RTPlay Following ACLR - How Do We Know When Is The Right Time? - Part V

Throughout this blog, we have been discussing the need to have a more standardized and objective measures for returning athletes to play (RTPlay) following anterior cruciate ligament reconstruction (ACLR).  Current standard of practice is often reliant on time based criteria and/or some somewhat subjective measures taken at the end point of rehabilitation.  One test that is often used in making this determination on RTPlay or not is the bilateral vertical drop jump (VDJ) test.  Last week, we discussed two recent studies (Krosshaug et al Am J Sport Med 2016, Noehren et al Orthoo J Sport Med 17) that highlighted the challenges with this test and the predictability for risk. 

We also looked at the Rohman et al Am J Sport Med 15 which laid out which single limb tests we should use to determine RTPlay.  These were:

• Single leg squat
• Single leg hop
• Cross over hop
• Timed hop.

However, the majority of these single limb tests are scored visually and hence still lend themselves to some subjectivity.  Some have gone to the use of video based technology where the practitioner will film the athlete performing these tests then try to score based on the video review.  Although this is often provides more information than what we might see in visual observation, it is still somewhat of a subject measure of movement. 

A great example of this is a recent study by Wren et al Orth Sport Phy Ther 2018.  In this study the authors looked at 46 athletes that were 5-12 months post op ACLR.  The authors used the single leg hop for distance test to assess the athlete's limb symmetry index (LSI) at the time of testing.  In this test the subject would stand on one foot with their toes behind a line marked on the floor. The subject would hop forward as far as possible, landing on the same foot from which you took off.  The distance for each jump was measured and recorded in centimeters (cm).  In addition, each subject also performed the test while capturing their lower limb mechanics via a Vicon motion capture system.

The authors compared the distance in meters of the involved to the uninvolved side looking for an LSI of 90% symmetry.  In addition, they also compared data captured via the Vicon system for each subject.  The authors found some interested results:

• Both the groups that had LSI >90% and those that did not tended to offload the non-operative knee.  Meaning they would subconsciously or consciously perform worse on the non-operative side in order to achieve 90% LSI.
• Although subjects had 90% LSI on the single leg hop for distance, this was not indicative of whether or not there was faulty biomechanics in achieving those results. 

Looking at both of these results makes realize that the way we are measuring this today is still not sufficient.  If a subject can perform the tests that are determined to be a part of the standard of practice and still pass those tests by under performing on the non-operative side and with faulty mechanics, then is this sufficient.  In other words, whatever we use we have to have a way of measure the mechanics during these tests.  If we know that it is the amount of frontal plane motion that occurs at the knee and the speed at which this occurs during these tests that puts the athlete at risk, then we must somehow find a way to measure this.  

Although the Wren et al study only looked at one test in isolation, we can assume we would get similar results when looking at other tests or a battery of tests.  As Rohman et al suggested, when testing an athlete for return to play, this should include a series or battery of tests.  If the criteria is that the athlete achieve 90% or > LSI on this battery of tests, what is the likelihood the athlete will pass?

That is exactly what our next study looked at.  Next week, we will look at study by Toole et al 2017 where we get some insight into how many athletes pass a single functional test or battery of tests.  If you enjoy this blog, please share with your colleague and follow us on instagrm @ bjjpt_acl_guy and twitter @acl_prevention.  #ViPerformAMI #ACLPlayItSafe

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent has also been training and a competitive athlete in Brazilian Jiu Jitsu for 5 years.