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?

• Look for clues in the patient's subjective interview and past medical history
• If the patient reports pain in the knee with prolonged sitting with knee flexed, it is important to rule out: (1) no quadricep strength issues, (2) no gluteal strength issues, (3) no foot posture issues, (4) no load issues when considering quadricep length issues.

• 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.

How should we assess and test for the muscle length?

• Bedside clinical exams: modified Thomas Test.
  • When performing this test, when the knee is flexed and hip comes into more flexion, part of the tightness is rectus femoris; if the hip does not flex, then it is more tightness in the vastii muscles.
  • If the patient has some quadriceps tightness, the knee will maintain 45-60 degrees knee flexion. This signals that it is hanging on quadricep tension. And when they are passively moved to 90 degrees knee flexion, the examiner can feel the level of resistance in the muscle.

• Cinema Sign: Pain in the knee resulting from the compression in the patellofemoral joint with prolonged sitting with knee flexion.

What can we do to treat?

• Stretching of the quadricep is needed, but may need to be modified dependent on the patient's level of tightness.
  • If the patient is currently experiencing a sore patellofemoral joint, performing a classic standing quadricep stretch will most likely exacerbate their pain. This stretch can be modified by standing with a behind them, their foot supported on the chair, and provide verbal cues to "stand tall and 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 the patient is not irritated, they can perform a hold-relax (contract-relax) in the same modified position described above and pushing the foot down into the chair and perform an isometric hold for 10 seconds.

• The patient can also attempt flexibility gains with eccentric exercise. However, patients with patellofemoral pain often will not tolerate exercises that take them eccentrically to end of range.
• There is a small amount of emerging evidence looking at dry needling to trigger points in the vastii as being preferential to sham needling for patellofemoral pain management.
• 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?

The iliotibial band (ITB) can be a controversial anatomical structure. It is very strong and thick, and it is not capable of changing length.

"Gratz investigated the tensile properties of human TFL muscle and found similarities with those of “soft steel”, based on its tendon-like histologic structure comprised of an inconspicuous number of elastic fibers."

The origins of the ITB are contractile: the tensor fascia lata (TFL) and the gluteus maximus. If there is muscle tension or hypertrophy causing a shortening of the soft tissue structures, then it is going to proximise the ITB. This can cause two issues which can irritate the patellofemoral joint: (1) it can cause a lateral tilt of the patella and (2) through its tibial attachment beyond about 60 degrees of knee flexion, it can externally rotate the tibia. This ultimately will create a functional knee valgus moment, a big Q angle, which can overload the lateral patellofemoral joint.

• The patient may reveal that, in addition to their patellofemoral pain, they have some pain at the side of their pelvis when walking. This may indicate that they have a tight and overactive TFL. as well.
• They may have a positive cinema sign, but it is more enhanced when legs are crossed.

How should we assess and test for the muscle length?

• Bedside clinical exams: Obers test (however this can be a challenging position for patients to maintain and for the clinician to fully assess all needed angles).
• 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?

• Manual therapy for myofascial release on contractile tissues of the ITB
• Instrument assisted soft tissue release using a spiky massage ball, particularly on TFL.
• Leaning against the wall for provide pressure over contractile tissues of the ITB
• Trialing a variety of stretches which effect the contractile tissues and assess which give the best relief. The most affective can be added to the patient's home exercise programme.

Gastrocnemius and Soleus

Why is it mechanically relevant to assess?

• During the gait cycle, heel strike occurs at initial contact then the tibia must translate over the foot in midstance. Tightness in the calf muscles can prevent this from happening. To compensate patients with tight calf muscles will: (1) move into excessive pronation or (2) will have an early heel rise in the gait cycle. Both of these compensations have negative effects on the patellofemoral joint causing tibial rotation and patellofemoral pain, and increasing patellofemoral contact pressure respectively.
• 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.
• The patient may reveal that they stretch often but that their calves will not stop cramping or are always tight. In these cases, it is important to assess their hip flexor endurance. The patient may be pushing through their calves to compensate from lack of ability to pull through their hip flexors.

How should we assess and test for the muscle length?

• It is important to distinguish between the gastrocnemius and soleus.
• Assess for the gastrocnemius with the straight knee, soleus with a flexed knee. Testing can be done in supine or standing knee-to-wall test for the soleus.

What can we do to treat?

• Manual therapy for myofascial release or instrument assisted soft tissue release
• Foam rolling
• Dynamic stretching

Resources

Clinical Resources:

• Handouts for special tests

Additional Optional Reading: