Ep 270: Return to run success after ACL reconstruction, with Brendan Butler

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[00:00:53] Dr. Peter Robinson, running biomechanical deficits are quite persistent at the time of return to sport and may stay there for up to five years later. Dr. Peter Robinson, PhD These variables are associated with increasing a risk with osteoarthritis or cartilage degradation because we're starting to lower the joint thousands of times in a different way.

[00:01:19] Dr. Peter Robinson, PhD Hello, and welcome to JOSPT Insights, the podcast that aims to help you translate quality research to quality practice. Dr. Peter Robinson, PhD I'm Claire Ardern, the Editor-in-Chief of the Journal of Orthopedic and Sports Physical Therapy. Dr. Peter Robinson, PhD It's great to have you listening today. Dr. Peter Robinson, PhD Today we're talking about an important milestone in rehabilitation after an ACL reconstruction, return to running, which sometimes gets overshadowed by its more flamboyant sibling, return to sport.

[00:01:49] Dr. Peter Robinson, PhD Joining me to explore best practice in return to running is Brennan Butler. He's a sports physiotherapist from Ireland who's currently working at the Aspatar Orthopedic and Sports Medicine Hospital in Doha, Qatar. Brennan's a member of the Aspatar ACL team where he applies skills honed in Gaelic football, rugby, soccer and athletics. And if you're looking for more detail on what we cover in today's chat, check out Brennan's excellent article on return to running published in JOSPT Open.

[00:02:17] You'll find the link in the show notes. Okay, let's get started. Brennan Butler, welcome to JOSPT Insights. Brennan Butler, PhD Thank you. Thanks for having me. Dr. Peter Robinson, PhD Thanks for joining us today, Brennan. There's plenty of focus on criteria-based rehab progressions after an ACL reconstruction. Yet, we still see quite a few people using a time-based progression, particularly for the return to running milestone. And you're going to guide us through that milestone, particularly today, that progression and why we might start to think

[00:02:47] about return to running differently. Let's start with why return to running is such an important phase or stage of the rehabilitation after an ACL reconstruction. Brennan Butler, PhD Probably one of the questions your players or athletes will be asking after surgery is, you know, when can I start running? And when you do get them running, you know, it's a feel-good factor. They're up and running. They feel like themselves again.

[00:03:13] They feel closer to their sport. You know, their family or their coaches see them out running. So, you know, you want that process to run smoothly when they do get up and running. Unfortunately, it's a time where you might have an increase in pain or swelling. So, we want to make sure that we have the right capacity developed before they do go running. So, we have a nice process, not just by clearing the first run, but all the way right through to

[00:03:38] return to sport. We typically took a step back and looked at return to running as nearly like a continuum where we started asking you, well, actually, what are we returning to? That should determine our return to run criteria. And when they are up and running, we want to see how they are running by maybe doing an assessment rather than turning a blind eye to it. And the reason why the looking at it as a continuum has become quite important recently is that when we look to the

[00:04:08] literature, we can see that running biomechanical deficits are quite persistent at the time of return to sport and may stay there for up to five years later. Some of the key deficits that we see are reduced knee extension moments, reduced ability to absorb or propel power, and some kinematic stuff like not being able to flex the knee in the mid stance position. Underloading, so the joint is

[00:04:35] underloading when we go back to run. These variables are associated with increasing our risk with osteoarthritis or cartilage degradation because we're starting to lower the joint thousands of times in a different way. It's easy to fall into the trap of thinking running is such a natural activity. So many people do it. It's an easy progression. But I think what I'm hearing you say is setting that return

[00:05:02] to run up correctly, if you can do that well, then you're really setting the athlete up for much longer functional success and performance success potentially and setting that knee up, in this case after an ACL reconstruction, to have a much better time and a much better recovery. Have I got that right, Brendan? Absolutely. One of the main things is obviously keeping the main thing the main thing. Early days in regards to getting your capacities with strength and strength will probably

[00:05:29] be the main factor throughout your rehabilitation. So making sure that you're developing your strength and developing your playhouse that they have the capacities to start that run and starting them early to prepare for that run or first run. Preparing your running mechanics to make sure that they're going to accommodate those loading cycles that they're going to endure is really important. I also like how you're framing return to run as part of a continuum as opposed to a binary,

[00:05:56] yes, you're ready to go. No, you're not ready to go. We're hearing that a lot more when it comes to returning to sport. And I like that you're bringing that a little bit earlier on into our thinking that we need to approach the return to run in a much more function-based, criterion-based approach as opposed to the binary time-based approach that we've often been using. Which brings me to, you've been leading work to capture what many clinicians around the world do through this return

[00:06:23] to run continuum and how people have been typically doing this progression to date. What have you found in all of this survey work? We sent a survey to all the attendees at the ASPDR ACL conference based on the five components of return to run which are patient reported outcome measures, clinical measures, strength and functional criteria. We also asked them what was their characteristics of a

[00:06:53] first run in regards to time and speed. And we also asked are they doing running assessment? How are they doing this and what are they measuring? So the three key points that I talked about on the continuum. As you said, the research has primarily been saturated around that three-month timeline. So we wanted to get an understanding of what our clinicians currently doing now in regards to return to run. We wanted to compare the clinician answers against the recommended return to run literature.

[00:07:21] And what we found there was variability in the answers. So there was about 36% of people not using patient reported outcome measures. Only 16% were using an IKDC which is the only validated measure that we have in regards to return to run. Most clinicians were using the timeline of 12 to 14 weeks. Although 25% were reported not using a timeline at all, which was probably good to see that they're shifting towards

[00:07:49] criteria-based progression than just time alone. There was agreement in clinical measures such as pain, effusion and range. And when it came to strength, they preferred to have higher LSI percentages, typically looking towards 80% LSI on isokinetic concentric testing, which is interesting because the literature would say that it can take up to six months to get 70% LSI on quadriceps testing. And also there probably wasn't a lot of focus on the absolute value. So we know we can have,

[00:08:19] get a 90% LSI, but both our lins might be quite weak. So we were trying to point towards an absolute value or a peak number that says that, you know, our quads are quite strong to go running. One of the key points was, you know, 58% of the clinicians were doing some form of running assessment, but only 3% were assessing kinetics. So the variables that I previously talked about,

[00:08:45] such as knee extension moments, only 3% are assessing these despite it being the most prevalent or persistent deficits in the literature. And the problem with this is because it's quite expensive to assess kinetics. You often require an instrumented treadmill with 3D motion analysis to get it. So it's important that we find ways of assessing or running to make sure that we're starting to highlight these kinetics. Yes. So people are doing all sorts of

[00:09:14] different things, which is maybe a challenge and maybe an opportunity. And as you say, some of the challenge is in how do we translate some of these research-based metrics that we know are important into the clinic. And we'll come to that a little bit later. First, I want to get to, we've set out, or you've done a really nice job of setting out what people are typically doing, what types of metrics and progression, or what types of metrics people are using to help in

[00:09:41] this progression for return to run. What criteria do you suggest clinicians could use or should use to guide their return to running progressions after an ACL reconstruction, Brendan? Brendan? If we start with the first one per se, and we start to get an understanding of what we're trying to get back to. We want a general progression from early rehab right the way up to that first run. So we usually start in the pool doing some light movements, light plyometrics, some light running

[00:10:10] mechanics drills. And we start that even around three or four weeks. And it progresses on to an underwater treadmill, which often isn't that accessible, but it brings us to 50% body weight. And then around 12 to 13 weeks, we're going to the alter G running. But we only go to the alter G running after we've passed our return to run criteria. So for us, that's the time when we start in the running is when they go to alter G, or when they've passed the return to run criteria. The criteria that we

[00:10:40] typically look at is we want to have an IKDC greater or equal to 64. We also look towards making sure our clinical assessment is quite clean. So we want flexion greater or equal to 130 degrees. We want extension to be zero. But most importantly, if I can bring the knee to zero passively, I want my quads to be able to do that as well. So we really have to clean up distal quad strength, or contraction, because

[00:11:08] it'll come out in the wash later on in regards for functional exercises, if we don't have our distal quads quite strong. When it comes to pain, preferably we want zero. We're usually quite strict on that. And with the fusion, we want zero as well. But we can go to a trace as well, which is recommended in the literature. When it comes to quad testing, we're currently using a Nike D or

[00:11:32] ice kinetics. We're doing a concentric test at 60 degrees per second, and we're looking for 200% body weight. So that's the absolute value I previously talked about to make sure that we have the right capacity, you know, or 70% LSI and concentric testing. If you only have isometric kit, we're looking at 80% LSI for quads. And we can also look at functional stuff, such as single leg

