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ACL Return to Sport Testing

Recently, a lot of attention has been paid to re-injury and return to sport following anterior cruciate ligament...

Recently, a lot of attention has been paid to re-injury and return to sport following anterior cruciate ligament reconstruction (ACLR). Unfortunately the results continue to be less than exceptional.

We are often asked by athletes, “When can I return to my Sport after an ACL repair?” NFL running back, Adrian Petersen, has been a model of phenomenal healing that many athletes cross-reference their return to sport against. Adrian returned to full participation as a running back within 6 months and had one of the most memorable stat lines in all the NFL that year. This anomaly of rapid and explosive return to sport at 6 months after ACLR is very rare and can be a misleading measuring stick.

Slow Down

In a recent study, those who returned to level 1 sports had 4.32 x higher ACL re-injury rate than those who did not. They also found that re-injury rates reduced by 51% for each month RTS was delayed until 9 months. For every month after 6 months with these same athletes, ACL tear risk reduced by 24%

Along with these staggering statistics we remind the athletes that they are not Adrian Petersen. Go youtube some of this guys workouts and the things that he is able to do, he is an athletically blessed specimen. Our bodies come in all shapes, sizes, and type of tissue (fast twitch and slow twitch). Secondly, we have to educate the athlete about allowing the ACL graft time to heal. In numerous studies regarding ACL reconstructions, it takes a minimum of 9 months for solid healing to occur with the new ACL graft. Father time is a criterion based parameter that has to be respected and can not be accelerated. ACL grafting takes time as it goes through the biological process for the ACL to fully heal. Whether it is hamstring or patellar tendon grafts, both processes exceed the often cited 6-month return to sport criteria.

Look at the Data

A case series of elite collegiate athletes who suffered ACL injuries prior to and during their college careers continually found difficulty returning to sports participation (Kamath et al., 2014). Of the 35 athletes who had undergone ACLR prior to enrollment in college, the rate of re-operation on the involved limb was 51.4%, the rate of re-rupture of the ACL graft was 17.4%, and contralateral ACL rupture was 20.0% within this population of athletes. Similarly, those who underwent ACLR during college had a 20.4% re-operation rate, 1.9% suffered re-rupture of the ACL graft, and 11.1% of these athletes underwent ACLR on the contralateral limb.

Unfortunately, these findings are not isolated to collegiate athletes; professional (Busfield et al., 2009) and high school athletes (McCullough et al., 2012) alike have similar statistics. Considering these numbers, it points to inadequate or premature return to athletic participation, which may be because we are overlooking important aspects of athletic competition.

ACL Injury: Pre-Disposing Factors

Like with any injury, it cannot be blamed on one thing. Injuries are multi-factorial as well as non-preventable. Luckily, as we continue to learn more about the mechanism of injury, we have developed some strategies to reduce your chance of ACL injuries. Below are key factors have been shown to predispose athletes to injury:

  • Knee abduction angle at landing was 8° or greater
  • Knee abduction moment was 2.5 times greater
  • Ground reaction force was 20% higher
  • Female athletes – 4-5 x more likely to tear and ACL compared to their male counterpart.

Fatigue and the Missing Link

Prior to returning to sport, most athletes should undergo functional testing, but do these tests, done under optimal circumstances, tell the full story or are we missing something? Often times fatigue is overlooked in the lower extremity injury which can lead to the following:

  • Reduced flexion in the lower limb
  • Reduced knee joint moments
  • Increased hip and knee abduction
  • Increased knee rotation

The research shows an obvious decline in movement quality following fatigue, which may place both post-ACLR patients and uninjured controls at risk for injury.

Albert Einstein is often quoted for saying, “The definition of insanity is to continually do the same thing over and over expecting a different result”. If we are to improve these return to sport and re-injury numbers, fatigue cannot be overlooked and must be included in our clinical decision making process.

Return to Sport Decision VS Performance

At Wright Physical Therapy we have created an ACL Return to Sport (RTS) Exam that takes the athlete through research based physical and functional testing. The rules of this exam are: Athlete must be 9 months post-op to be eligible, Surgeon must sign off on the exam. This RTS exam consists of 3 key elements: Physical Exam, Functional Testing, and Results