

A: No matter what your age, the decision about how best to treat an injured anterior cruciate ligament, or ACL, should be based on the type of activity you’d like to be able to do after treatment, as well as the stability of your knee overall.

Ligaments are strong bands of tissue that connect one bone to another. Your ACL is one of two ligaments that cross in the middle of the knee that connect your thighbone, or femur, to your shinbone, or tibia. The ACL also helps to keep your knee joint stable. When the ACL is torn, it often results in knee pain and swelling. After an ACL injury, some people also have instability in the knee or a feeling that the knee is “giving way” when they attempt to turn quickly or pivot on it.

The purpose of treatment for an ACL injury is to reduce the pain and swelling, restore normal knee movement, strengthen the muscles around the joint and allow a return to full activity. For some people, that can be achieved with physical rehabilitation alone.

Rehabilitation usually involves doing exercises to regain full knee motion, as well as muscle-strengthening and stability exercises. You may need to use a knee brace for certain activities. Rehabilitation without surgery usually works best for people who have a less active lifestyle and whose knee stability steadily improves with rehabilitation.

If you want to participate in activities such as skiing, singles tennis, hiking on uneven terrain, or other sports that require pivoting, cutting, jumping or twisting, then surgery followed by rehabilitation is more likely to be necessary to fix the ACL and ensure stability in your knee. Also, if your knee continues to give way even after you have gone through rehabilitation, then you may require surgery to improve long-term knee stability.

A torn ACL can’t be sewn back together. Instead, during surgery the ligament is replaced with a piece of tissue called a graft. That graft may be a tendon or ligament from another part of your knee or leg. Or, a graft from a deceased donor may be an option.

If you’re in good health, age typically is not a factor in whether to have ACL surgery. Research has shown that with this surgery, older patients can achieve results similar to those in younger patients, without a significant increase in the risk of complications.

A final item to note is that while ACL surgery typically provides improved knee stability, it does not always provide significant pain relief. If chronic knee pain is your only symptom, it may not be coming from the ACL tear. Rather, it’s more likely to be related to another knee condition, such as a meniscus tear or arthritis.

As you consider the best course of action, talk to your doctor about what you hope to achieve with ACL treatment. Your level of activity and knee stability should guide you as you make your decision.

Dr. Diane Dahm is an orthopedic surgeon at the Mayo Clinic.