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Expert Advice on Youth ACL Injuries

youth acl injuriesFor this week’s post, I wanted to share what I thought was a great video from the American Orthopedic Society for Sports Medicine (AOSSM) on youth ACL injuries.

In this video, noted orthopedic surgeons Chris Harner, Lyle Micheli, James Andrews, and Peter Indelicato share their advice on several topics regarding youth ACL injuries, return to play, female ACL injuries, and preventative programs.

Videos like this are important to education the parents and coaches on the realities of issues like youth ACL injuries.

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Do ACL Hamstring Grafts Fail More than Patellar Tendon Grafts?

This month’s issue of the American Journal of Sports Medicine included two studies comparing the revision rates of ACL reconstruction between hamstring grafts and patellar tendon grafts of over 25,000 people.  The overall number of people studied between the two groups was really compelling to me as a sample size this big is certainly worth discussing.

In recent years the graft choice for ACL reconstruction has been slowly shifting towards favoring hamstring grafts rather than patellar tendon grafts.  Recent reports have noted 84% of ACL reconstructions in Denmark and Sweden use hamstring grafts, 60% in Norway, and now are even becoming more popular in the US with 44% of ACL reconstructions using a hamstring graft compared to 42% using a patellar tendon graft.

Many research papers have been published showing that both grafts result in very good stability of the knee with excellent subjective outcome scores.  The major complaint of patellar tendon grafts is the increased risk of issues after surgery, such as patellofemoral pain and loss of motion.  Despite the reports of good stability and subjective outcomes, revision surgery is probably a more important factor to consider.

 

Do ACL Hamstring Grafts Fail More than Patellar Tendon Grafts?

The first study reviewed the nationwide Danish Knee Ligament Reconstruction Registry, which included 13,647 people undergoing ACL reconstruction between 2005 and 2011.

The revision rates for hamstring tendon grafts were 0.65% at 1 year after surgery, and 4.45% at 5 years after surgery.  The revision rates for patellar tendon grafts were 0.16% at 1 year after surgery, and 3.03% at 5 years after surgery.

Essentially, hamstring grafts had a 4x greater risk of revision in year one and 1.5x at 5 years following ACL reconstruction.

ACL reconstruction revision rates

The second study reviewed the nationwide Norwegian Cruciate Ligament Registry, which included 12,643 people undergoing ACL reconstruction between 2004 and 2012.

The revision rates for hamstring tendon grafts were 5.1% at 5 years after surgery, and 2.1% for patellar tendon grafts.  This study also looked at different age groups and found this increased rate to be consistent across all age group.s  However, the younger group (age 15-19) had a 9.5 revision rate at 5 years using the hamstring graft in comparison to 3.5% using a patellar tendon graft.

Together, there was a 2x greater risk of revision overall when using the hamstring graft, but closer to 3x greater risk for younger people.

ACL hamstring patellar tendon graft

 

Both Grafts are Great Options for ACL Reconstruction

When we really assess the numbers, it is clear that both graft options are great choices with low revision rates.  Even though we are comparing the two, realistically the revision rates after ACL reconstruction are low for both hamstring grafts and patellar tendon grafts.  There are many factors that go into deciding which graft to use.  Also realize this does not apply to skeletally immature patients.  This revision information is just a piece of the puzzle.

The patellar tendon graft has less failure rate and has been reported to heal faster in animal models due to the bone-to-tendon interface.  While this is true there are also reports of increased anterior knee pain and loss of motion.  I have discussed this in the past, but I really do believe that many of the issues with patellar tendon grafts after surgery are minimized or eliminated with proper physical therapy (in addition to excellent patient compliance).  This is especially true if these factors are the primary emphasis of the early phases of ACL rehabilitation.

SEE ALSO: 6 Keys to the Early Phases of Rehabilitation Following ACL Reconstruction Surgery

That all being said, hamstring grafts have also been shown to result in less strength of the hamstrings after surgery.  Considering the role of the hamstring to assist the ACL in control anterior tibial translation, this has to be considered when reviewing the higher ACL reconstruction revision rate when using hamstring grafts.  Perhaps it really has nothing to do with the graft itself and more to do with the hamstring strength.

Regardless, the revision rate following ACL reconstruction is higher when using a hamstring graft than when using a patellar tendon graft.

