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Neurocognitive Training for ACL Rehabilitation and Return to Play Testing

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I have a great guest post on neurocognitive training after ACL surgery by Lenny Macrina. This is an emerging field of research that is starting to show some promise in helping us with our ACL rehabilitation programs, as well as return to play decision making.

Return to play after ACL reconstruction surgery is often a complicated decision-making process. As we have written in the past, numerous studies have shown that return to play testing after ACL reconstruction is not straightforward. With ACL re-tear rates so high, our physical therapy research is still lacking definitive guidelines on the best return-to-play criteria. 

I’m consistently trying to figure out the best methods to allow our patients to return to their sport as safely and effectively as possible.

In this post, I wanted to look at the research on the neurocognitive effects of an ACL tear. This is definitely an emerging field of research that has blossomed the past few years. There are not many studies published on this topic so I hope to better understand and explain what this field is proposing, and how it may impact our return to sport decision making after ACL reconstruction surgery. 

Neurocognitive Changes After an ACL Tear

From what I can see, Grooms et al first talked about this phenomenon in 2015 in a paper in the Journal of Athletic Training. They looked at functional MRI’s of the brain for one ACL-injured participant versus a single matched control participant.  Small sample size, of course, and a pilot study of some sort.

They determined that the ‘ACL-injured participant exhibited increased activation of motor-planning, sensory-processing, and visual-motor control areas. A similar activation pattern was present for the contralateral knee that sustained a subsequent injury.” 

The brain activity was absolutely different than the control matched patient that did not have a previous ACL tear.

Based on this one patient, they concluded that “Neuromuscular training that incorporates visual or neurocognitive processing, such as ball tracking or engaging other players, task complexity (reaction and decision making), anticipatory aspects, and cognitive load (dual-task), can address the possible sensory reweighting of visual feedback for motor control.”

Interventions that integrate sensorimotor feedback with injury reduction programs have the potential to enhance brain functional connectivity to improve ACL injury risk reduction biomechanics.

We already know that neuromuscular programs can help reduce ACL tears, especially in female athletes. There’s a ton of research that shows nearly a 67% reduction in non-contact ACL injuries if these programs are implemented.  But, perhaps by adding a greater focus on visual and neurocognitive processing, we would see an even greater effect. 

Interesting findings… but how can we apply this concept to our ACL physical therapy  programs and return to sport testing to make them even better?

Combining ACL Neuromuscular and Neurocognitive Training

Reactive control and athletic decision making needs to become a subconscious response based on sensory and visual input. An external focus of control is needed to optimize neuromuscular control. 

In an even more simple term, we as rehabilitation specialists need to create rehab programs that integrate the surrounding environment into each program.

This concept is very different from what we traditionally use in many of our cues during an exercise. We often tell people to prevent their knees from collapsing inward.  Sometimes we even use an external force to pull the knee into more valgus to facilitate a neuromuscular response to prevent that movement.

Instead, maybe we need to use a neurocognitive cue and have our patients to perform drills like a RDL toward an external prop like a cone based on randomized cueing. 

Neurocognitive Training for ACL Rehabilitation and Return to Play Testing

It seems similar but using the visual and external input, the brain wiring will be different and potentially allow the athlete to perform this movement subconsciously as their training progresses.

As the person progresses, we can start to combine a visual cue to react prior to beginning a movement. Here’s an example of a simple 3-way hop. But rather than knowing and anticipating the movement, we are cueing the person as to which direction to hop. They subsequently need to react based on the visual stimulus.

We often focus on strength and even neuromuscular control, but by adding an element of visual input and reaction to the direction of the hop, we further challenge the neurocognitive input as well as the neuromuscular output. As you can see here, this professional athlete struggles by trying to anticipate, but then adjusts and improves his reaction. This takes a lot of effort!

This could easily be progressed to include randomized and more complicated cues.

Combing neuromuscular and a neurocognitive training approach may allow a transfer of motor control to subcortical regions and free cortical resources for programming more complex motor actions. This would help to screen out incorrect motor responses by the athlete.

Return to Sport Testing after ACL surgery

By better understanding this information, we can develop return to sport testing guidelines that can better determine readiness and hopefully reduce future injuries even more.

I’m not going to lie, I struggle to have a formal test that solely determines my athlete’s return to sport. 

With that, I wanted to seek out this new research that may help to better determine an athlete’s readiness, both neuromuscularly and neurocognitively.

Neurocognitive Hop Tests to Determine Return to Play after ACL Surgery

I stumbled upon this recent Tweet by Ohio University PT and researcher Dusty Grooms (@Dusty_Grooms) so I clicked on his 2 links to read the articles.

Neurocognitive Implications for ACL Rehabilitation and Return to Play Testing

The articles really made me think about what we are doing with our patients and the role of the brain. I have always thought that the brain plays a much larger role than what we ever imagined. 

I know that we like to focus on ACL graft options, loss of range of motion after ACL surgery, strength training after ACL reconstruction, surgical technique, surgeon, etc but we continually miss the boat. I am certainly not downplaying those variables and still think they are quite important, especially during the early phases of ACL rehabilitation. But there’s a reason why our ACL retear rates are so high. 

This Grooms paper sought to compare the relationship between four foundational single-leg hop tests and their respective neurocognitive single-leg hop test. These hop tests have been shown to be reliable in a previous study from 2019. 

Nine males and 13 females were recruited for this study. They performed the traditional hop test which included a single leg hop, single a crossover hop, single-leg triple hop, and single-leg 6m hop. 

They also performed these tests separately in which neurocognitive conditions were altered in order to compare the two groups.

The hop test for the neurocognitive group utilized a Fit-Light System that signaled when each hop trial was initiated. Signals changed color and were randomly activated to force the athlete to anticipate each hop then respond as quickly as possible.

The hop tests consisted of:

  • Single leg hop – When the correct color flashed, green the participant jumped as far as possible with a single hop
  • Single leg triple hop –  the fit light flashed one of six colors at random each trial, a random color was selected as the Hop color while the remaining five or assigned as do not hop the participant would perform a single leg hop full within three consecutive hops when the correct color flashed.
  • Single leg crossover hop –  the participant stood on a centerline in either hop. Based on if the right or left light flashed in their periphery, the sequence of hops was determined by which light was first seen by the participant.
  • Single leg 6-meter hop at a random time – the fit light would blink either red or green and hop 6m as quickly as possible.

