ACL Reconstruction, Rehabilitation and Return to Play

“I TORE MY ACL!” This is, unfortunately, not an uncommon cry from athletes in 2020. In fact, one of the most common knee injuries amongst all athletes is an ACL injury. If you remember from our knee post  the Anterior Cruciate Ligament (ACL)  is one of the mighty four ligaments in the knee that is responsible for stabilization (see figure below).

The ACL prevents excessive back to front motion of the tibia on the femur and rotation of the tibia outwards.  When there is an ACL tear, the ACL is unable to prevent these motions and the knee will often feel unstable. This instability will typically be felt during pivoting and jumping activities.  Some people, however, may have instability with everyday activities, completely disrupting their normal routine.


For the majority, an ACL injury results in a reconstruction surgery. The surgery however is very effective with positive results; after rehabilitation the individual can return to normal activities and their sport, whatever it may be.


However, the million dollar question remains: when is the perfect time to release an athlete back to their sport in order to lower the chance of re-tearing the ligament?

Pre-professional and pro athletes’ coaches, team owners, managers, and ultimately anyone involved in sports would love to finally know the answer. Unfortunately, recovery speed is unique to every individual and there are always outliers, but research helps us understand some trends and find a common ground.

In two separate studies, Paterno and collegues showed that 23.5% of young, active patients suffered a second ACL injury in the first 12 months after returning to their sport following ACL Reconstruction and 37.5% suffered a non-contact re-tear within 24 months after the initial reconstruction. Overall, once an athlete undergoes one ACL reconstruction, they are 4 times more likely to re-tear the ligament again. This study also found that their subjects were 30-40 times more likely to get injured again compared to the athletes with no prior injury.

Many studies assert that in order to lower the chance of retearing the ligament, an athlete should meet this criteria:

1) A specified time away from the sport, usually at least 9 months, is recommended post surgery.

2) Symmetrical muscle function (tested by functional testing guidelines including single and double leg hops).

3) Symmetrical quadriceps strength at the time of return to sport.


Is symmetrical muscle function absolutely necessary? As recent as February 2020, appearing in the Journal of Orthopaedic and Sports Physical Therapy, a study by Beischer and collegues suggested symmetry may not be an absolute. With a sample of 159 athletes, between the ages of 15 to 30 years old, there was no association between sustaining a subsequent ACL injury and achieving symmetrical muscle function or quadriceps strength.

However, their results did show that the athletes who returned to their sport before 9 months after ACL reconstruction surgery are 7 times more likely to sustain a new injury compared to those who delay their return.


Thus, the question remains: what are some of the ways to possibly lower the reinjury percentage?

One conclusion is that 9 months seems to be the earliest an athlete should even consider going back to playing. Every month after that 9 month mark lowers the chance of re-tearing significantly for up to 24 months after. Although quadriceps and hamstring strength, muscle and functional symmetry are crucial parts of post ACL reconstuction rehab, it does not remain consistent with research in terms of lowering re-injury percentage. One of the most consistent facts across most of studies done on this topic is that prolonging the return to sport lowers the chance of retearing and reinjuring the ACL.

While every athlete wants to return to playing ASAP, rushing back could be extremely detrimental. No one wants to increase the chance of sustaining long term injuries. That’s why proper sports rehabilitation is an essential part of any recovering athelete’s career and overall physical health.

Are you recovering from a sports related injury? Let our Doctors of Physical Therapy help as Sports Injury Rehabilitation is one of our specialties. Call BeneFIT Physical Therapy in Chester ( 908.879.5700) or Bridgewater ( 908.203.5200) to schedule your free medical screening.

We take CDC reccommendations of cautious and meticulous sanitizing and sterilizing the facility and equipment, wearing masks and gloves, so that our patients are comfortable and safe during their time at the clinic. We also offer Telehealth visits, so you can have physical therapy via live video chat with one of our therapists without leaving home.

As this is a time of crisis with COVID-19 abound, and the CDC and the state of NJ advising those at risk with weakened immune systems to keep social distancing and in some cases stay at home completely,  health insurance companies are covering telehealth visits for Physical Therapy. Which is great news so people can begin or continue their Physical Therapy. If you have any questions, please call or email us at