 

 

6 Keys to the Early Phases of Rehabilitation Following ACL Reconstruction Surgery

Rehabilitation following ACL reconstruction surgery has evolved significantly over the last 25 years.  We have progressed from casting the knee to allowing immediate motion and weight bearing in just a short amount of time.  As our understanding of rehabilitation concepts continue to evolve, our focus has shifted towards functional exercise and rehabilitation progressions, which is integral to maximize results following ACL reconstruction surgery.

We are now seeing professional athletes absolutely dominate their postoperative rehabilitation.  Adrian Peterson is now going to be the poster-boy for return to sports after ACL surgery after tearing up the league and winning NFL MVP just months after having ACL reconstruction surgery.  While, AP is definitely the exception, not the rule, the postoperative rehabilitation is a huge factor in determining how well people recover from surgery.

While everyone wants to talk about advanced exercises and return to sport, it is probably infinitely more important to assure that the early phases of rehabilitation go well to avoid complications and allow more advanced drills down the road.  If the early phases of ACL rehab go poorly, you will surely be behind for the duration of your rehab.

On that note, I wanted to discuss the 6 keys to the early phases of rehabilitation following ACL reconstruction surgery.  Master these basics and the advanced phases get easy.

 

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Diminish Pain and Inflammation

early rehabilitation following acl reconstruction surgeryThe first key to ACL Rehabilitation is simple, diminish the pain and inflammation associated with the surgery.  While this is a no-brainer, it is worth reviewing why this is so important.  Really, the following list of keys to ACL rehabilitation are all going to be difficult to achieve without addressing the pain and swelling.  Here are just handful of important things to consider:

  • Pain and swelling has been shown in numerous studies to essentially shut down your muscles around your knee, specifically your quadriceps.  Even a small amount of fluid in the joint has been shown to decrease your ability to contract your quad.
  • Without a quad, it is hard to function, and you tend to walk around with a bent and stiff knee.
  • Pain and swelling will limit your range of motion progression.

So, as simple as this concept may be, diminishing pain and inflammation should be an area of focus initially after surgery.  Compression wraps, ice, intermittent compression machines, elevation, ankle pumps, electrical stimulation, and not pushing through too much activity can all help.

My biggest advice to patients after surgery is that you can’t ice too much.

 

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Restore Full Knee Extension Motion

Loss of knee extensionRestoring full knee extension range of motion could be the #1 key to rehabilitation following ACL reconstruction surgery, however I chose to list it second here because addressing pain and swelling has implications for everything discussed in this article.  Really, though, my focus is almost always directed towards restoring full knee extension as soon as possible.  One of the more common complications following ACL surgery is loss of motion, with loss of extension being more troublesome than flexion.

When pain and swelling is present, it is just more comfortable to hold your knee in a slightly bent position.  Keep it this way too long and you run the risk of developing scar tissue, or arthrofibrosis.  Restoring knee extension immediately after surgery is so important, because once it gets tight, it’s often hard to get your motion back.  I’d much rather focus on this initially and slowly restore motion than get too tight and then have to aggressively attempt to improve motion.  That is never preferred.

Loss of full knee extension does not allow the knee to function properly, even if just a small loss of motion.  Plus, studies have shown loss of motion to be one of the most important factors associated with the development of arthritis after ACL surgery.

Luckily, with proper rehabilitation, loss of motion can be avoided.

In addition to my range of motion, soft tissue mobilization, and manual therapy techniques, I always instruct patients to perform a lot of range of motion and stretching exercises at home, essentially once an hour.  I like to show them hamstring stretches and calf towel stretches.  I don’t perform these stretches to really enhance hamstring and calf flexibility.  I perform them and instruct the patient to also work on knee extension at the same time.  So the focus is essentially knee extension.

Knee Extension Stretch ACL Reconstruction

Towel Knee Extension Stretch ACL Surgery

If loss of motion starts to become a problem, I don’t hesitate to start to introduce low-load long-duration stretching.  My goal is full knee extension by 1 week after surgery.  Biomechanical studies have shown that the stress of the ACL graft when stretching into extension is below the forces seen during common functional activities, so there is no need to avoid this motion.

This is such an important concept, that you may want to review my past article dedicated to restoring knee extension range of motion.

 

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Gradually Progress Knee Flexion Motion

Knee Flexion Range of Motion ACL RehabilitationAlthough loss of knee flexion doesn’t tend to be as common as knee extension, it does happen and you don’t want to neglect working on flexion.  There is often a see saw between flexion and extension.  The more you work on one, the more you tend to get stiff in the other direction.  This is reduced by working on frequent bouts of gentle but progressive range of motion.

I also like to empower the patient to also work on restoring knee flexion, both by stretching as well as through functional motions like mini-squats and eventually lunges.  When the patient can control their range of motion progression, their perceived threat is reduced and motion often comes back easier.

Knee flexion is restored more gradually, with about 90 degrees achieved at 1 week and full knee flexion gradually advanced and achieved by week 4-6.

 

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Maintain Patellar Mobility

Patellar Mobilization ACL RehabSometimes one of the reasons that range of motion is reduced is because patellar mobility is lost.  Full patella mobility is required for knee flexion and extension.  As the knee is painful, swollen, and difficult to move, scar tissue can form and limit patella mobility.  This is especially true if a patellar tendon graft is used for the ACL reconstruction surgery.  If patellar mobility is neglected, the chances of loosing range of motion goes up significantly.

Soft tissue mobilization around the knee and patellar mobilization is performed immediately after surgery.  I also like to instruct patients on how to do this themselves and add it to their homework.

 

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Restore Volitional Quad Control

NMES quad ACLAs previously mentioned, there is a reflexive inhibition of muscle control around the knee after surgery due to the pain, inflammation, and swelling.  In addition to address these factors, there are techniques that can be performed to help restore volitional control of the quadriceps muscle.

Lynn Snyder-Mackler, at the University of Delaware, has produced dozens of articles on the use of neuromuscular electrical stimulation (NMES) on the quad follow ACL surgery.  Essentially, NMES helps restore quad strength and function faster that just exercises without NMES.

Naturally NMES becomes an important component of the early phases of ACL rehabilitation.  I will superimpose most early quad exercises that we perform with NMES.  This includes quad sets, straight leg raises, and knee extension exercises.

An added benefit of all these quadriceps contractions is that this also helps restore knee extension range of motion.

 

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Restore Independent Ambulation

Retrowalking ACL Rehabilitation

Now that we have addressed the pain and swelling, started to restore motion and patellar mobility, and can now turn on the quads, we put it all together to work on being able to walk without limitations or a limp.  If any of the previously mentioned areas of focus have not been addressed, independent ambulation is often going to be difficult, or at least impaired.

I usually have people weight bearing as tolerated around week 1, unless other structures were damaged or need to be protected.  We may continue to use the crutches for up to two weeks, however, I still want them to be able to walk and just use the crutches as assistance, rather than, well, a crutch…

I have found weight bearing exercises like weight shifts that focus on transferring your weight and locking out your knee can be helpful initially.  I also tend to use cone walking drills to help groove the pattern of shifting weight and transitioning to single leg stance.  I have also found backward walking while stepping over a cone to be helpful to rock the body back over the foot and assist with achieving knee extension.

 

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More Information

Those are my 6 keys to the early phases of rehabilitation following ACL reconstruction surgery.  I try to focus on each one of those keys during each session I have with a patient.  These 6 keys are so important, that I would rather increase my visits early in the rehab process to assure that these are all addressed, then try to conserve visits (per our insurance limitations).

SEE ALSO: Download a free copy of my ACL Rehabilitation Protocol

Really, this is just the tip of the iceberg.  If you haven’t seen it yet, my coauthor Kevin Wilk has contributed 4 different webinars of  4 hours of content detailing exactly how he rehabs people following ACL reconstruction.  Kevin is no doubt one of the best there is at ACL rehab.  He and I have probably rehabbed over 1000 ACL reconstructions in our careers, including many professional athletes.  If you want to learn from the best, take a look at Kevin Wilk’s ACL Rehabilitation webinar series at RehabWebinars.com.

Wilk ACL Rehabilitation

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Show and Go, ACL Rehabilitation, and Exercises to Target Specific Hamstring Muscles

This week’s Stuff You Should Read comes from Eric Cressey and Sports Medicine Research.  Also, who likes my new logo at the top of the page?  I was finding just my name in plain text was boring.  Yes, that is my hand writing, and yes, I write in all capitals.  I don’t know why, I’ve been doing that since elementary school…

 

Inner Circle Update

My webinar from last week has been posted!  We spent an hour talking about how to use science and evidence to enhance your exercise selection.  This is a topic I love as I really feel like this concept can really set you apart.  To view the webinar, make sure you are logged in and then go to the Using Science to Enhance Exercise webinar page.

My next webinar will discuss my top 5 tweaks to really enhance hip exercises.  I’ll announce the date sometime later in the month.  Join now for only 5 bucks and get access to all future and past webinars.

 

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RehabWebinars.com Update

This week’s webinar is an awesome contribution from Dr. Stephen O’Brien on his treatment algorithm and approach to injuries to the biceps labrum complex.  The biceps as a contributor to shoulder pain is a HOT topic right now!  You can’t go to a meeting without this topic coming up.  There is no better expert than Dr. O’Brien, who you may recognize from the SLAP O’Brien test that he popularized.  It is expert talks like this that makes RehabWebinars.com so outstanding and filled with resources you just can’t get anywhere else.

There were also a bunch of new ones added last week if you missed it, including talks on Peripheral Neuropathy, Surgical Options for Arthritis in the Young Patient, and Part 2 of Kevin Wilk’s webinar series on Current Concepts in ACL Rehabilitation.

 

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Cressey’s Show and Go

My friend Eric Cressey is putting his popular Show and Go program on sale for the week.  It’s on sale for $50 off until the end of the day Sunday.

Click here to get it now before the sale ends

I used the Show and Go program as my offseason workout last year and can say that it is a great program that you can use for many different types of people.  As a clinician, I see this as a way to learn the what, why, when, and where of strength and conditioning programming from an expert in the field.  Here is a webinar Eric did last year that discusses how he builds strength and conditioning programs for people with muscle imbalances, a topic that fits very well with us clinicians:

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Click here to get it now before the sale ends

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Exercises to Target Specific Hamstring Muscles

Sports Medicine Research posted a summary of a recent article that evaluated several different exercises and their ability to target specific muscles of the hamstring group.  This is important information when rehabilitating a specific hamstring injury, as well as when designing comprehensive programs.. We should essentially be sure to include exercises that target all aspects of the hamstrings.

 

 

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Biomechanics of TRX Squat Variations

The TRX Suspension System is a pretty cool piece of exercise equipment that has some obvious (i.e. rows!) and not so obvious uses.  The strength community has shown us tons of great uses of the TRX, but I also personally use the TRX many ways within my rehabilitation programs.

Here is a video of some simple variations to the squat that can be performed by using the TRX.  I’ll explain more about why I use these TRX squat variations below, but take a look at the clip first:

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Muscle Activity During Squats

Biomechanical studies have shown that altering your center of gravity impacts the resultant muscle activity ratios between the quadriceps and hamstrings.  This was demonstrated well in the classic 1996 study by Wilk, Escamilla, and Fleisig publish in AJSM.  The authors compared squatting and leg press and found that the plane of orientation of the body produced a significant effect on muscle activity.

During the upright squat, when the center of gravity is fairly neutral, the quadriceps and hamstring muscle groups produced a relative amount of co-conraction during the concentric portion of the exercise:

EMG Squat

 

However, when the leg press was performed and the center of gravity was positioned posteriorly, the contribution of hamstrings to the activity was significantly less:

EMG Leg Press

 

Basically when performing an exercise where you center of gravity is posterior, such as a leg press or wall squat, you will increase quadriceps activity and decrease hamstring activity.  Conversely, if you lean forward during a squatting motion, you will increase the hamstrings contribution.  Lastly, a neutral squat with a neutral center of gravity will produce co-contraction of the two muscles.

 

TRX Squat Variations

These biomechanical findings can be used to alter the ratio of quadriceps to hamstrings during the squat as needed.  Clinically, there are times during the rehabilitation process where this may be beneficial.

For example, a patient recovering from ACL reconstruction surgery may benefit from performing neutral squats to facilitate co-contraction and stability of the knee. A patient with a PCL injury may want to perform squats from to neutral to posterior to their center of gravity to reduce hamstring contribution and the potential for posterior shear forces.  If you want to facilitate posterior chain involvement during the squat and emphasize hip extension, you may want to lean forward and work on this motor control pattern.

As you can see there are a lot of potential clinical implications.

Using the TRX to perform these squats is very helpful, expecially during the early phases of rehabilitation.  The TRX suspension system can take some weight off the squat, enhance balance so the patient can shift their center of gravity more anterior or posterior, and serves as what I like to call “training wheels” to help perform a squat correctly when movement dysfunction exists.  Just a small reduction in body weight can enhance motor control and help movement quality during the squat.  As the person’s motor control improves, they can ween off the TRX “training wheels.”

What do you think?  How have you used the TRX during rehab?  These are just a few examples of how using the TRX suspension system can help us tweak an exercise like the squat.  Understanding the biomechanics of the squat and what happens on the inside during these TRX squat variations will help us build better programs for our patients and clients.

 

 

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Assessing and Treating Loss of Knee Extension Range of Motion

Assessing and treating loss of knee extension range of motion is an important component of rehabilitation following any knee surgery.  We recently discussed how loss of knee extension range of motion may be one of the biggest factors associated with the development of osteoarthritis following ACL reconstruction.

The purpose of this article is to review some of the many methods of assessing and treating loss of knee extension range of motion to help maximize outcomes following knee surgery or injury while minimizing long term complications.

 

Assessing Loss of Knee Extension Range of Motion

There are many ways to treat loss of range of motion in the knee, however, proper assessment of range of motion is even more important.  A certain degree of hyperextension is normal, with studies citing a mean of 5 degrees of hyperextension in males and 6 degrees in females.  Simply restoring knee range of motion to an arbitrary 0 degrees is not advantageous.

The most important factor in assessing loss of knee extension range of motion is looking at the noninvolved knee.  As simple as this sounds, this can not be overlooked as you need to establish a baseline for what is “normal” in each patient or client.

The first thing I look at is simply grasping the 1st toe with one hand to lift the foot off the table.  My proximal hand can stabilize the distal femur.  This is a quick and dirty assessment but I always recommend quantifying the available range of motion.

To accurately measure knee extension range of motion, you will need to use a towel roll of various height to assure the knee is fully hyperextended before taking a goniometric measurement.

Knee Hyperextension

Other aspects of assessment that should be performed when dealing with loss of knee extension range of motion should include patellar mobility, tibiofemoral arthrokinematics, and soft tissue restrictions.  Patellar mobility is especially important after ACL reconstruction using a patellar tendon autograft.  Any restrictions in patellar mobility can have an obvious correlation with restricted knee extension.  Scarring of the patellar tendon can restrict superior glide of the patella and full knee extension.

These assessments will help guide our manual therapy approach to restoring normal arthrokinematics and range of motion of the knee.

Documenting Knee Range of Motion

I took a poll of a large group of students coming through my clinic in the past and found that there was great confusion regarding how we document hyperextension of the knee.   Is + or – when defining a numerical value?

Let’s say that someone has a contracture and is sitting in 10 degrees of flexion and is unable to straighten their knee.  That would be +10 degrees of flexion, thus has to be -10 degrees of extension.  They are on two ends of the spectrum.

Still, using a + or – can be potentially confusing, so I have long taught my students that we should document range of motion using the A-B-C method.  Other authors, such as Dr. Shelbourne, recommend this method as well.

  • If a person has 10 degrees of knee hyperextension and 130 degrees of knee flexion, it would be documented as 10-0-130.
  • If a person has a 10 degree contracture and loss of full knee extension with 130 degrees of knee flexion, it would be documented as 0-10-130.
Using the A-B-C method eliminates the potential for confusion while documenting.

Treating Loss of Knee Extension Range of Motion

There are several ways to improve knee extension range of motion, however, if a person is struggling with this motion I have found that self-stretches, low load long duration (LLLD) stretching, and range of motion devices can be superior to us cranking of a already cranky knee!  Allowing gentle, frequent, and progressive load to the knee is usually more tolerable for the person, especially those that are sore or guarded in their movements.

The intent of this article is to discuss some specific independent strategies to enhance knee extension range of motion.  Other skilled treatments should focus on patellar mobility, soft tissue mobility, and other aspects of manual therapy for the knee as needed.   However, patients will need to perform stretches at home to assure good outcomes.

 

Self Stretches for Knee Extension Range of Motion

Two of the first stretches that I give patients following surgery are simple self stretches for knee extension.  The basic version simple has the patient applying a stretch into extension by pushing their distal thigh.  The second and slightly more advanced version, has the patient press down on their distal thigh while using a towel around the foot to pull up and simultaneously stretch the hamstrings.

Knee Extension Stretch

Towel Knee Extension Stretch

Similar to how we assess knee extension range of motion, you will want to use some sort of wedge under the heel to assure that you are restoring full motion.

