A Few (Hopefully) Final Thoughts on Structuralism and Knee Pain

I didn’t originally envision my recent thoughts on structuralism as a two-parter, but hey, I’m at the point now where I go with the material I get …

This blog of course is in semi-retirement, now that “Saving My Knees” is nearing its 15th birthday, and reader interest has understandably begun to wane. However, for some reason, over the last couple of months there has been a little upsurge in book orders, which always gets me thinking about the blog again.

I received a comment about my last post’s musings on structuralism. To recap, structuralism has been described as a school of thought that attributes the origin of musculoskeletal complaints to one or more biomechanical abnormalities. For instance, a structuralist may blame your mistracking patella for your knee pain (even though there are lots of people with mistracking patellas who have no knee pain).

I got a comment that raised some good, thoughtful points. Here it is, edited and notated, with some responses at the end: 

I agree with your point about structuralism. But the functional PT exercises get at something slightly different. Don't you think that the *way* we use our bodies should matter?(1) Let's say I sit at a desk all day for work. My movement patterns will probably be pretty damn different from a hunter-gatherer's. My muscle tone and activations will be different. This idea isn't about fixed (or mostly-fixed) anatomical differences, but about what muscles we use and how we use them.(2)

For example, my right knee has had issues on and off for many years. My right achilles, hamstring, and hip also have had mild injuries. It's possible it's a coincidence that everything is on the right side, but I think my body has been compensating for injuries, throwing off the whole system.(3)

In running, there are different types of running gait, some of which put more strain on the calves, others on the quads. Why do different people run in different ways?(4) There's going to be some fixed anatomical reason, but the muscle tone and activation will also influence running form. Tight ankles means someone is more likely to turn their feet outwards, for example. That can cause problems in the knee.(5)

(1) Does the way we use our bodies matter? Of course. It would be hard to find anyone sensible who would dispute that. If my favorite hobby is jumping out a 15-foot-high barn window, onto hard ground below, I’ll probably develop knee pain before long. Or, as a less extreme example, if I’m a sedentary desk warrior living in a snowy climate, and only get winter exercise from shoveling snow, I stand a good chance of developing back pain, during the cold months, from overusing flabby muscles.

(2) At least some of the ideas of functional physical therapy make sense to me. I wouldn’t argue with doing exercises that enable us to better handle everyday activities. I probably qualify as doing these myself. On workday mornings, for example, I do a few minutes of the “bird dog” yoga pose to keep my back strong. I tell people that I do exercises like this to prepare for sitting behind a desk for eight to ten hours. And I’m 100% serious.

(3) Could a body compensating for injuries cause more injuries? Absolutely. Use your body repeatedly in unnatural ways and pay the price. In the book I call these “compensation injuries.” I developed back pain in Hong Kong from sitting at work with my legs straight out, supported by an under-desk sling, in order to relieve my knee pain. That put too much stress on my back.

(4) Running form is a fascinating subject by itself. I ran cross country in high school. And the guy on the team with the weirdest running form – I can still see his arms swinging from side to side – was the fastest guy on the team. Anatomy, muscles, soft tissues, I’m sure there’s an interplay between them all that explains why someone runs the way they do.

(5) So, when it comes to running, I’m sure some of my own issues stem from being a pronator. That has implications beyond wear marks on the outer edge of my shoes.

Anyway, this may come as a surprise, but part of a structural analysis makes sense to me. For instance, as noted above, I used to be a runner.

Even though I have a good body for running, it’s probably not ideal. I’ve watched the truly elite runners. Even if I had their conditioning, their weight, their ability to process oxygen, I still probably wouldn’t be able to do what they do. And it’s probably for structural reasons.

We’re not all designed to run marathons, or even 10k’s sometimes. Even with proper training, certain body types may never be able to run 60 miles a week without problems, while others can. I recall the time I ran a half-marathon in Switzerland, and all the training, and the niggling pains, and thinking, “I probably don’t want to push myself into a race beyond this distance.”

So I think that, while healthy, we do operate within some kind of overall structural limitations. But where the structuralist story falls apart for me is when a runner develops knee pain, and a structuralist physical therapist discovers tight ankles, and exclaims, Ah hah! We need to stretch out those ankles, because that’s the problem!

I think this fails because:

(1) It can be easy to confuse cause and effect. To take a different example: you may have a weak right hip along with your right knee pain. But the answer isn’t just “strengthen the hip to fix the knee pain.” As Kelsey notes, “People with knee pain will almost always have weakness of the hip on the same side as the knee pain.” What he proposes: Fix the entire hip-knee-ankle chain together, using reduced loads, instead of trying to cure the right hip “imbalance” by strengthening it in isolation.

(2) But going back to the tight ankle: it’s virtually impossible to prove that the tight ankles caused the knee injury in the first place. Lots of things could have caused or somehow contributed to that knee pain; there are many forces feeding into the knee joint. Just because a therapist finds a tight ankle doesn’t mean that that was a prime mover for the resulting pain.

(3) But let’s suppose it was. Suppose the therapist has “God’s Diagnostic Tool.” And God’s Diagnostic Tool indicates that a tight ankle, over time, basically led to this problem. Then what do you do?

I think you’re still best served by an “envelope of function” approach to treatment. You need to back off your running and keep that knee within the acceptable envelope, moving it but not pushing it too hard, until it heals. And maybe you have to accept that you need to train more carefully, or you’re not built for say marathons.

I know, at this point, the structuralist would probably jump in to say, “And stretch that tight ankle!” But personally I’m a skeptic of stretching (but a big proponent of warming up). The fact is, people run for years with their tight ankles and other little muscular and tissue imbalances and they do okay, as long as they stay within their “envelope of function” ranges and don’t overtrain.

(4) Sometimes it’s just impossible to “redress” the imbalances that are found anyway. What if the PT thinks that the imbalance to fix is a too-weak vastus medialis oblique (VMO) muscle that needs to be stronger to stabilize the patella? So he prescribes VMO-strengthening exercises.

That sounds great except … they happen to be useless, as Doug Kelsey explains here:

People with knee pain, especially patellofemoral pain, are often told by clinicians to strengthen their VMO to improve the alignment and tracking of the patella ... But, since the VMO doesn’t have its own nerve supply, you can’t isolate the muscle from the rest of the quadriceps … this isn’t just my opinion. Cerny examined this in 1995 and found no difference between the VMO activity and the rest of the quadriceps for a variety of common exercises used to target the VMO.

Anyway, at the end of the day, I’m not saying that structure, imbalances and crookedness are always irrelevant. I’m just saying that, if I’m trying to heal from an injury, I think the idea of staying within an envelope of function and slowly increasing load, while getting enough movement, is generally going to be a more successful (and logical) way to treat the problem.

There will always be exceptions, naturally. But they don’t prove the rule.