ACL rehabilitation guidelines based on quality, not quantity.

Current evidence-based guidelines for return to running after ACL injury:
Chances are you, or someone you know has suffered an ACL injury. That’s because they’re the most common sports-related injury. They’re also one of the most commonly researched topics, both for rehabilitation and prevention. One of the most recent studies published developed rehabilitation checklist aimed at ensuring a safe return to running after an ACL injury. These recommendations are:

ACL Guidelines as per Rambaud, A et al (2018)
1. Pain is less than 2/10
2. Knee flexion range of motion is 95% of the uninjured side
3. Full active knee extension
4. No swelling
5. Isometric hamstring and quadriceps strength more than 70% of the uninjured side
6. Single leg hop test more than 70% of the uninjured side
7. Single leg squat or step-up without knee valgus

The theory is that if you’re able to achieve all of the above guidelines, then you're safe to return to running. How long can one expect this process to take? The average individuals will return to running twelve weeks after surgery. How long is the full recovery process? A standard rehabilitation program takes about twelve months. So, why are individuals allowed to return to running a third of the way through the rehabilitation process? Is this really the best option for a safe return?

Revised guidelines based on quality:
Nowadays the ACL rehabilitation process seems to be more focused on returning to running/sport, rather than the quality/performance of the individual. For example, we ask questions like: How long will this take? How long until I can get back on the field? We want results here and now and will do almost anything to speed up the process. The issue with this is that the factor that increases your risk of injury the most is previous injury. If you’ve already torn your ACL, you're four times more likely to reinjury your ACL. This doesnt include the increased risk of injuring your other knee! With shockingly high reinjury rates, it sounds like we should be more focused on quality than quantity. What does that mean? If we take the above guidelines and focus on quality, they would look like this:
(Revised) ACL Guidelines
1. No pain at rest and low-level pain with exercise (<2/10)
2. Full knee flexion range of motion when compared to the uninjured side
3. Full active knee extension range of motion
4. No swelling
5. Isometric hamstring and quadriceps strength more than 95% of the uninjured side (rather than 70%)
6. Single leg hop test more than 95% of the uninjured side (rather than 70%)
7. Single leg squat or step-up without knee valgus

You may think these new guidelines push our expectations. Maybe they're a bit much. But when we’re talking about elite athletes, you wouldn't want your prized player returning to running or even playing at only 70% of their capacity, right? What about the non-elite level athletes? Knowing that the reinjury rates are shockingly high and that you’re 50% more likely to develop osteoarthritis in the injured knee, it might be worth your time to ensure you’re performing at your optimal level.

Pain and range of motion based guidelines:
What if we take this one step further? Rather than hold someone to generalized guidelines, why not make them individual specific? Sure, a few of the abovementioned guidelines are easy to copy and paste to anyone. For example, the guidelines we expect everyone to achieve regardless of sport, activity level, age, etc. would look like this:
(Revised) ACL Guidelines: Pain and Range of Motion
1. Full active and passive knee range of motion compared to the uninjured knee
2. No pain or swelling

Performance-based (strength) guidelines:
Those are the easy guidelines to achieve. The ones we really need to focus on are performance based. Since strength is the mother of all qualities, not only should our expectations be high (95% compared to uninjured side) they should be based on functional tasks. Our performance-based and strength focused guidelines would look like this:
(Revised) ACL Guidelines: Performance-Based (Strength)
1. Isometric, concentric and ECCENTRIC (that's the big one) hamstring and quadriceps strength is 95% or higher compared to the uninjured side
2. Barbell squat and deadlift without knee valgus using weights based on body weight
3. Be able to perform single leg variations of abovementioned exercises without knee valgus

Performance-based (power) guidelines:
Now, the three strength based guidelines are a bit harder to achieve. These are the ones that are going to take time. When we expect the full rehabilitation process to take one year, its because your time is spent developing strength and efficient movement patterns, in the gym and on the field. There are other performance-based goals, that look at things like explosive power. This guideline would look like this:
(Revised) ACL Guidelines: Performance-Based (Power)
1. Single leg hop test (or a test known to be more specific to your sport/activity) performed at 95% compared to your uninjured side

Psychological-based guidelines:
Why are we okay with 70%? When did performing at 70% of your potential or capacity become a good thing, something that's tolerated? Why do I think 95% is better? Being able to perform at 95% of your physical capacity allows for small but allowable differences from side to side. It also allows you to develop confidence after injury. That's why it's important to add in one more guideline focusing on the psychological side of injury and rehabilitation:
(Revised) ACL Guidelines: Psychological-Based (Confidence)
1. Individual reports high levels of confidence and feels they are able/ready to perform

Individualized, performance and psychological-based guidelines:
If you’re not confident with your body’s ability to perform, how likely are you to return to sport/activity? In fact, there’s plenty of research that shows individuals who lack confidence after injury are far less likely to return. An ACL injury is the most common among athletes. It's also one of the most research injuries with regards to prevention and rehabilitation. Unfortunately, the standards and expectations don't match. Guidelines that focus on quality > quantity look like this:
ACL Guidelines: Quality > Quantity
1. Full active and passive knee range of motion compared to the uninjured knee
2. No pain or swelling
3. Isometric, concentric and ECCENTRIC hamstring and quadriceps strength is 95% or higher compared to the uninjured side
4. Barbell squat and deadlift without knee valgus using weights based on body weight
5. Be able to perform single leg variations of abovementioned exercises without knee valgus
6. Single leg hop test performed at 95% compared to your uninjured side
7. Individual reports high levels of confidence and feels they are able/ready to perform

If we start using guidelines that are individual-specific, focus on developing sufficient strength and movement, and ensure the individual feels prepared, we might stand a better chance at reducing the risk of reinjury and further dysfunction.

Dr. Cory Myers

Helping the #everydayathlete increase performance and recovery from injury so they can train hard and stay injury free.