 

Low Load Long Duration Stretching for Knee Extension Range of Motion

For the person that is having a hard time achieving knee extension, my next line of defense is usually LLLD stretching.  Several research articles have been published showing the benefit of LLLD stretching in achieving range of motion gains.

I prefer performing LLLD stretching for knee extension in the supine position rather than prone knee hangs (follow the link to learn why).  This has always been a more comfortable and thus more beneficial position for me.  To perform this exercise, place a towel roll or similar item under the heel to allow full knee extension and then a comfortable weight over the distal thigh.

Low Load Long Duration Stretch Knee

The purpose of this exercise is to be gentle and to hold the stretch for several minutes.  I typically use anywhere from 6 to 12 pounds and hold the position for at least 10 minutes.  If the person is fighting against the weight, then it is too aggressive.  Lower the weight and you’ll see better results.

Don’t forget that you can apply moist heat to the knee simultaneously for even more benefit.

LLLD Knee Stretch with Heat

Devices for Knee Extension Range of Motion

I am also quick to prescribe a range of motion restoration device for people that may be struggling with range of motion or are not moving their knee enough throughout the day.  I have tried some of the dynamic splinting in the past but found that many people would rather control and hold a sustained stretch rather than have the brace apply a dynamic stretch.

The two devices I have used and enjoyed are from Joint Active System (JAS) and End Range of Motion Improvement (ERMI).

JAS Knee Brace        ERMI Knee Brace

Both devices allow the patient to apply their own tolerable LLLD stretch at home.  This is helpful as frequent movement throughout the day is always beneficial.

Personally my criteria to use these devices is usually when I perceive the person will self-limit themselves and avoid motion.  I will get a device in their hands early so that they can move their knee more at home and have a feeling that they are controlling the restoration of range of motion.  We probably resort to using these devices when it is too late and the patient is already too stiff.

 

Conclusion

These are just some of the many ways to assess and treat loss of knee extension range of motion.  Considering how important it is to restore full knee extension after knee surgery, properly assessing early signs of loss of motion and effectively treating the knee to avoid long term loss of motion is critical.

What has the Biggest Impact on Outcomes Following ACL Reconstruction Surgery?

Loss of knee extensionIt is no surprise that loss of motion is one of the biggest factors in patient satisfaction following ACL reconstruction surgery, specifically loss of knee extension.  In addition to the limitations in functional activities that occur with loss of knee extension, we have also discussed some of the risk factors of loss of motion following ACL reconstruction.

Loss of knee extension has a dramatic impact on gait, muscle activity, and normal tibiofemoral and patellofemoral arthrokinematics.

Imagine not being able to straighten your knee out.  You can’t lock out your knee for stability.  You naturally will shift your weight to the other extremity and overload your other knee, hip, and probably even your back.  Your quad and hamstring never get to shut off and relax.  Your patellar tendon will probably be on fire, and your patella will always be engaged and taking stress.

I can definitely see why patient satisfaction would be poor if you had long term loss of motion following ACL reconstruction!

Impact of Loss of Motion on the Development of Arthritis

In addition to poor patient satisfaction, recent research has shown that loss of motion following ACL reconstruction also results in the development of osteoarthritis.  In a recent study in AJSM, Shelbourne et al followed 780 patients for a mean of over 10 years.  They showed that of the group of patients that had normal motion on follow up examination, 29% exhibited signs of osteoarthritis on radiographs.  Conversely, 47% of the group that showed loss of motion had developed osteoarthritis.

This makes perfect sense as your arthrokinematics, center of rotation of the joint, and tibiofemoral and patellofemoral contact pressure will be altered.

How Much Loss of Extension is Significant?

More importantly, the authors also showed that even a loss of 3-5 degrees of motion had a significant impact on both patient satisfaction and the development of early arthritis.  Those subjectives that exhibited greater than a 5 degree loss of motion had an even more dramatic impact.

According to DeCarlo and Sell, the average amount of knee extension in healthy individuals is 5 degrees of hyperextension, with 95% of individuals demonstrating some amount of hyperextension in the knee.

Taking this into consideration, we should challenge the common belief that 0 degrees of knee extension is “normal.”  Individuals with 5 degrees of knee hyperextension that only restored their knee to 0 degrees of extension after ACL reconstruction surgery have a significantly greater chance of developing early osteoarthritis.

Clinical Implications

Based on these recent studies, there are bunch of clinical implications that we should all consider.  Here are just a few that I thought of right away:

  • Timing of ACL reconstruction surgery and pre-operative rehabilitation is important to settle down the knee, reduce swelling, and most importantly restore range of motion.
  • Knee extension should be restored as soon as possible after surgery, and should be one of the focuses of the initial postoperative phase
  • Even a small 3-5 degree loss of either extension of flexion range of motion has a significant impact
  • Most patients will have a certain degree of hyperextension, restoring a person to 0 degrees of knee extension is likely not enough
  • For those training post-ACL rehab clients, keep this in mind if the individual does not have full motion.  Advancing to exercises with high tibiofemoral and patellofemoral compressive and sheer forces before achieving full knee motion should be performed with caution.
  • Each patient should be assessed individually and range of motion should be restored to their unique assessment
This information also shows the importance of skilled therapy following ACL reconstruction, despite some of the studies that may show that home exercise is equally as effective.  If loss of the motion has the biggest impact on outcomes following ACL reconstruction, the development of osteoarthritis, and the subsequent health care costs, this strengthens the need for skilled manual therapy during the postopertaive rehabilitation process.

In regard to what to do with the tight person, I’ll work on a future post that discusses how I assess and treat loss of knee extension range of motion, but in the meantime I would love to hear what you think about this information and what you do with these patients.

Ankle Dorsiflexion Mobility Impairs the Lateral Step Down Test

Deficits with ankle dorsiflexion mobility can have a dramatic impact on functional movements such as deep squatting, lunging, and the lateral step down.  If you are familiar with the functional movement screen, you know that this is taken into consideration when a person does not grade out with a perfect score on many of the tests.

The Lateral Step Down Test

lateral step down testOne component that I have always felt is missing from the functional movement screen (FMS) is assessing the lateral step down.  I understand that the FMS needs to be applicable to a large variety of people and that the hurdle step test is included, but I have always felt I gain additional information from using the lateral step down test, especially in high level people.

I feel that the lateral step down test is an important test to include in your movement screening as it is often a movement that is dysfunctional in people with patellofemoral pain, patellar tendonitis, ACL injuries, and other lower extremity injuries.  During the lateral step down movement, the body is challenged in a very dynamic position to produce a combination of lower extremity strength, foot and ankle stability, core stability, and probably most importantly the ability to eccentrically control or decelerate the weight of the body.

A common finding during the test is the person that can’t resist medial displacement of the knee, resulting in hip adduction, hip internal rotation, and pronation at the subtalar joint.  This places the individual in a very disadvantageous position and makes them more susceptible to lower extremity injuries.  When analyzing people with this dysfunctional movement pattern, weakness of hip abduction and external rotation is commonly found.

Ankle Dorsiflexion Tightness Alters the Lateral Step Down

Ankle Dorsiflexion TightnessA recent study in JOSPT has found that ankle dorsiflexion restrictions can also cause poor quality of movement during the lateral step down test.  Examiners studied 29 healthy women and coached them through the lateral step down test.  The subjects were graded on the quality of their lateral step down with a 6 point scale.  Results showed that subjects that performed poorly in the lateral step down test had a significant amount of ankle dorsiflexion mobility restrictions when measured in both weightbearing and nonweightbearing.  Dorsiflexion was ~10 degrees more in subjects that scored well on the lateral step down test.

Interestingly, the authors did not find a correlation between hip abduction and hip external rotation strength with poor movement quality during the test.  I was surprised by this finding but realize that there were some limitations of the study, such as the use of healthy subjects that were coached well on technique.  I continue to believe this as experience and other past research has shown this, perhaps the limitations of the study can help explain.

In my experience, the three areas that I have focused on when someone does not score well on the lateral step down test are:

  1. Hip weakness, specifically hip abduction and hip external rotation
  2. Subtalar pronation
  3. Core stability

But the results of this study are going to make me assess ankle dorsiflexion a little more closely.  It makes sense that if ankle mobility is limited, the body would have to compensate to perform the task.  In this example, to achieve greater depth of motion while stepping down, the hip strategy observed was potentially due to the lack of ankle dorsiflexion.

In your experience have you seen this?  How many people incorporate the lateral step down test in their functional movement screen, and why or why not?  The results of this study should show us that ankle mobility, specifically ankle dorsiflexion tightness, can have a profound effect on the lateral step down test.