable knee for working or playing sports. You are willing and able to commit time and energy to a long and rigorous rehab program. You have a chronic ACL deficiency that is affecting your quality of life. You are in good health. You have an excellent chance of achieving favorable results with surgery and rehabilitation. ACL repair may be successful for an ACL that has torn away from the upper or lower leg bone (avulsion). Are there other reasons you might want to have surgery for an ACL injury?

You have a minor tear in your ACL, but your knee is stable. You do not need a strong, stable knee for work or sports. You are willing and able to stop doing activities that require a stable knee or to stop doing them at the same level of intensity. You can complete several months of rehab to reduce the risk of reinjuring your knee. You are not willing to commit time and energy to the long and rigorous rehab program necessary after surgery. You have health problems that make surgery more risky. There is a chance that you could be one of a small number of people who still have knee pain and instability after surgery. A second surgery (revision ACL reconstruction) is sometimes necessary. This surgery is generally not as successful as the first surgery. Complications include risks common to all surgeries (such as infection), a limited range of motion in the knee, and pain or swelling during activity or sports. Are there other reasons you might not want to have surgery for an ACL injury?

These personal stories may help you make your decision.

Wise Health Decision

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Use this worksheet to help you make your decision. After completing it, you should have a better idea of how you feel about having surgery for an ACL injury. Discuss the worksheet with your doctor.

Circle the answer that best applies to you.

My ACL is completely torn or torn enough that I have an unstable knee.	Yes	No	Unsure
I depend on a healthy knee for work.	Yes	No	Unsure
I am actively involved in sports that require a healthy knee.	Yes	No	Unsure
I am willing to forgo some of my activities or do them with less intensity.	Yes	No	Unsure
Other than the ACL injury, there is no other damage to my knee and I am in good health.	Yes	No	Unsure
I feel I can commit to and complete a long and intensive rehab program.	Yes	No	Unsure
I understand the risks involved in surgery.	Yes	No	Unsure
I have had my ACL injury for a long time. I sometimes feel pain, and my knee sometimes buckles.	Yes	No	Unsure

Use the following space to list any other important concerns you have about this decision.

What is your overall impression?

Your answers in the above worksheet are meant to give you a general idea of where you stand on this decision. You may have one overriding reason to have or not have surgery for an ACL injury.

Check the box below that represents your overall impression about your decision.

Leaning toward having surgery

Leaning toward NOT having surgery

Return to the topic Anterior Cruciate Ligament (ACL) Injuries.

References

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Citations

1. Fu FH, et al. (2000). Current trends in anterior cruciate ligament reconstruction. American Journal of Sports Medicine, 28(1): 123–130.

2. Noyes FJ, Barber-Westin SD (2001). Revision anterior cruciate ligament reconstruction: Report of 11-year experience and results in 114 consecutive patients. AAOS Instructional Course Lectures, 50: 451–461.

Credits

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Author	Robin Parks, MS
Author	Ralph Poore
Editor	Kathleen M. Ariss, MS
Associate Editor	Michele Cronen
Associate Editor	Tracy Landauer
Associate Editor	Pat Truman
Primary Medical Reviewer	William M. Green, MD - Emergency Medicine
Primary Medical Reviewer	Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer	Kathie Hummel-Berry, PT, PhD - Physical Therapy
Specialist Medical Reviewer	Patrick J. McMahon, MD - Orthopedics
Last Updated	May 19, 2006