Here is an example of the crossover hop test performed in the study, big thanks to Dusty Grooms for allowing us to use this video:

Neurocognitive Tasks Decreased Hop Test Performance

The addition of the neurocognitive task decreased the performance for each crossover hop, triple hop, and 6-meter hop test when compared to the traditional hop test. 

The only hop test that was not affected was the single-leg hop test when compared to the traditional manner. 

Adding a cognitive challenge resulted in the athletes’ inability to jump as far and as quickly, relative to the traditional hop test. 

These results may have implications for our rehab programs to help us better design a more mentally challenging environment for our athletes.

As they described in the study, “the more complex hop tests were devised to challenge different aspects of visuomotor and cognitive-motor function, as well as increase the complexity.”

Performance declines were affected by environmental stimuli, which may be extrapolated to real-life performances on the field when actions are less rehearsed and more reactive.

Neurocognitive Training for ACL Rehabilitation

I find the topic of neurocognitive training interesting and fascinating. I’m hopeful that what Dusty and others are doing in this field will help future patients’ recoveries. I also think that it will help clinicians to better understand the complexities of post-surgical ACL rehabilitation.

With our ACL outcomes being far from perfect, I feel as if this new field of research could offer potentially promising outcomes once we better understand and implement these research findings into a comprehensive ACL reconstruction physical therapy program.

Physical Therapy or Surgery for a Meniscus Tear?

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Today’s article is a guest post from Lenny Macrina, my co-owner of Champion and co-author of my online knee course.  Meniscal tears are common, and some interesting new studies are coming out showing that surgery may not be the best option, at least for some people.  Social media is quick to shun meniscus tear surgery, however there are likely still some people that will benefit from this more than physical therapy alone.  Lenny discusses more in the article below. But I also wanted to make sure you knew that Lenny and I’s online course on the Evaluation and Treatment of the Knee is on sale this week for 50% off.  More info below!

Meniscus tears are very commonly diagnosed by physical therapists and doctors. The question remains, what is the best treatment for someone with a meniscus tear…surgery or physical therapy?

I may be a bit biased because I am a physical therapist. Let me get that out there right now. I’d almost always advocate for physical therapy over surgery for most of the cases that I deal with. But I do believe we are trying to be too black and white at times and need to keep an open mind.

There are many factors that need to be considered when deciding between physical therapy or surgery for a meniscus tear.  Some people may do better with physical therapy, while others may do better with meniscal tear surgery.

It depends.

With that, I decided to do a literature to see what the latest research is telling us. There’s lots out there and it seems as if the recent studies push for physical therapy as the first line of defense for someone with a mensical tear.

Intuitively, that makes sense but I wanted to dig deeper and see if this was true for everyone, or are there certain people that may benefit more from surgery.

Do You Need Surgery After a Meniscus Tear?

Of course, I went to PubMed because that’s my go to website for the latest in research topics. My search for knee meniscus physical therapy pulled up hundreds of papers, so of course I read them all…ok, maybe not.

I did my best so here goes…

In summary, it seems like there’s pretty good evidence to support that physical therapy should be used early after a meniscus tear in most of the common cases that we see.

There’s a growing body of evidence to try physical therapy first, especially for chronic degenerative meniscus tears. When I say a degenerative meniscus tear, I mean a tear that is probably a bit older and has been chewed up, well beyond repair.

Mensicus Tear Surgery or Physical Therapy

These degenerative meniscus tears are also often associated with knee arthritis, to some extent. Because of this, surgery to help with the associated pain is often limited due to the arthritis, and may not help the patient as much.

A period of active rest to calm the knee down and determine the course of treatment (surgery or more physical therapy) is often employed.

Very rarely is there a case where we should rush in to a surgery unless there’s a gross loss of motion, as in a bucket-handle meniscus tear that is obvious and leading to a disability.

I also think there’s a population of people who will benefit from surgery because they MAY be expecting to have surgery. I know, it’s complicated but that’s why we practice this stuff daily.

It’s not always cut and dry. People are human, and have emotions and opinions.

We can do all of the educating that we want but if they expect to have surgery and WANT surgery then just maybe they may benefit from having surgery. And that group of people may just do well.

Part of my treatment plan early on would be to educate them regarding the surgery, potential complications, some of the research and the post-op course.

All too often people are told that they’ll be back in 4-6 weeks after meniscus tear surgery and we all know that is NOT true. I usually tell people that it will take 4-6 months and even then, they still may not feel right until a year later. Sure, they may be doing some of their activities in 4-6 weeks, but that doesn’t mean they are completely back to normal.

The key is to recognize and find that person during your examination. I previously wrote a blog post on meniscus examination that goes over this in more detail.

Once diagnosed, can you separate out the meniscus tears that truly could benefit surgery from the ones that would do just as good without surgery?

Unfortunately, that’s the complicated part!

In a recent study from 2016, this group found that shorter symptom duration and greater baseline pain may be a predictor of who would qualify for earlier surgical intervention rather than physical therapy. They also suggested that an initial course of rigorous treatment prior to a knee scope may not compromise surgical outcome.

When in doubt, take it to Twitter.

In a recent Twitter discussion with some doctor colleagues of mine, we talked about this same and it was refreshing to hear that many are recognizing the fact that physical therapy may be the better option for most meniscal injuries.

Mensicus Tear Surgery or Physical Therapy

What is the Best Treatment Option for a Meniscus Tear?

Like I said earlier, there’s a bunch of research, so I tried to pick out some that I thought were the best and from highly reputable journals.

This study from the Journal of the American Medical Association showed that among patients with non-obstructive meniscal tears, physical therapy was equal to arthroscopy for improving patient-reported knee function over a 24-month follow-up period. ⠀⠀

They went on to say that “Based on these results, physical therapy may be considered an alternative to surgery for patients with non-obstructive meniscal tears.”

So, basically if there is not a bucket handle meniscus tear present that may be blocking joint range of motion, then it is highly encouraged that the treatment and exercise, and not undergo surgery.

