ACL Injury & Re-Injury – Why Are Outcomes So Poor?

We have the technology to measure force output or eccentric deceleration on each limb, access to vast amounts of research, improved surgical techniques, you name it. Yet, the rate of ACL tears and subsequent re-tears is rather high for something we focus so much attention on. And while this is an evolving process, we need to continue to ask questions and learn along the way.

The standard recommendation, which appears to be relatively safe, is waiting 9 months before returning to sport. However, newer research shows that motor deficits may last for up to 2 years and increase the risk of re-injury. Would it be safer to extend it? Yeah, probably, but not all athletes have that time, so there’s pressure and demand to come back quickly and (relatively) safely. Can coaches/therapists do better? Yes.

You fix one little ligament and may not be ready for 2 years!? They put in a nice, strong graft and it ruptures again? Why? Because the whole is greater than the sum of its parts! This should tell you that it’s not just about a single ligament and making sure its back in place. This is not just getting a stronger quad. These are all tiny pieces of the equation. This is the problem with overly reductionist thinking in regards to a complex system (the human body).  That’s where the car and human analogy utterly fails you. If a car needs new breaks, change them, and drive off. Good luck running off the operating table after that new ACL! We are the result of millions of inter-dependent processes and reactions occurring every second.

Based on AI and all previous indicators, we were supposed to have a market crash for the last 3 years. Each time, proving that those indicators weren’t quite right. Then we get hit with something, wait for it…that nobody predicted, which causes a correction and throws society in a tailspin. Because the market, much like human body, is a complex system aka non-linear and thus, unpredictable.

Here’s some interesting research

• “Overall incidence rate of second ACL within 24 months was 6x greater than that in healthy control participants.” [1] “Athletes within the ACLR group were twice as likely to suffer a contralateral injury vs. ipsilateral”. [1]
• “30% of those who had their ACL repaired tore either their graft or opposite side within 2 years.” [2]
• “878 patients under 35 found a rate of re-injury of 62% for men and 40% for women to either knee. [3]
• Of 121 young active adults 62 got surgery and 59 went rehab only. Only 50% of the rehab only group ended up needing surgery and the follow ups showed [4]
• We also now have case reports of athletes returning back to sports in 8 weeks with no surgery [5]

These are thoughts of mine interspersed with research and acquired knowledge through experience in these situations.

• There is a genetic component to the injury-rehab-performance matrix. You work with enough people and you will see this quite clearly. Some people get better each session, some don’t. Some are prone to injury, others aren’t. Some can handle high loads, others are constantly exceeding their ability to recover. This is why trying to predict injuries is futile. It ignores the extreme variability between people and the movements we make. Look at at each person as a unique situation and be comfortable not being 100% certain.

• Girls are more prone to ACL tears statistically speaking. There’s a lot to uncover here. Obviously it’s about more than Q angles! Hormones play a role as it appears that birth control may be somewhat protective, meanwhile there’s enhanced laxity in the joints during the ovulatory phase [6]. We also know that estrogen can decrease the stiffness in ligaments and tendons, which isn’t quite performance enhancing or protective. [7] Quite the opposite. This may help you direct their training a bit differently.

• Lack of Fundamental Movement Skills, GPP, and Play. Too much early specialization, too little unstructured play. The numbers on early specialization don’t lie – higher rates of injury and burn out. Makes perfect sense. Youth athletes who aren’t well developed are playing and practicing more than pros. Little time is devoted to exploring movements outside their sport or building relative body strength. The result is a bunch of motor morons who constantly battle overuse injuries, lack sleep, and watch a sport they love turn into a job they sometimes dread…

• The Quadriceps and Hamstring equation. Picking on girls once again, it appears they demonstrate less hamstring strength vs. men which can also make them more prone to an ACL event. From working with tons of youth girls, they often appear to be more quad dominant and lack good eccentric hamstring strength. The hamstrings flex the knee AND extend the hip, train both! And in order to fully develop them, I would recommend exposure to high speed sprinting and strengthening through all the contractions (eccentric/isometric etc.).

• A broken clock is right twice a day. This one is me just thinking out loud. We hear about neuromuscular coordination in this space a lot. How it can help “prevent” ACL injuries or how noticing a “lack of neuromuscular coordination” is a risk factor. We see a picture of RG3 land during his pro day with crazy valgus stress and everyone jumps up to say, “Oh! We knew that was going to happen!” He undoubtedly did “protective” strength training all through college yet got hurt? Is it because he didn’t do a specific exercise or NMT? Who knows? But then you’d also have to be honest and admit all the times you watched someone go into that position and nothing happens. There’s more to this. This is something I think about often.I’m not saying that someone who hits the ground and completely collapses at the hip/knee/ankle joint with poor trunk control is a pattern I want to see or coach. And we know how this disperses force across the joint.
• At the same time, I’ve seen people that I thought “fit the mold” to be prone to knee injuries never get hurt, and those who have no risk factors get hurt. So if we do “Neuromuscular Re-Training” and someone doesn’t get hurt, it worked? If we don’t do it and they don’t get hurt, that worked too, right? Are we sure it’s the training drills? Or is it awareness? Or is it luck? If we alter the path their body clearly prefers, do we open them up to other issues? I don’t have the answers.
• Training environments are often relatively safe and controlled, injury scenarios are not. A sporting event is chaotic, the nervous system is heightened, hormones elevated, and things are happening FAST! Sometimes too fast for mechano-sensory feedback loops to protect joint structures. Perception, anticipation, fatigue, stress, are all tugging at you here.

Things we CAN control.

• We must do a better job in the developmental stage. If you substituted half the practices youth athletes have with quality strength training or some other form of complex, adaptable movement (say, rock climbing), we would be dealing with far less issues down the line.
• Take an actual off-season. It’s not being lazy, it’s being smart. Develop the abilities that diminish during your season. Allow your body to explore other movements.
• Structure training intelligently. Consider the level of intensity of your practices/workouts (high/med/low?) Consider recovery (off days/recovery sessions), ask about sleep and nutrition. Watch with your eyes. Then add it all up. Team looks tired? THAT’S BECAUSE THEY LIKELY ARE! Injuries often happen when players are fatigued as timing of force production can be altered and capacity to tolerate force can be hampered.
• Goddammit just get more good, quality sleep!
• If rehabilitating, please, for the love of god, make sure the athlete is maintaining fitness before they go back. Second, make sure they are actually progressing in your treatment plan. Expose them to high intense efforts and high loads as that is what they are about to be thrown back into.
  

  References

  [1] https://journals.sagepub.com/doi/10.1177/0363546514530088?fbclid=IwAR2kBKoEARBC8do2tOdKTfge0W3U8-20zkbyqRCDstkx1TP-Lc8s6JZ3P30&[2] https://www.ncbi.nlm.nih.gov/pubmed/24753238
  [3] Shelbourne KD, Gray T, Haro M. Incidence of subsequent injury to either knee within 5 years after anterior cruciate ligament reconstruction with patellar tendon autograft. Am J Sports Med. 2009;37(2):246-251.
  [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4299728/
  [5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4422908/
  [6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524267/
  [7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6341375/