[00:11:56] squat, nice and controlled 10 times, not using a hip dominant strategy on that. They're not bouncing up and down off a chair. And typically when it comes to hamstrings, we want 70% LSI. We're working towards 180% body weight as we go forward. And we've also added a functional task there of a glute ham raise up and down, nice and controlled. I think calf is something again, that's really,

[00:12:21] really important in this return to run phase where we want 20 end range calf raises with really good control. We're not jumping up into inner range. We have nice control with the knee extended all the way up to inner range and slowly back down again. This is really important to develop our vertical force. And when it comes to the sliost, so testing the calf in a bent position, we're a bit more sliost biased.

[00:12:45] We want about 1.6 to 1.8 times body weight on isometric testing. Functionally, we look at single leg pogos or single leg hops 20 times with good control and the heel is not hitting the ground or the knee isn't doing this anterior tibial translation. So this is when it comes back to the contraction of the distal quads needs to be really important to early days. And that can come across in the hip block

[00:13:10] position where we develop the co-contraction of the quads and hamstrings. We also get a contraction of the glute and also we're working on the medial hamstrings as they do an exercise where they typically go into a figure of four position with a band around their feet. Yeah. And it sounds like it's pretty high level. This is an athlete who's been doing quite a bit in the gym. This is not, you know, really early days. So these strength criteria are pretty advanced.

[00:13:39] Yeah, exactly. And this is where we want to make sure that we have these functional capacities before we go running rather than finding, rather than coming to three months saying, okay, it's time to go running. Let's talk about the first run session because you've really singled that out as a key progression in this whole return to running progression, Brendan. Why is it that you focus on the first run? It's the time when they move from gym-based exercises going on to the treadmill

[00:14:08] or the pitch or whatever way they're doing their first run. So to give context, if I did three sets of 10 repetitions in all the major muscle groups in the gym, that's about 550 loading cycles. Whereas if I actually do a conservative first run of 10 by one minute runs, that's about 1600 loading cycles. So it increases threefold. So it's really important that this first run we've prepared for it in a

[00:14:38] rehabilitation or running mechanics drills on the way up to it, because we understand that the joint can take high loads occasionally, but we're not sure if the joint can take low loads thousands of times or repeatedly. So we're trying to repair for that first run. When we do go running, you know, if we run with altered mechanics, there's a suggestion that even running for up to one to two minutes can change the cartilage behavior. So we want to make sure our capacity is right.

[00:15:04] And we also took a little bit closer look at even the speed of that first run, because if I increase my speed from eight to 16 kilometers an hour, that increases my moments by about 27%. So I'm actually increasing the force, the force going through the joint. But if I run at eight to 12, eight to 12 kilometers an hour, so as I increase from eight to 12, I can reduce my peak cumulative impulse by 12%.

[00:15:32] That's because I'm reducing the amount of cumulative load that the knee is taking if I run at a faster speed. Let's say if I was doing an interval or over a certain distance. So again, we're trying to get that happy medium that, okay, I'm going to have to reduce, increase the force a little bit, but also I'm going to run a little bit faster because the overall cumulative load in the joint is that little bit less if I'm at that speed. We also try and couple that with intervals, as I said, because it supports with our symptom management. It gives the joint a break in those first runs.

[00:16:03] One of the challenges, Brennan, as we've talked about, is translating the metrics that are collected in research with fancy equipment into a clinic where we may or may not have access to lots of fancy equipment. If I've got a basic setup in the clinic, I don't have an Ultra-G, I don't have an instrumented treadmill, what does it look like? And then maybe we can talk about the full bells and whistles Ferrari approach later. We can talk about kinetics all day and basically when it comes,

[00:16:31] it's very hard to get one of these machines, such as an instrumented treadmill. So we can do 2D analysis. So everybody has a phone or they can take a video on their phone of somebody running. Typically, some of the things that we see when we're doing a running assessment, such as reduced peak knee flexion, is associated with reduced kinetics or reduced loading through that joint. So that's the first thing we can use. We can all use our phone. Some of the stuff that we can see in

[00:16:59] 2D analysis is linked to some of the kinetic measures or underloading that we're seeing from an instrumented treadmill point of view, let's say. When do you do this assessment? Is it before the first run? We would actually typically do it firstly on the Ultra-G treadmill, only because it's quite enclosed and you can't really see the lower limbs well. But we get an idea of the head height and which limb is absorbing load and which limb is not. So if I don't have an Ultra-G, I would do it on that

[00:17:28] first run. So I take a 10-second video from behind the athlete or a posterior view, and then I would do a 10-second video in a sagittal view or from the side of the athlete. And let's say going back to the video of the 10-second video I've taken of the posterior view, I will pause the video in the mid-stands position of the involved limb. And I'll take a marker of the head height. I will compare it

[00:17:54] against the wall that's maybe in front of them. And then I'll take a pause of the video on the uninvolved limb. And what we often see is the head height drops a little bit further on the uninvolved limb compared to the involved limb. So we're starting to see, okay, there's a little bit of an absorption issue here, whether it be the knee or something else. But we're definitely starting to puzzle it together. I can make my way down and have a look at the arms. I can see that

[00:18:21] maybe the arm is swinging a little bit more than the other to trying to help the lower extremities get through in the flight phase. I can have a look at the trunk if there's an upper extremity sway. I can have a look at the hips to see if there's a hip drop or absorbing load through the hip rather than the knee. And also I can come down and have a look at the knee to see if there's valgus, anti-valgus position stuff or some poor control at the foot. So we usually treat what we see. So what we see, we treat. One of the key things, let's say I'm going to take a reduced knee flexion,

[00:18:51] angles again. This is one of the key things. And if we can clean that up, it's going to really help with our research down the line or what you might see at the end stage of running rehabilitation. So how I might really solidify that it is coming from the knee, I'm going to go to my sagittal view and I'm going to pause the video in the mid stance position on the sagittal view. And I'm going to have a look at my head height, but I'm also going to have a look at my peak knee flexion. And I'm going to compare

[00:19:16] that off the uninvolved limb again. Now we start to paint a picture that, okay, the knee is not flexing where we want to. And why is that? And it's another nice area to have a look at the ankle that maybe they're running with a protective strategy or with a plantar flexed strategy that we can become aware of. So again, that's something now I need to treat in my rehabilitation. And you know, if the mechanics are quite poor, it might be time to pause the running and clean up a few bits with our running mechanics

[00:19:46] and then get them running again. Let's talk about how you might address some of those deficits. If you're identifying deficits on your running assessment, how are you going to address them? And then have you changed anything in your practice to tackle some of these more kinetic deficits that you've seen persisting? The key thing here is that, you know, these running deficits that we see are quite prevalent. We're seeing them with most or a lot of the athletes at end stage

[00:20:13] rehabilitation. So it's really important for clinicians to get an understanding that there's a high chance that they're going to have running biomechanical deficits at the end stage of rehabilitation. So it's really important to start early, keep the main thing, the main thing, which is our strength. And we know from Knorr's work that we need to be preparing the quads to contract really fast. To prepare for that mid-stands position, we need to be getting the quads strong, which has a

[00:20:40] positive effect on our kinetics. But let's just take the reduced peak knee flexion in the mid-stands position, which is related to, you know, reduced knee extension moments or kinetics. Often we obviously start off with leg press or closed chain exercises and we protect the knee. You know, we lower the knee in a 90 degree position and push out and come back down to 90 degrees. But somewhere along that

[00:21:06] pathway, we really need to start working towards a positive shin angles. So what I mean by that is we need to prepare the knee to load in these positive shin angles positions. Because if we don't, when we go running, it's going to be very hard for the knee to actually absorb load into those angles if you haven't prepared it in your strength. Bring the knee over the toe with some of our compound movements. When we are up and running, we want to prepare the eccentric velocity of the muscles. So

[00:21:33] we want to be able to absorb load fast. So we often do drop catches, which is you're in a standing position and we drop into a squat really fast with our body weight. And then you can progress that to obviously doing that with load. And then you can progress that to a single leg. And as we go forward, we can start working towards landing based exercises. Land quick and quiet. So the more quiet I land, the more stimulus I'm going to put into my quads. And I want to be going down deep.

[00:22:02] I don't want to be doing it with a hip dominant strategy. I want to really prepare my muscle to take loads to those ranges. And then we can move forward into cyclical movement. So obviously running is a cyclical movement where we absorb loads of times or thousands of times. So we often go into a split lunge position and we get them jumping up and down in a cyclical pattern. Again, trying to cue getting that knee over the toe, trying to develop the ability to absorb load into those ranges.

[00:22:30] And lastly, we can do it in a single leg repeated jump. Again, coaching those flexion angles. This is all coupled with multifactorial rehabilitation streams around running mechanics, motor control and strength, looking at toe off drills in a running, wall drills, very mid stance position drills. So I think the most prevalent one is peak knee flexion. So I'm biased to that one. If you start cleaning up that one, if you start seeing it with your 2D analysis, you're in a

[00:23:00] really good place or putting them, that athlete in a really good place for the end stage rehabilitation. Dr. Seth O'Neill has been a guest a few times now on JOSPT Insights podcast. And what I've learned from Seth's work over the years is that the calf is such an important muscle when it comes to running and running mechanics. How do you approach planning your rehabilitation program to address the calf in return to running?

[00:23:26] Gas rock and sleazy is so important when it comes to return to run, particularly for the loads it takes, no matter what speed you're running at. So it's really important daily in rehabilitation that we're getting an understanding of what the gas rock and sleazy does through the running cycle. You know, it has a massive isometric force production. It has a massive vertical force production. It provides eccentric control. And also it obviously needs to have the endurance through that, through the running

[00:23:56] programs that we provide. So again, taking a step back, looking at the calf alone in ACL rehab, we need to probably try and hit all those key points. Generate force, where we look at, you know, heavy single leg isometrics, maybe in a Smith machine, holding for a couple of seconds, maybe five to eight seconds of trying to get a really good heavy load. Be able to do heavy production of

[00:24:21] force from maybe a deficit in the Smith machine all the way up through. And we often get our peak forces in the deficit. We might have too much load on the bar, so they're not getting up into inner range. So we want to actually hit those two different phases of the strength cycle when we're looking at trying to load the calf. And then also when it comes to the eccentric strength,

[00:24:46] we can have a look at the sleaze raise or the seated calf raise per se, to try and be a little bit more sleaze biased, to try and get really heavy loading through the sleaze to absorb load. And then obviously we need to be able to do loads of endurance stuff, such as the repeated hops we talked about, finishing off sessions, but doing extra reps on the sleaze or the gastroc or doing some hopping stuff. We've talked about quad, we've talked about calf. I think we should maybe give the

[00:25:15] hamstring a little bit of love here, Brendan. How would you suggest people think about planning for hamstring rehab as part of this return to running progression? When it comes to the hamstring, I think it's really important to be able to isolate the glutes that we're doing heavy glute ham work with good control. So we're able to do a posterior pelvic tilt and get a nice glute contraction. It's not about putting the load on. We want to be able

[00:25:38] to get a good control. We know how important it is for the push off of running mechanics. We also need to understand the importance of the medial hamstring. There's loads of work that there's a reduced EMG activity in the mid stance position, particularly some of the work from Athel Thompson and Aynar Anderson. So we want to be able to tackle that medial hamstrings, particularly in the prone position. So we're in a 90 degree position in prone and we're pulling the heel in towards the spine and

[00:26:08] we're really activating the medial hamstrings. And we know how important that is for the swing phase also of running. We look towards getting 180% of body weight, but we need to understand all the various movements like we talked about the calf that the hamstring does. That's really, really important for our rehabilitation. We started the podcast talking about how lots of people are still using the 12 week, 14 week time marker as their return to run progression criterion. It's clear

[00:26:37] from what you've been talking about, that's not enough. We have to move away from a time-based decision. You've given us heaps of practical suggestions for the clinic. Brennan Butler, thanks for joining me on JOSPT Insights. Thank you. Thank you very much. Thanks for listening to this episode of JOSPT Insights. For more discussion of the issues in

[00:27:01] musculoskeletal rehabilitation that are relevant to your practice, you can subscribe to JOSPT Insights on Apple Podcasts, Spotify, TuneIn, Stitcher, Google, or your favourite podcast app. If you like JOSPT Insights, help others find us. Tell your friends and colleagues and rate and review us. To keep up to date with all the latest JOSPT content, be sure to follow us on Twitter, we're at JOSPT, and Facebook, we're JOSPT Official. Talk with you next time.