Without going out on a limb, I’d say this is a much cheaper treatment option as well and would greatly reduce health care costs associated with the surgery and lost time from work.

This study from the British Medical Journal looked at the cost-effectiveness of meniscus tear surgery versus nonoperative treatment and showed that surgery was not economically effective and should be reconsidered.

I did note a couple limitations: the surgical group did not get treatment after surgery if they did ‘as expected’ but they could get treatment to help improve their symptoms.

The physical therapy group did pretty basic exercises although leg press, lunges and balance type exercises were included. I would’ve liked to have seen a more robust attempt at treatment that involved more strength training and true progressions for the quads, hip and complete lower body.

Another study that I wanted to discuss was a systematic review that looked at the best treatment options for someone greater than 40 years of age diagnosed with a degenerative meniscus tear.

They showed that ‘the results of this systematic review strongly suggest that there is currently no compelling evidence to support arthroscopic partial meniscectomy versus physical therapy for a meniscus tear.’

There was an issue with the quality of the studies involved in the study, including a high risk of bias, weak to moderate quality of the available studies, the small sample sizes, and the diverse study characteristics.

Furthermore, they said that no conclusion could be drawn as to which treatment was the best option for this patient population. Which I tend to agree, right?

Intuitively, one would say that physical therapy, as the cheaper option, would be the best but I think it goes to my above statements that “it depends” on the person, type of mensicus tear, chronicity of the tear, their symptoms, AND their beliefs.

I think this study from The New England Journal of Medicine basically says the same thing. A course of physical therapy may be good for some but often times surgery may be needed for a select group of people.

This study from the British Medical Journal looked at exercise versus surgery for degenerative meniscal tears in Norway. The mean age was 49.5 years, which is pretty typical, right?

This study also controlled for degenerative tears only and most everyone had no signs of radiographic knee osteoarthritis (96% of the cohort had no definitive radiographic evidence of osteoarthritis).

They showed that middle aged patients with degenerative meniscal tear and no definitive radiographic evidence of osteoarthritis should consider supervised meniscus tear physical therapy as a treatment option over surgery.

What to Recommend to Your Patient, Physical Therapy or Surgery for a Meniscus Tear?

Remember, about 1/3 of the meniscus has blood supply that can help it to potentially heal on its own. We got that information from a paper way back in 1982 and it still seems to apply today.

I don’t think there’s any doubt that physical therapy (swelling control, range of motion, strengthening, education) should be one of the first treatment options in someone that has been recently diagnosed with a meniscus tear.

This seems to definitely be true in the groups of people with a degenerative meniscus tear. They seem to do just as well with early treatment than a more expensive surgical option.

For someone with an acute meniscus tear that is blocking range of motion, such as with a bucket handle tear, then surgery may be indicated right away.

For the younger athlete with an acute meniscus tear, I would potentially consider a surgery a bit earlier but still gives them a course of treatment for 4-6 weeks to see if the symptoms subside and the person can resume their normal function.

So, try meniscus tear physical therapy and hope to see significant changes in the patient’s symptoms and function in the first 4-6 weeks. If no true changes or if they are getting worse (and frustrated), then consider surgery.

After meniscus tear surgery, pick up the therapy where you left off and hopefully get them back to their ultimate goals.

Learn How We Evaluate and Treat the Knee

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5 Keys to Returning to Sport After a Knee Surgery

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The latest Inner Circle webinar recording on 5 Keys to Returning to Sport After a Knee Surgery is now available.

5 Keys to Returning to Sport After a Knee Surgery

This month’s Inner Circle webinar is on 5 Keys to Returning to Sport After a Knee Surgery. In this presentation, I’m going to review some of the statistics regarding return to play rates and discuss some of the clinical implications. Based on this, we’ll review the 5 keys that I think you need to follow to maximize your outcomes and return to sports, while minimizing your chance of reinjury.

This is an updated version of a past presentation on the keys to ACL rehabilitation, but with some newer research and some broader implications that just ACL. I wanted to provide some updated concepts. The ACL talk still has more specific information, so be sure to check that out too

This webinar series will cover:

  • What the latest research is showing about return to play statistics follow knee surgery
  • The two keys you should focus on during the first couple of weeks following any knee surgery
  • How to structure more advanced strengthening into your rehabilitation programs
  • How blood flow restriction training fits into the postoperative rehabilitation process

To access this webinar:

Measuring the Position and Mobility of the Patella

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Measuring the position and mobility of the patella is still a very important component of my clinical examination of the knee.  It gives me a great sense of soft tissue restrictions that may be present when patellar hypomobility is noted.  This is especially common after knee surgery.  But measuring patella mobility is also important to assess generalized laxity when patellar hypermobility is observed.

The first time you feel either of these during your clinical exam, you’ll know what I mean.

But if you read through the literature, you may find conflicting results regarding the validity and reliability of assessing patella position and mobility.

The Reliability of Measuring Patella Mobility

One study that I reference often is a systematic review by Smith, who looked at the reliability of assessing patella position, specifically in the medial-lateral position.  Like any examination technique that is commonly performed, it is necessary to establish that the test has adequate intra-rater and inter-rater reliability. The test needs to be easily replicated and produce accurate results both between two different clinicians but also when repeated during re-evaluation with the same clinician.

Otherwise, the test may have limited use and not be able to provide helpful information.

The authors conclude the intra-tester reliability is good to assess medial-lateral patellar position, but inter-tester reliability was variable.  The variability is interesting to me and makes me wonder if we just aren’t standardizing how we look at patella mobility.

Another study by Herrington demonstrated that a group of 20 experienced therapists could reliably measure patellar position.  This tells me that a group of similar trained or skilled clinicians will show greater inter-tester reliability than a randomized selection of clinicians.  When I see that a test has good intra-tester and worse inter-tester reliability, I think one of two things:
The test is difficult to perform and/or is more accurate with more experience.

Reliability can be enhanced if we all use the same examination techniques. There may be subtle differences in techniques that may produce poor inter-tester reliability. This is what came to my mind when the Herrington study showed good inter-tester reliability with a group of experienced clinicians.

The Validity of Measuring Patella Mobility

In regard to validity of the measurements, the authors conclude that the criterion validity of this test is at worse moderate, based on limited evidence.  However, a couple of interesting studies were referenced.  A study by McEwan demonstrated that a lateral tilt of the patella greater than 5 degrees can be detected.  This was confirmed with MRI measurements.  The previously reported study by Herrington also reported that medial-lateral patellar position could accurately be measured as confirmed by MRI measurements.

A Simple Way to Measure Patella Mobility

It appears that clinical measurements of patellar positions can be both reliable and valid.  While intra-tester reliability, or your own ability to accurately repeat a test, appears to be more accurate, inter-tester reliability may be enhanced with a standardized examination technique.

Taking all this into consideration, I honestly do not try to “measure” patellar position.

I will assess the position but I do not try to place a label, such as millimeters or degrees, on the exact position.  If I want or need this information, I would much rather obtain this from a MRI.  I focus more on assessing the amount of hypomobility or hypermobility.

And there is a really simple way that we can do this that I think will great enhance our reliability.

To simplify this measurement, I try to just use a percentage of the patella that I feel can displace.  Here is how I do it:

  1. I break the patella down into 4 equal segments representing 25% of the width of the patella each.
  2. I visually try to establish where I believe the midline of the trochlea is located when I am measuring position.  If I am measuring displacement, I will visualize the edge of the lateral trochlea.
  3. I then measure the percentage of the patella that is positioned beyond the midline of the trochlea and then displace the patella and attempt to determine if 25%, 50%, 75%, or 100% of the patella can displace beyond the lateral edge of the trochlea, as in the image below:

Measuring the Position and Mobility of the Patella

I’ve learned over the years that knee experts, such as Dr. Frank Noyes, consider 50% displacement to be “normal.”  I use that as a frame of reference, but comparing side-to-side is probably even more important.

I feel that this provides me with plenty of information to compare to the other extremity and simplifies the process, which I hope would enhance intra- and inter-tester reliability.  If we all do it this way, I think we’ll be far more accurate.

What do you think? Is this too simple? How do you measure patellar mobility?

 

Return to Play Testing After ACL Reconstruction

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This week’s article is a guest post from Lenny Macrina.  Lenny discusses a really important topic right now regarding the safe return to sport after ACL reconstruction.  Are we returning people too fast? If you want to learn exactly how Lenny and I return people after ACL reconstruction be sure to check out our acclaimed online program on the Evaluation and Treatment of the Knee.

ACL reconstruction surgery continues to dominate the sports medicine and orthopaedic world. Research surrounding ACL surgery is abundant and I have written about it in previous posts on LennyMacrina.com and for Mike on his website. It’s an important topic because of the lack of general consensus on what’s the best way to assess return to play testing, never mind the relatively high failure rates.

For this post, I wanted to discuss the return to play testing after an ACL reconstruction to see what the literature says. I’m not going to lie, I don’t have a formal algorithm like some. I have people hop, skip and jump but don’t necessarily do a formal hop test.

I believe in slowly returning my athletes to their sport in a time that is safe. I carefully watch them move, advance their strength and power exercises and chat about how they feel about their knee.

With that, I wanted to do an extensive literature search to figure out what was the best way to truly test our athletes to determine their readiness.

Is there a best algorithm that will decrease retear rates? If so, why are we not using it for injury reduction programs…or are we?

Risks for ACL Reconstruction Failure

The risk of a second ACL injury in a young, active individual is high after a previous ACL reconstruction and return to sport.

Paterno and his group reported 23.5% of young, active patients suffered a second ACL injury in the first 12 months after RTS following ACLR.

Another study by Paterno and his colleagues showed 37.5% suffered a non-contact retear within 24 months after the initial reconstruction.

Surprisingly enough, this group also reported that 29.5% of young, active athletes who returned to cutting and pivoting sports after an ACL reconstruction suffered a second ACL injury 24 months after return to their sport.

A recent review by Wiggins et al showed that young, active athletes are at greater risk to suffer another ACL injury after ACL reconstruction and return to sport compared with uninjured adolescents.

With retear rates so high, there has to be a better strategy to get our athletes back to their sport safely.

ACL and Kinesiophobia

We know the mental component involving fear of movement/reinjury, or kinesiophobia, is often the last to come back for the athlete. A good majority of patients have some form of kinesiophobia after an ACL reconstruction and we need to be able to address that too. Numerous studies have shown this and it definitely needs to be understood and addressed as the program is progressed. Here’s another one for you to check out.

Those are just a couple of articles that discuss the self-reported fear that is involved in an athlete’s head. My pubmed search gave me 36 total articles that you may want to check out here.

There’s no denying the power of the mind when a return to play decision has to be made. I want them feeling as strong and confident as possible. It takes time and the days of trying to return someone back in 4-6 months seems to be a thing of the past. I did it.

Some self-reported outcome measurements that are commonly used are the TSK-11, known as the Tampa Scale for KInesiophobia. This is a shortened version of the original TSK-17 that was published previously.

shortened version of the original TSK-17

Another questionnaire that can be use is the ACL-RSI or the Return to Sport after Injury Scale. It is used to assess psychological impact that may be in the athlete’s head. The goal of the questionnaire is to the athlete’s emotion, confidence and self-risk appraisal.

There are many other tools out there that can gauge a patient’s knee function such as the IKDC, KOOS, VAS scale, Lysholm, Tegner, and the Cincinnati Knee Scoring scale. I just wanted to add those in as an informational thing but they don’t necessarily measure the psychological component ad readiness for return to play.

Slow and Steady ACL Rehabilitation

I’ve gotten high school seniors back to their sport quickly and bragged about it. Despite their isokinetic test being marginally ok, the docs would clear them because of other circumstances. It’s the last game of the season or it’s their senior year or they made the playoffs and the team ‘needs them.’

It seems as if the literature supports some form of formal testing but there is no clear answer, in my opinion.

The tests that many currently utilize in the clinic have just never felt right to me. I’m not sure we can simply do some hop tests or a step down test and have enough information to decide on whether an athlete is ready to return to their sport. Both tests are in the sagittal plane and don’t account for fatigue or other planes of movements such as the frontal plane (side to side) or transverse plane (rotational motions.)

