I can’t help it: I just love scientific evidence that thumbs its nose at conventional wisdom. Perhaps it is because professionals who unthinkingly hold and defend conventional wisdom are so irritatingly overconfident that it’s just a pleasure to be able to prove them wrong!
In 2004, a research group at the University of Connecticut let by Michelle Devan decided to try to figure out the effect of “structural abnormalities” on overuse knee injuries like iliotibial band syndrome and patellofemoral pain syndrome. In particular, they wanted to study women. Some evidence suggests that women get more such knee injuries, but it’s controversial, and the authors wanted to try to clear it up a little — and try to find out why there is a difference, if there is a difference.Some evidence suggests that women get more such knee injuries, but it’s controversial.
So, they did one of my favourite kinds of studies: they measured a bunch of stuff that every therapist in world “knows” is a risk factor for various knee problems, the usual structural suspects. In fifty young women athletes, they checked the tightness of iliotibial bands, the angles of knee joints, and the strength of their hamstrings and quadriceps. And then they waited to see who got what kinds of knee injuries over the course of the season.
Most health care professionals would fully expect the women with tight iliotibial bands to get more ITB syndrome, and the ones with some wacky knee angles to get patellofemoral pain syndrome.
But that’s not what happened!
Several of these young women got iliotibial band syndrome that season. One of them even got it both knees! But these experts determined that not one of them had tight iliotibial bands!
All the athletes with iliotibial band friction syndrome had a negative bilateral Ober test [their iliotibial bands were not tight].
Wow. All of them. That is some pretty amazingly counter-intuitive evidence. Pretty hard to hang onto the nice, simple, dogmatic idea that tight ITBs cause ITB syndrome, eh?
And exactly the same astonishing results were found with regards to knee angles and patellofemoral pain syndrome. The knee angle in question is the “Q” angle — quadriceps angle — and it is more or less gospel that a steep, womanly Q-angle is a risk factor for PFPS. (Wide hips increase your Q-angle.) However, the researchers found that “none of the 9 athletes who sustained an overuse knee injury had an excessive Q-angle.” Not one. Once again, wow. So much for the gospel!
For years, the strongest theme in my research and writing has been this idea that biomechanical factors are much less important in most injuries and pain problem than is generally supposed. So I really get a kick out of this research!It is more or less gospel that a steep, womanly Q-angle is a risk factor for PFPS, but not one of the women who got symptoms had a big Q-angle.
Now, to be fair, this study involved a fairly small number of young female athletes — not exactly a cross-section of the population — and there is some other evidence of connections between these injuries and structural abnormalities, and the researchers did find some suggestive evidence of a connection between knee injuries and the relative strength of the hamstrings and quadriceps. But the take-home message is simple: knees aren’t simple. You just can’t assume (or do therapy on the assumption) that a tight ITB is necessarily a big deal, or that a steep Q-angle dooms you to PFPS.
And, as usual with structural problems, even if you could be sure that they are important, half the time you can’t do anything about them anyway: just trying changing your Q-angle!
See Devan for complete bibliographic information, or you can read the whole scientific paper yourself. SaveYourself.ca also offers two advanced tutorials about iliotibial band syndrome and patellofemoral pain syndrome: