Returning Athletes to Sport After ACL Reconstruction: What Are We Missing?

One of the most devastating injuries in sports is tearing of the anterior cruciate ligament, or ACL. For starters, it's probably the most fear-inducing injury that we see, as just about every athlete who comes to us with a knee injury expresses relief once we have ruled it out by stating something to the effect of "That's a relief, I was really afraid I tore my ACL".

Why do they have this hypersensitivity towards ACL injury?

It is commonly perceived and accepted that a torn ACL punches your ticket for reconstruction surgery, and brings with it 4-9+ months of rehabilitation and generally means missing an entire season in your sport. It has been reported that approximately 200,000 ACL reconstructions are performed each year in the United States costing an estimated $3 billion US dollars. While it's not a catastrophic injury, to say that it is routine or somehow not as big a deal as it used to be due to the advancements in the science & technology related to reconstruction surgery and rehabilitation is misguided at best. And we then have to ask: given the advances in the fields of surgical and rehabilitation sciences and strength & conditioning, why do we still see such a high rate of ACL injury and why do so few athletes get back to their sport following ACL injury.

Yes, you read that correctly. It seems that in the information age we are inundated with success stories of professional athletes returning the following season after ACL reconstruction 'good as new.' But understand this: the Willis McGahee's & Adrian Peterson's of this world are few & far between. They are the Exceptions, NOT the Rule. They are also generally already physically gifted and in those to cases in particular, they have access to round the clock medical staff tasked with the sole job of getting that athlete back up and performing. Current research shows that, for those athletes who sustain an ACL injury, about 60% of these athletes make a full recovery, less than 60% return to sport, and more than 50% develop knee osteoarthritis (most commonly though these individuals also have meniscus injury which seems to be highly predictive of osteoarthritis development).

For those who aren't too squeamish, and might not be young enough to remember McGahee's injury during the 2002 Fiesta Bowl: result was a torn ACL & MCL for which he underwent reconstruction surgery.

It is interesting that we have so much research into this topic of ACL injury, yet little practical implementation at the clinical level to aid us in achieving better outcomes for our athletes. What is it that is missing? Well, quality for one...

Let's start with what is accepted. In 2015, The Journal of Bone & Joint Surgery published a paper titled The American Academy of Orthopaedic Surgeons Evidence-Based Guideline On Management of Anterior Cruciate Ligament Injuries. This paper is a clinical practice guideline has been endorsed by the National Academy of Sports Medicine (NASM), the American Orthopaedic Society for Sports Medicine (AOSSM), the National Athletic Trainers’ Association (NATA), and the American Academy of Physical Medicine and Rehabilitation (AAPM&R), so arguably an important paper if all of these organizations have adopted it. The paper looks at the level of evidence supporting common clinical recommendations and practices for the work up and management of an ACL injury. While a good start, the results are not impressive. What is glaring is the need for more high quality research to answer these various clinical questions.

Essentially, we have strong evidence for use of a History & Physical Exam, MRI, Reconstruction using single or double bundle technique, Reconstruction using an Autograft from either patellar tendon or hamstring tendon, Reconstruction using Allograft or Autograft (what else would you use exactly, I'm not sure). It appears that the majority of management is based on Limited to Moderate evidence, and more research is needed in order to be able to make stronger recommendations for or against the management strategies we utilize.

With such a seemingly low rate of return to sport, it seems that there is a need for more impactful injury prevention strategies in an attempt to mitigate as much of an athlete's risk as possible. Certainly as you can see from the McGahee video, there is no amount of injury prevention or strength & conditioning programming that were going to prevent that. This was case where positioning of both players, the force of their collision, and the placing of the impact created a mechanism of injury (that I am confident in stating) had almost nothing to do with any modifiable or non-modifiable risk factors for ACL injury. However, the discussion of non-contact ACL injury, which is the vast majority and affects particularly young female athletes is an entirely different discussion. In this context, these modifiable risk factors do matter, and targeted injury prevention efforts coupled with solid strength & conditioning programming can make a difference.

What is also needed is an identification of what exactly is holding back these athletes that don't get back to their sport. Is it a residual deficit in strength or power, and therefore an inability to perform? Is it a lack of proprioception and joint stability? Is it fear of re-injury and an inability to resume prior levels of confidence when engaging in their sport? (As a side, this was big hurdle for me in getting back to jujitsu after rupturing my MCL.) There is continued research efforts being made to answer this question of essentially "What matters most when getting athletes back to sport following ACL reconstruction?" in a paper published in JOSPT in 2012, Lentz et al looked at differences in demographics, knee impairments, and self-report measures between athletes who were able to achieve pre-injury sports participation and those who were not after 1 year following ACL reconstruction. They found that the strongest factors associated with return-to-sport status were self-reported knee function, episodes of knee instability, and knee joint effusion.

"The highest positive likelihood ratio for the yes-return-to-sports group classification (14.54) was achieved when patients met all of the following criteria: no knee effusion, no episodes of instability, and International Knee Documentation Committee Subjective Knee Evaluation Form score greater than 93." (Lentz et al, 2012)

Certainly there are other variables to look at as well. It is said that for many of the professional athletes that do return, there is a significant decrease in their overall performance. They struggle to make the same impact that the did prior to their injury. More discussion needs to had on deciding what the standard should be for return to play criteria, and how do we capture potential gaps in both the physical and psychological variables that my not be fully resolved.