Never mind that when we are comparing the involved leg to the uninvolved leg during functional testing to determine limb symmetry index (LSI), are we inherently flawed? Does the strength and proprioception of the uninvolved leg diminish months after the ACL reconstruction which makes our battery of tests invalid by inflating the LSI?

Rethinking the Way We Determine Return to Play After ACL Surgery

Delaware researchers seem to think that the LSI can overestimate knee function after an ACL surgery. They have shown that doing baseline functional tests soon after the ACL tear gives a better estimate of the body’s strength and functional output.

So if we’re using the uninvolved leg as the comparison leg and it has undergone strength and proprioceptive changes during the 6-12 months of rehab, are we flawed from the start and our LSI testing is invalid and over-estimates an athlete’s return to play?

Maybe that’s one reason why our retear rates are so high.

Physical Therapy Is Not Good at Advanced Stage Rehab

Never mind the pink elephant in the room…  many PT’s are poor at prescribing higher level exercises. We just don’t see people past 8-12 weeks after surgery because of insurance visit limitations. We don’t have experience or the access to these patients once they’re discharged from PT.

It’s at this point that the real strength, power, endurance and agility activities really take shape. Unfortunately, most patients are on their own or working with other professionals. It is key that we maintain our relationships with other fitness professionals so we can influence and guide the later-stage rehab process.

But we often don’t, sadly.

It’s a long process, longer than we think and longer than the patient wants it to be.

Should We Delay Return to Sport Longer Than 12 Months?

This article talks about how the rehab is multifactorial and can often take 1-2 years to feel comfortable enough.

Even renowned ACL researcher Tim Hewett, known for his injury reduction programs, has advocated for a 2 year return to sport in one of his latest papers.

Most are not functionally ready to return to their sport even though they are cleared by their surgeon. It seems as if time is the number one decision maker and not necessarily functional tests of strength power and endurance.

This paper showed that at 6 months, 2 patients (3.2%) passed all criteria. At 9 months, seven patients (11.3%) passed all RTS criteria. Patients improved in all RTS criteria over time except for the IKDC score. Twenty-nine patients (46.8%) did not pass the strength criterion at 60°/s at 9 months after ACL reconstruction.

While this research paper looked at younger athletes cleared for sports participation After an ACL Reconstruction.  Only 13.9% of the participants passed all of the criteria (IKDC, quadriceps and hamstring strength limb symmetry index (LSI), and single-leg hop test) 1 year after surgery

This study looked to assess the changes over time in patients tested at 6 months and 9 months after ACL reconstruction.  At 6 months, only 2 patients (3.2%) passed all criteria. At 9 months, 7 patients (11.3%) passed all criteria.

What if they had a previous ACL tear and then they subsequently tear the contralateral side? What does the PT use for an index?

A study by the Zwolski group that the use of LSI’s during strength and performance tests may not be an appropriate means of identifying residual deficits in female patients after bilateral ACL reconstruction. They also concluded that “a better indicator of strength performance in this population may need to include a comparison of strength performance values to the normative values of healthy controls.”

There seems to be a persistent issue with getting the quadriceps muscle to return in our athletes. Despite our efforts, there seems to be a neuromuscular component that requires time and persistence.

This study showed that in patients an average of 7.5 months out of surgery demonstrated nearly a 30% weakness. They said diminished motor neuron recruitment or decreased motor-unit–firing frequency was likely contributing to reduced isometric quadriceps strength and interlimb asymmetries.

Another study looked to compare adolescent athletes ages 15-20 years old with adults ages of 21-30 years old. At the 8-month follow-up, 29% of the patients, in both age groups, who had returned to sport had recovered their muscle function in all 5 tests of muscle function (unilateral vertical hop; unilateral hop for distance; and unilateral side hop, isometric quad at 60° and knee flexion at 30°.) At the 12-month follow-up, the results were 20% for the adolescents and 28% for the adult patients.

Again, a large strength deficit at 12 months post-surgery despite our objective testing.

Never mind that most of these studies lum everyone together and don’t account for graft differences. In my opinion, we need to consider graft type as another variable that could contribute to retear rates and return to sport testing. I talked about graft selection in this blog post.

How Do We Determine When Safe to Return to Sports?

That’s the million dollar question. There are a few common ways that we can determine when it is safe to return to sports after ACL reconstruction.

Isokinetic Testing

Isokinetic testing has been used for many years and seems to be valid and reliable. Although this recent systematic review in BJSM stated that  isokinetic strength measures have not been validated as useful predictors of successful RTS.

Oh great, now what?

Don’t forget, back in 1994 Kevin Wilk and his group looked to determine if a correlation exists between three commonly performed clinical tests: isokinetic isolated knee concentric muscular testing, the single-leg hop test, and the subjective knee score in anterior cruciate ligament reconstructed knees. They noted a positive correlation was noted between isokinetic knee extension peak torque (180, 300 degrees/sec) and subjective knee scores, and the three hop tests (p < 0.001).

The problem lies with many clinics having limited access or just don’t use them anymore.

Because of that, we’ve had to adjust our thinking and use ground based testing such as hop tests, isometric strength testing and agility tests.

The research says that “athletes who did not meet the discharge criteria before returning to professional sport had a 4x greater risk of sustaining an ACL graft rupture compared with those who met all 6 RTS criteria (isokinetic strength testing at 60°, 180° and 300°/s, a running t-test, single hop, triple hop and triple crossover hop tests.) In addition, hamstring to quadriceps strength ratio deficits were associated with an increased risk of an ACL graft rupture.

This study says that the single hop for distance and ACL-RSI were found to be the strongest predictive parameters, assessing both the objective functional and the subjective psychological aspects of returning to sport. Both tests may help to identify patients at risk of not returning to pre-injury sport.

Hand-Held Isometric Strength Testing

This is another test that is commonly used in return to sport testing after an ACL. I think it could be used but it gives limited information and can be painful if not done correctly. The painful response has been shown to statistically influence outcomes and needs to be modified to prevent alterations in true quadriceps force generation.

Also, the measurements using a hand held dynamometer are often lower than what can be obtained with an isokinetic device, as seen in this study.

I know many use hand-held dynamometry but I just can’t see its value as a return to sport test that is valid.

There are just too many questions about where to put the device to minimize pain while kicking. Also, at what angle do we place the knee to best isolate the quadriceps? Ninety degrees or 60 degrees of flexion? Research seems to look at both methods.

Plus, does a concentric, isometric contraction REALLY give us the information that we truly need to make an informed decision or have we sought a cheaper alternative to isokinetics and embraced it. We PT’s are suckers for the easiest way to diagnose, treat and test and often miss the big picture.

Research can guide us but common sense and experience must play some role as well.

Hop Tests to Determine Return to Play

Hope tests are often utilized by rehabilitation specialists to determine an athlete’s ability to generate and dissipate a force when compared to their contralateral knee. As far as I can see, Noyes was one of the 1st to talk about hop tests in the literature in 1991.

Four common tests are utilized and reported in the literature. They include single leg hop for distance, triple hop for distance, crossover hop for distance and 6-meter time hop. The general rule is to obtain an LSI ≥ 90% compared to the reference limb.

Hop Tests

As usual, both limbs are tested and the uninvolved limb is used as the reference, which we mentioned previously as an inherent potential flaw (the Delaware study.)

Using these tests can help the rehab specialist reduce ACL re-tears as noted in this study from BJSM in 2016. They showed reinjury rates were “significantly reduced by 51% for each month RTS was delayed until 9 months after surgery, after which no further risk reduction was observed.”

Furthermore, 38.2% of those who failed RTS criteria involving hop tests and quad strength symmetry within 10% suffered re-injuries versus 5.6% of those who passed all of the testing criteria.

Closing Thoughts on ACL Return to Sport Testing

My research has confounded my thoughts even more and added to the questions. It seems as if there is no clear way to determine readiness to return to sport after an ACL. Our testing seems somewhat flawed and despite our efforts, ACL retear rates are too high.

To simply say it comes down to strength is not enough. We’re so focused on quadriceps strength that we’re missing the big picture. Of course the quadriceps are highly important, bt don’t forget about hamstring:quadriceps ratios, gluteus strength, force attenuation, and fatigue-state rehab.

Never mind there’s the mental component and the ability to attenuate forces in game situations. These are things we cannot truly test.

We’re missing something but it does seem that the time-based scenario may be an option to consider, meaning they need to stay out of their sport for at least 9 months, and ideally 12-24 months, or as long as they are continually doing their progressive strength training.

I think therein lies the answer. As physical therapists, we don’t do a very good job at advanced strength training and periodization. We can learn a lot from our fellow strength coaches. Plus the fact that the athlete is all too eager to return to their sport without fully understanding the consequences.

Despite all of our testing, we continue to show poor outcomes even 12+ months after reconstruction. I can’t blame the tests, right? It’s the preparation for the tests that seems to be lacking.

What do you do to test your athletes when they’re considering a return to their sport?

Learn How We Evaluate and Treat the Knee

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For those interested in learning more about how Lenny and I evaluate and treat the knee, we have an amazingly comprehensive course that covers everything you need to know to master the knee.  Our detailed examination process, all our treatment progressions, and detailed information on nonoperative and postoperative treatment of ACL, patellofemoral, meniscus, articular cartilage, osteoarthritis injuries, and so much more.

4 Mistakes People Make When Rehabilitating Hamstring Strains

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When it comes to hamstring strains, two things are certain:

  1. They are very common in athletes, with research showing almost 30% of all lower extremity injuries in sports are hamstring strains.
  2. The recurrence rate is high, with research showing up to a 30% recurrence rate for hamstring injuries.

Call me crazy but I feel like the recurrence rate is just way too high, showing that we either are rushing people back too soon, don’t have an adequate return to sport criteria, or simply are not rehabilitating these hamstring strains very well.

It’s likely a combination of the three. We can do better.

4 Mistakes People Make When Rehabilitating Hamstring Strains

In my experience, people often make 4 common mistakes with hamstring strain rehabilitation. By focusing on these 4 key areas, I think we can do a better job returning athletes to their sport following hamstring strains, and keep them out on the field without reinjuring their hamstrings.

Loading the Hamstring Too Early

The first mistake I often see is simple. People often load the hamstring tissue too early.

I think it’s obvious that contracting a strained hamstring causes pain, so this is often avoided, but for some reason people tend to want to stretch through this pain and discomfort, thinking that if they get looser it will feel better.

I don’t think this is true, and overstretching too early is just going to delay healing. In fact research has shown that too much stretching can actually delay the return to sport.

This can occur in the rehabilitation setting, but also from the athlete themselves as the constantly want to stretch or “test” the area throughout the day.

One of the easiest things you can do acutely after a hamstring strain is to avoid stretching. Don’t get me wrong. I want to start some gentle range of motion in the acute phase, but I don’t want to stretch the tissue that was essentially just damaged by an overstretch type of injury.

Trust me, take a step back in the acute phase and avoid stretching and you are putting the tissue in a position to succeed in the future phases on rehabilitation when we need to start applying more load.

Not Performing Eccentric Exercises

It has been theorized that hamstring strains are so common due to the large eccentric contractions observed during the swing phase of running as the hip flexes and the knee extends.

This seems to make sense.

So it also makes sense that hamstring strain rehabilitation and even prevention programs that incorporate eccentric hamstring exercises tend to have better results.

After a hamstring strain, it has been shown that eccentric hamstring strength is impaired.

The common theory is that there is a change in the force-length relationship of the hamstring after an injury, resulting in peak force at a shorter length. But, eccentric training shift this relationship and allow peak force at a longer length.

This makes is important to include eccentric exercises for the hamstring during rehabilitation. I also recommend you include eccentrics with exercises at various degrees of hip flexion, for example the Nordic hamstring exercise at 0 degrees, and a single leg RDL, which includes hip flexion.

Not Performing Dynamic Hamstring Exercises

While it’s important to include eccentric exercises, I’m actually surprised at how little I read about people recommending dynamic exercises.

It’s one thing to perform a slow eccentric contraction, and another to perform a dynamic and explosive contraction.

I often use lower body plyometrics for this, as it allows both a rapid eccentric contraction, followed by an explosive concentric contraction. That’s what happens in sports.

Returning to Sports Too Early

Several studies have been published showing that many athletes return to sport too early, showing signs of hamstring weakness and imbalances.

Part of the problem is that there is no validated criteria to determine return to sport. But, we are getting there.

It’s probably best to understand the factors that are associated with prolonged hamstring injuries, you can read a nice review of those in AJSM.

But we also may have a new clinical test that can be performed. The Askling test involves have the person rapidly perform an active straight leg raise to assess their ability to perform and pain.

askling test for hamstring

It has been shown that the recurrence rate of hamstring strains that passed the Askling test was less than 4%, much lower than the normal rate.

How to Diagnose and Treat Hamstring Strains

For those that want to learn more about how I rehabilitation hamstring strains, including the postoperative rehabilitation follow hamstring repairs, I have an Inner Circle presentation on the Diagnosis and Treatment of Hamstring Strains that overviews my approach to these injuries. Click below to learn more:

How to Diagnose and Treat Hamstring Strains

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The latest Inner Circle webinar recording on How to Diagnose and Treat Hamstring Strains is now available.

How to Diagnose and Treat Hamstring Strains

This month’s Inner Circle webinar is on How to Diagnose and Treat Hamstring Strains. In this presentation, I’m going to overview a simple 3 phase approach to rehabilitating hamstring strains. Hamstring strains can be tough, and have a really high recurrence rate. But luckily there are things you can do to assure we are helping the tissue remodel and accept load again.

This webinar will cover:

  • The anatomy and injury mechanics behind hamstring strains
  • The best way to diagnose and grade hamstring strains
  • A 3 phase rehabilitation progression to get back on the field
  • What to focus on to reduce recurrent strains in the future
  • The postoperative rehabilitation following hamstrings repair

To access this webinar:

What is the Best Graft Choice for ACL Reconstruction?

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Today’s article is from my co-owner of Champion PT and Performance and co-author of OnlineKneeSeminar.com, Lenny Macrina.  Lenny does a great job discussing and comparing the different options when it comes to graft choice for ACL reconstruction.

Tearing an ACL can be a devastating experience.  Fortunately you are not alone as more than 250,000 people will tear their ACL in the United States and over 80% of people will have that tear reconstructed.

When the injury does occur, the person has some serious decisions to make including which graft to choose for the reconstruction. Often times, the person will leave that decision up to the orthopedic surgeon and blindly go with that decision.

All too often, the graft choice for that person may not be the best option for their age, goals and for their lifestyle, amongst many other things.  Consideration for the current research should play a big role in this decision-making process on which graft to use for ACL reconstruction.

So, what graft choices are out there and why may one be better than another one?

Well, as I normally say ‘it often depends,’ but I usually coach my clients and start with the gold standard, consider the pros and cons, then move onto the next best option.

ACL Reconstruction Graft Choices

What are the options and why choose one over the other?  First, I want to clarify the difference between “autograft” and “allograft.”  Autograft means using your own tissue.  Allograft means using tissue from a cadaver.

The most common choices available are:

  • Patellar tendon autograft
  • Hamstring autograft
  • Quadriceps tendon autograft
  • Patella tendon allograft

Let’s look at some of the research behind each ACL graft choice.

Patella Tendon Autograft

To me, the gold standard of ACL reconstruction is the patella tendon autograft and should be considered for most people in their teens, 20’s and for many in their 30’s or 40’s.

It is believed that the bone-patella tendon-bone graft has a stronger fixation because of the bone plugs that can incorporate into the femoral and tibial tunnels by 6-8 weeks after surgery.

Better graft fixation may prevent stretching or excessive laxity that is often seen with hamstring autografts and allografts. A strong and stable graft is key when considering the long term stability of the knee joint, as seen in this video showing the harvesting of the graft and the reconstruction.

Numerous studies have shown that re-tear rates are also significantly lower in patients undergoing a reconstruction with a patella tendon versus a hamstring tendon autograft.

A Scandinavian study looking at nearly 46,000 reconstructions showed this as well as a Norwegian study looking at greater than 12,000 reconstructions.  Furthermore a Danish study of nearly 14,000 reconstructions showed similar results.

Here in the US, a similar trend has been identified when looking at revision rates amongst the different graft choices. In this study out of over 21,000 reconstructions in California, patients under 21 years old with hamstring autografts had a 1.61 times higher risk of revision than did patients with patella tendon autografts. In patients less than 40 years old, those with allografts had a higher risk of revision than those with patellar tendon autografts.

A couple of disadvantages that are often reported after the surgery are an increase in general knee pain because of the soft tissue and bony dissection and anterior knee pain. This anterior knee pain may be more of a long term issue for some, especially while trying to kneel, because of the graft harvesting and scar that remains. To me, this is a small inconvenience but I always let my clients know of the potential long term kneeling limits. Usually not a big deal for most but you never know.

Some often say that it is more difficult to get a patient’s range of motion back, especially their hyperextension, if a patella tendon graft was used. I, personally have not seen this and have addressed this in a past article on 3 Ways to Avoid Loss of Motion After ACL Reconstruction.

I’ve actually had more difficult times getting hyperextension back in my hamstring autografts for some reason. They often feel that residual medial knee pain where the tendon was harvested and are reluctant to allow me to stretch them out into hyperextension.

Regardless, while anterior knee pain and range of motion restrictions are often cited as concerns, in my experience I feel these can be overcome with good postoperative rehabilitation.

Hamstring Tendon Autograft

The hamstring tendon autograft is another graft option for someone about to undergo an ACL reconstruction, as you can see in this video by Dr. Khalfayan:

I think it is too widely used currently and we need to further assess the outcomes and high risk of re-tear rate studies that I just presented.

Yeah, it may hurt less, and I stress MAY, but in my experience it is a graft that often presents a pretty big pain challenge. I’ve seen people in very comparable pain to a patella tendon graft because of the soft tissue dissection involved in the harvesting.

Think about a tendon shaver being poked under your skin high enough to clip the tendon from the muscle belly. No wonder hamstring grafts have a pretty significant bruising effect on the posterior aspect of their knees.

Ok, what about the famous: “But you can come back faster and progress rehab faster?”

I often hear this from patients who have done some research or have spoken to other health care practitioners but I completely disagree and actually progress people SLOWER with a hamstring autograft.

And here’s why…

The healing capacity for a hamstring autograft is believe to be inferior to the patella tendon graft.  Remember the Ekdahl study from 2008 but there are others too.

I know many are in sheep, goats and dogs but that’s all we have to guide us right now. Until humans will volunteer their knees periodically through a study to get histological samples, then we have to rely on animal studies to guide our thoughts and progressions.

And don’t forget there is an increased risk of infection with a hamstring graft compared to a patella tendon autograft or allograft.

But good news, many say the hamstring will regenerate after being taken out although the strength deficits into knee flexion persist.

Because of this, I often progress my patients that have ACL reconstruction using a hamstring autograft much slower than those with patellar tendon autografts.

A slower healing potential that may lead to graft stretching and eventual failure, never mind the potential strength deficits that may persist and affect jumping/landing biomechanics due to the use of the hamstring.

Remember, the hamstrings line of pull will help limit anterior translation of the tibia and dynamically stabilize during running, jumping and cutting tasks. If we take 1-2 of those tendons out, how will that affect the athlete short term and long term as they return to their function/sport.

Maybe that’ another reason why re-tear rates are statistically higher in ACL’s reconstructed with a hamstring graft?

I definitely go slower with my female clients, as well, who are much more likely to tear their ACL’s, in general.

Remember, numerous studies like this, this, this, and this have shown females to land in a quadriceps dominant and valgus position, which may predispose them ACL rupture, amongst many other reasons.

So, why would we even consider a hamstring graft in an active female population and take away one for their main stabilizers. It’s almost like we’re promoting the quadriceps dominant position by “robbing Peter to pay Paul.”

For this reason, I almost always tell my female clients to highly consider a patella tendon autograft. Furthermore, I very rarely recommend a hamstring graft for most of my patients that ask.

I just feel like the risk of re-tear outweighs the POTENTIAL for increased anterior knee pain after surgery. They tend to agree, quite often.

Quadriceps Tendon Autograft

Another autologous graft option, which I feel is underutilized, is harvesting a quadriceps tendon autograft to reconstruct the ACL. Honestly, the more I researched this graft option, the more I consider this a truly viable choice.

This video give a great overview of graft harvesting for the quadriceps tendon:

Numerous studies have shown very good outcome compared to hamstring and patellar tendon autografts. I could make a pretty good sized list but have picked just a few to make my point. Like this one, this one,  or this one.

Because of the size comparison and increased collagen present within the graft, the quadriceps tendon graft is definitely a graft with comparable strength qualities compared to the previous grafts mentioned.

This table, taken from the lectures at from my online course with Mike Reinold at OnlineKneeSeminar.com, summarized strength and strength to failure of the various graft choices.

What is the Best Graft Choice for ACL Reconstruction

Biomechanically, the cross-sectional area of the quadriceps tendon was nearly twice that of the patellar tendon. Ultimate load to failure and stiffness were also significantly higher for the quadriceps tendon graft.

Well, maybe we consider a hamstring graft if the primary revision failed and we need a new graft option?

I still say maybe consider an ipsilateral quadriceps tendon before thinking about a hamstring tendon. This study showed revision ACL reconstruction using the quadriceps tendon graft showed clinical outcomes similar to those of the contralateral hamstrings graft in terms of knee stability and function.

But we said pain was less in hamstring grafts, right?

We’d rather have less pain so I can progress ROM and function quicker, no?

Well, maybe not, as this study showed comparing quadriceps to hamstring autografts. Supplementary analgesic drug was 38% higher in the hamstring group compared with the quadriceps tendon group.

Guess the hamstring option isn’t so painless!

Allograft Tissue

What about the ‘other’ graft choice that seems to be utilized a decent amount in the sports medicine and orthopedic world, the allograft.

Allograft tissue, or cadaver grafts, have recently become very popular in the United States for some reason, despite the numerous studies like this or this that show higher revision rates and graft stretching never mind the often under-reported cases of allografts being degraded by the body’s immune response.

I will say there is some research out there that is showing similar outcomes in allografts not chemically processed or irradiated when compared to autografts.  But we are still learning.

This study looked at outcomes and revision rate after bone-patellar tendon-bone allograft versus autograft ACL reconstruction in patients aged 18 years or younger with closed physes. They determined there was no significant differences in function, activity, or satisfaction were found between allograft and autograft reconstructions BUT the allograft group had a failure rate 15 times greater than that in the autograft group, with all failures occurring within the first year after reconstruction.

I’ve spoken to surgeons who have  reported almost no remnants of the previous allograft at the time of the revision surgery. It’s like the patient’s body completely rejected the graft.

That’s just a risk I almost never want to take.

I’d maybe consider an allograft for an older but active patient, say in their 50’s or 60’s but very rarely for an active person. I’d definitely not recommend an allograft to an athlete in their teens and 20’s although I have personally seen many kids present to me post- primary or revision surgery with an allograft reconstruction.

When I asked them why they chose it, they most often say: “it was recommended by the physician because I may be able to return to sports sooner and less pain.”

I could not disagree anymore and usually have to give them my dissertation on graft healing and the potential for graft rejection (as I mentioned previously).

Again, we think it takes several months longer for allograft tissue to incorporate itself compared to autograft tissue. There are very few reasons why someone should return their sport any quicker when the tissue is not fully incorporated, so why even consider it?

I very RARELY recommend an allograft for an ACL reconstruction. I frequently have to talk clients out of this option because the 1st thing they see or hear is there’s less pain. When they hear the whole story, they quickly realize an autograft seems to be the right choice.

Choosing the Right ACL Graft

Which autograft will depend on many factors but it seems like a patella tendon or quadriceps tendon may be the grafts of choice.

If you tore your ACL and are considering ACL reconstruction surgery, consider these factors when deciding which graft may be the most appropriate for you.

Learn How We Evaluate and Treat the Knee

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For those interested in learning more about how Lenny and I evaluate and treat the knee, we have an amazingly comprehensive course that covers everything you need to know to master the knee.  Our detailed examination process, all our treatment progressions, and detailed information on nonoperative and postoperative treatment of ACL, patellofemoral, meniscus, articular cartilage, osteoarthritis injuries, and so much more.