Muscle Length Assessment and Treatment Related to Patellofemoral Pain

Original Editor - Stacy Schiurring based on the course by Claire Robertson

Top Contributors - Stacy Schiurring, Jess Bell and Kim Jackson

Introduction

I want to chat to you about muscle length with respect to patellofemoral pain. So, we're going to work our way through different lower limb muscle groups and we're going to look at, biomechanically, why is it relevant for each one that we assess it? How should we assess and test for the muscle length? And ultimately, what we can do to treat.

And often, I like to think about patellofemoral pain as a cumulative load. So, it's okay for a few steps, but what if you walk for a mile or run for five kilometres? What happens accumulatively? And so, these subtle changes in load can add up accumulatively to quite a lot more load.

So, I want to be clear. There's nowhere near as much literature underpinning the flexibility work as there would be for quadriceps or hip strength, for example. But there is some, and I think what we can do is we can look at our basic principles of anatomy, biomechanics, exercise, physiology. We can look at what we know about changes in tone; we can look at the evidence, some of my work that is showing changes in the muscle architecture; and we can listen to the patient's narrative. So, if they're talking about cramping, tight muscles, or if they're getting pain in passive positions, there are big clues there aren't there that the muscle length really might be as issue?

So, do I give out flexibility work for all my patellofemoral pain suffers? No, but do I give out stretching regularly? Yes. So, it's back to listening to the narrative, clinically reasoning, thinking it through and really trying to come up with something that's very bespoke for the patient.

For a review of the gait cycle, please read this article.

Hamstrings

Why is it mechanically relevant to assess?

• Tight, tense, and shortened hamstrings can pull the knee into excessive knee flexion. This can result in a greater knee flexion moment at initial contact or heel strike part of the gait cycle.
• Any resulting increase in knee flexion will increase the patellofemoral contact pressures. Therefore it is important to avoid the situation where the tibia is being pulled back and there is enhanced knee flexion.

How should we assess and test for the muscle length?

• It is important to assess hamstring length in conjunction with stride length
• Bedside clinical exams: sit-and-reach, straight leg raise
• It is important to assess and compare the muscle length of both hamstrings. The rehabilitation professional should also take the patient's relative flexibility into consideration, ie: is this patient's body overall flexible or tight. This will help determine the patient's muscle length norm.
• Other muscle groups to assess: gluteal extensors
• Clues from the patient interview or past medical history: a patient may state that they stretch regularly but have not noticed any change in their flexibility, histories of repeated injury to a muscle group might mean that it's got more scarring in the intramuscular matter, having regular repeating injuries.

What can we do to treat?

• The literature gives little insight to the duration or frequency of stretching
• Consistent, regular stretching that the patient will be able to complete is key. Talk about the patient's schedule and lifestyle and help them create an exercise programme they will be able to stick to and faithfully perform. Create easy, pragmatic exercises the patient will most likely complete.
• Types of hamstring stretches: (1) standing static stretch, (2) dynamic stretching, (3) hold-relax (also known as contract-relax).
• There is some literature support that dynamic stretching is slightly more effective. Hold-relax stretching tends to decrease muscle tone which allows the stretch to be deepened. However, it is important to create a n exercise programme that is best suited for the patient.

To learn more about the types of stretches and how stretching effects muscle anatomy and physiology, please read this article.

Quadriceps

Why is it mechanically relevant to assess?

Now, let's think about quadriceps. So, there might be some clues here in their history that quadriceps flexibility is an issue and my talk on subjective examination looks at this. So, tying in with that, what are they like when they sit still with their knee flexed? If that is a problem to them, there's no muscle strength issues either at rest, no gluteal strength issues at rest, no foot posture issues really at rest, no load issues. So, lots of the things that we would typically look at are an irrelevance, but if sitting still is painful for them, then we need to think about quadriceps length.

How should we assess and test for the muscle length?

So, when we sit for a prolonged period with tight quads, we have a large compressive vector through our patellofemoral joint, which might be tolerated for a short while, but after a while that pressure in the subchondral bone can go up and up and up and they get to the point where the only way they can alleviate that pressure pain is to straighten out their leg. So, if we are suspicious that the quadriceps length is an issue, then what are we going to do? Well, we need to objectify that, we need to assess it. And I have a big fan of the modified Thomas test. I think it's a really useful, easy-to-do assessment that doesn't take long, it doesn't need equipment, and yet is very revealing. And in some instances, the patients will say, that's my pain when you go into that position, or certainly when you passively flex the knee. And just to remind you, if you flex the knee and the hip comes into more flexion, that's reminding you that part of the tightness is rectus femoris. If the hip does not flex, then it's more tightness in the vastii. So, if we've got some quadriceps tightness, the knee won't just hang at 90 degrees with gravity. It will hang out around about 45, 50, 60 degrees. So, it's hanging on that tension. And often when you take them passively to 90 degrees, you can really feel the level of resistance there. And of course, when they then sit at 90 degrees, that's what they're facing. They're facing that level of resistance and that level of compression through their patellofemoral joint. And for some patients, you know, cinema sign is one of the worst problems. You know, they dread long journeys, dread going to the cinema or theatre because sitting still with their knee flexed is just too difficult to cope with.

What can we do to treat?

So, it's important to assess this quadriceps tightness. And if we find it, there is inherently a little dilemma immediately. If I ask someone with a sore patellofemoral joint to do a classic quad stretch, take their foot to their bottom a couple of times a day, guess what will probably happen to their patellofemoral pain? It will probably get a bit worse. They won't like the treatment. But if they are that tight, they don't need to go into that much knee flexion. So, what I get them to do is I get them to stand with a chair behind them, pop their foot on the chair, and stand tall and I say, "imagine a helium balloon attached to your breastbone, pulling you up". And that change in posture tends to bring the pelvis forwards and tension up the quads and that usually is enough, but it won't aggravate their knee. So, it's quite a useful little trick. If they're not irritable, you can also do hold-relax by getting them to push the foot down into the chair and try and use that as the isometric hold for 10 seconds.

Okay. We can also look at flexibility gains with eccentric exercise. But as much as the literature helps us understand that, the pragmatics I find are that the patients won't tolerate those type of exercises that take them eccentrically to end of range. So, for me, I tend to be looking more to static stretching, possibly dynamic stretching, hold-relax.

A couple of other things too. There is some small amount of emerging evidence looking at dry needling to trigger points in the vastii as being preferential to sham needling. And also, we can look at foam rolling, and I've just finished a study recently, well I've done two studies, one's been published, one has just been accepted to be published. So, the first one looked at the architecture change on the vastus lateralis after a programme of static stretching. So, I looked at the architecture with the VMO, with respect to getting the VMO stronger, and we found that the stronger people got, the more angle, the bigger the angle of pennation, the fibre relative to the femoral axis, their fibre came down and we got that nice horizontal fibre insertion onto the patella.

Conversely, those people, particularly those who started with a tight, bulky vastus lateralis, after a programme of stretching, they had a more vertical fibre orientation. So, smaller angle. So, that was a great finding because intuitively that fitted with what I was seeing in my clinical practice. So, those people that come in with big, hypertrophied VL, like the cyclists sometimes we see, who you feed instinctively you want to get your hands on, that feels tight, tense, you want to stretch them out, they did well with stretching. And we replicated this study with foam rolling and found the same results. So, there is an anatomical, physiological underpinning for what is going on here with our stretching and our rolling. We need to choose our candidates carefully to make sure we're effective and we need to choose how, in particular, we're stretching, we are doing that.

Iliotibial Band

Why is it mechanically relevant to assess?

So, let's move on now to thinking about the ITB, very controversial anatomical structure. So, the ITB is, it's very strong and thick and it is not capable of changing length. Someone, Glen Hunter I think it was, did some work in the anatomy labs or bioengineering labs actually and found that it has the same tensile strength of steel. So, we're not stretching the ITB. Absolutely not. And having worked quite a bit in the dissection rooms and seeing the structure, it really is a very big, tough structure.

So, what are we doing? Well, don't forget higher up the chain, proximally it blends with muscles. So, its origins are contractile, and we've got tensor fascia lata and we've also got gluteus maximus. So, if there's tension, hypertrophy, shortening in those structures, then it's going to proximise the ITB. And that can do two things that are undesirable. The first thing is it can cause lateral tilt of the patella and the second thing is through its tibial attachment beyond about 60 degrees of knee flexion, it can externally rotate the tibia. And that's a problem because it brings round the attachments to quads and creates a functional valgus in other words, a big Q angle, which is going to overload the lateral patellofemoral joint and is clearly undesirable. So, we don't want tension in that top area.

How should we assess and test for the muscle length?

