What is Success Post ACL Reconstruction?

Did you know that March is officially “ACL Month”?  It is the one month of the year that health care professionals, scientists and those in sports performance & injury prevention have devoted to focusing on this devastating problem in athletics.  If you have read any of our recent posts, you would see the staggering statistics associated with anterior cruciate ligament injuries.  You would also see the numerous studies we have cited that shows that there is not only been an increase in these injuries over the last 20 years but also a significant impact on future risk, joint health, performance and psychological status of the athlete.  So, starting next week and throughout “ACL Month” we will re-publish some of our most read, referenced and tweeted articles for your review during a month intended to bring focus to this devastating injury. 

Unfortunately, despite all the literature (>900 published papers on ACL in 2013) published on this injury and on the mechanisms of non-contact ACL injuries, rates continue to rise.  Why?  We feel this is partly due to the complexity of the issue and the complexity of the solution.  Unlike Ulnar Collateral Ligament tears (UCL tears or Tommy John Surgery) seen in baseball, if you see a rise in these among youth athletics, you can create policies that impact injury rates.  Simply developing policies that limit certain types of throws which place stress on the UCL and by limiting pitch counts, you can significantly impact injury rates.  Both of these reduce the stress to the joint and limits overuse injuries in baseball.  The impact to UCL injury rates is immediate and significant.  Yet, with non-contact ACL injuries, it is not that simple.  You don’t have a certain type of movement you can limit or a policy that can be passed that will prevent the majority of these non-contact injuries.  With ACL injuries, it is a biomechanical issue related with movement and change in direction and hence the complexity of the solution is more involved and yet to be figured out.  Why?

Unfortunately, there is often a disconnect between academia and clinical application.  What is often done in the lab or academic setting (assessments using large expensive biomechanical labs) is often unavailable in the clinical setting or on the field.  So, instead of using expensive equipment in the clinic, many attempt to develop subjective tests that replicate or measure what is being done in the biomechanical lab.  Often this consist of one or two tests that are subjective in nature and from which there is not a sequential elimination of the abundance of factors that lead to risk for injury.  Hence no root cause is identified and without that, training methodologies tend to be more of a shot gun approach rather than individualized to the athlete.  To compound the issue, it is often years before the knowledge gained from the research about what treatments are most effective becomes a standard of practice used in the clinic.  The end result is that when training methodologies are applied, it can be methodologies that are outdated or not up to current research based interventions.   

There also appears to be a disconnect from what academically & clinically is felt to be success and what athletically is felt is success post ACL injury.  A recent publication from the July 2013 issue of the British Journal of Sports Medicine highlights this.  In this study, Lynch et al defined successful outcome after ACL injury and reconstruction.  In this study, the authors set out to establish a consensus of measures that define successful outcomes 1 and 2 years after ACL injury.  In this study the authors surveyed 1779 members of international sports medicine associations.  These members were all health care professionals from various sports medicine associations including the American Orthopaedic Society for Sports Medicine, the European Society for Sports Traumatology and the American Physical Therapy Association. 

Consensus among the members was achieved for six measures in operative and non-operative management of ACL patients.  These include: the absence of giving way, patient return to sports, quadriceps and hamstring strength greater than 90% of the uninvolved, ≥ mild knee effusion and patient reported outcomes between 85-90%.  Although this is a great start and sounds great, it brings up a couple of questions.

·      Patient self reported outcomes are great and vital.  But, some questions remain how reliable are some in athletic populations.  The other challenge with this is that the outcome measure was not consistent across all members, meaning that several different outcome measures were used.  With several different outcome measures being used, all which assess differently and have varying support in the literature, are we measuring the same thing and is this really consensus?  With ACLs, there is not one consistent one used across the spectrum and therefore the comparisons are questionable.

·      There is not one single test mentioned here that tests in a closed kinetic chain.  Open kinetic chain testing is a poor representation of closed kinetic chain function.  The literature clearly states that the best indicator of risk is frontal plane motion of the knee.  Frontal plane motion is directly correlated to adduction moment at the knee and hence indicator of stress to the ACL.  Knowing this is the greatest risk factor and that asymmetry when compared to the contralateral limb is further indication, you would expect this to also be assessed.  Part of the challenge is there is not a way to accurately assess this with a high degree of reliability, validity and sensitivity.

·      Finally, we know only 43% of athletes return to sport at the same level as prior.  We also know from Rugg et al that if you are a college athlete and have had a prior ACL injury, you are 19.6 fold increase risk of re-injury in sports.  So, are the methods we are using to make calls for return to sport correct?  Knowing that only 43% return to the same level, shouldn’t we do some performance measures in making these calls?  At a minimum, shouldn’t we have a standardized way we make these return to sport calls?  Is it really a “successful outcome” if they are returned to sport yet at only 60% of their prior level?

These are all legitimate questions and really highlight the complexity of this issue.  Throughout the month of March, we will re-post some of our favorite ACL posts.  Provocative posts designed to assist us in asking the right questions and hopefully lead us to the right solutions.   Also, please see our video dedicated to the 1M athletes in the US who have ruptured their ACL in the last 5 years. 

About the author:  Trent Nessler, PT, DPT, MPT.  Trent is a practicing physical therapist with 15 years in sports medicine and orthopedics.  He has a bachelors in exercise physiology, masters in physical therapy and doctorate in physical therapy with focus in biomechanics and motor learning.  He is the founder/developer of the Dynamic Movement Assessment™, Fatigue Dynamic Movement Assessment™ and author of a textbook “Dynamic Movement Assessment™: Prevent Injury and Enhance Performance”.  Trent is also associate editor of the International Journal of Athletic Therapy and Training, Member of the USA Cheer Safety Council and