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Three factors that determine successful ACL injury rehab

Tearing an ACL is one of the worst fears of any athletes. Here are three critical factors to determining the speed and success of your recovery.

As I've recently realized from personal experience, tearing your ACL can be quite painful. Obviously, there is the knee pain, swelling, buckling, and decreased ability to walk that go along with the acute injury. The physical pain, although unpleasant, usually lasts only a couple of weeks. What can be more problematic, however, is the mental and emotional pain that goes along with the injury.

Why did this happen to me? Do I need surgery? Am I going to be able to work again? Will I ever be able to play sports again? If so, when? Am I at risk for this happening again in the future?

These are just a few of the questions that people have for me when I am counseling them about treatment options for their ACL injury. My goal as a physician is to make sure that the patient has a stable and painless knee that allows them to perform activities of daily living. My goal as a sports surgeon is to try and get the athlete back to playing sports as quickly as possible.

Probably the hardest question for me to answer is exactly when and in what capacity a patient will be able to return to sports after an ACL surgery. The three main things that dictate when an athlete is ready to return to sports after ACL surgery are: ACL healing, strength and flexibility, and confidence.

ACL Healing

One of the first things that must happen for an ACL surgery to be successful is for the new ACL graft to heal and incorporate into the knee. The biology of ACL healing is pretty complex, but basically the tissue and cells of the new ACL graft need to "heal into" and become part of the knee just like the old ACL was. This healing process may be affected by things such as patient age, graft choice, and overall health of the patient. Complete healing of the new ACL can take up to 12 to 18 months; however, after about 6 months or so, we tend to think it's healed enough to allow resumption of athletic activity. Unfortunately, there isn't anything that we can do to speed this process up.

Strength and Flexibility

Obviously, the actual surgery is an important part of an ACL reconstruction. But what is just as important are the several months of rehabilitation that occur afterwards. The event that caused the injury and the surgery itself are very traumatic to the knee and cause the thigh muscles to get weak and not contract appropriately (quadriceps atrophy). A supervised physical therapy program is vital regaining quadriceps function, strength, and control. Therapy is also critical to strengthening other muscles such as the core, calf, and hip rotators.

In addition, maintaining flexibility in the muscles and tendons of the lower extremity is of equal importance. Often, the surgeon will prescribe a step-wise, progressive regimen to be followed by the patient while they are progressing through therapy. Depending on the surgeon and the individual, supervised therapy may be required for up to 3-4 months, with a home exercise program and strengthening being encouraged until return to sport.


The importance of the mental aspect of return to play after an ACL surgery should not be underestimated. Adrian Peterson was able to return to the Minnesota Vikings seven months after ACL surgery and almost broke the single-season rushing record. On the other hand, Derrick Rose was unable to return to competitive basketball even one full year after his ACL surgery.

Both of these athletes are young, extremely athletic, and have incredible work ethics. They both had enough time to allow for graft healing and hundreds of hours of physical therapy. Then why the difference in their ability to return to play? When Derrick Rose was recently asked why he hasn't returned, he said that he 'didn't feel confident.'

This feeling of confidence isn't anything that you can teach or get from more hours in the rehab gym. It's something that is individual-dependent and depends on many factors. Some athletes regain their confidence quicker than others. Regardless of how long it takes, the athlete will not be able to return to their sport if they don't have the confidence to do so.

Read more Sports Doc for Sports Medicine and Fitness.