So, historically people have looked at the ITB using Obers but personally, I find particularly if I've got somebody bigger, particularly like a big male having them on their side, holding their leg, trying to manoeuvre them, and then I've run out of hands. I can't see their patella. I can't see their face adequately. I've always found it quite unsatisfactory actually and difficult to perform and not that helpful. So, I set about looking at supine hip adduction and we've just published this paper recently looking at ultrasound to measure the gap between the edge of the patella laterally and the femoral epicondyle, so the gap, and looking as you go into adduction at what happens to that gap and seeing the patellar tilt down. And, of course, in people who are tight proximally, that tilt is more aggressive and more enhanced. So, I put the patient in supine and get their other leg out the way off the plinth and block the pelvis and I just bring them into hip adduction and I'm looking how much change that creates at the patella. It will create a tiny bit of change on everyone but some people it's much more dramatic and in some patients, it will bring on their pain. So, then again, happy days, because then, you know, you've implicated proximal contractile structures in their patellofemoral pain picture.

What can we do to treat?

So, what are we going to do for those? Well, we can do some release work with something like a spiky massage ball on, particularly on TFL. Leaning against the wall against that can be quite effective. We can look at some stretches. So, crossover stretch in standing. Looping the leg over in long sitting for gluteus maximus. And I will try both of those stretches because sometimes it becomes very apparent that one is really tight, and the other is fine. And I struggle to differentiate that out with my testing, so I find by just doing the stretches, it's as good as I need to reveal which of these structures really need the regular stretching work.

And it's very interesting the number of patients who as part of that dialogue will say, "Do you know, as well as having my patellofemoral pain, I do get some pain at the side of my pelvis when I'm walking". Those are the patients that really tight, overactive in their TFL as well. So, it's really important that we're looking at that and a little clue in their subjective might be that they get cinema sign, but it's much more enhanced when they cross their legs. So, when they cross their legs and they go into hip adduction and tension those lateral structures, then it's demonstrating that their tightness in their ITB complex is a problem.

Gastrocnemius and Soleus

Why is it mechanically relevant to assess?

Okay. Finally, and by no means least is the calf. So, let's think about why the calf is important if it's tight. So, during the gait cycle, we've got initial contact with the heel and then in midstance, we want the tibia to be coming over the foot. Now, if they don't have more than plantigrade possible at the calf, they can't get past that point, can they? You've shown that on the plinth. So, therefore, to get past that, they've got to do one of two things. They've either got to excessively pronate, well, we know that's not a good thing for tibial rotation and patellofemoral pain, or they're going to have an early heel rise in their gait cycle. The heel flicks up and the knee bends. That's not good either 'cause it shoots the patellofemoral contact pressure up or they might have a bit of both. So, we don't want a tight calf at all. And in fact, there is literature to show that people with osteoarthritic patellofemoral joints have more bone oedema in their patellofemoral joint if they've got more knee flexion at the end of their gait cycle. So, there's only two things that are going to cause that. One is the tight calf, also tight hip flexors. If you have tight hip flexors, you can't get into hip extension. So again, you have to flex the knee to offload the hip.

How should we assess and test for the muscle length?

So, it's really important to look at the calf and also, we need to make sure we're distinguishing between gastrocnemius and soleus. So, for example, a skier with a flexed knee is constantly working soleus. So, if they're getting patellofemoral pain when they're skiing, I'm going to be much more interested in soleus. So, looking at gastrocnemius with the straight knee, soleus with a flexed knee. We can do that in supine, or we can do a - for soleus, we can do a knee-to-wall test.

What can we do to treat?

So, following this through, if we have found the gastrocnemius and/or soleus are tight, then it's up to us to, first of all, look at causative factors and there's definitely a group that have slender build but with big calves. They often comment, "I stretch and stretch, and I just can't seem to get my calves to stop cramping and they're really tight". And I think those patients, it's worth having a look at their hip flexor endurance, because if they're not pulling through at all from their hip flexor, they'll be push, push, push from their calf during their run.

So, looking at causative factors. So, if we want to treat, we again have a similar array of choices. We can do some release work, they can foam roll their calves if they're thick and tight, we can look at dynamic stretching, maybe on and off the step, up and down. Remember knee extension if it's gastrocnemius, knee flexion if it's soleus, or we can use that same off the step position statically for static stretching. Or we can use stride standing, forwards lean against a wall. Really, it's whatever works for that patient.

Resources

Clinical Resources:

• Handouts for special tests

Additional Optional Reading: