Orthotics for knee pain: does pronation matter after all?
After last week’s discussion of the presumed death of the “pronation control paradigm,” I came across this new Australian study posted online at the British Journal of Sports Medicine about using orthotics to combat patellofemoral pain syndrome (PFPS — the nasty affliction sometimes known as “runner’s knee”).
The basics: 52 volunteers suffering from PFPS were given off-the-shelf three-quarter-length orthotics to insert in their shoes, with “built-in arch supports and 4 [degree] varus wedging.” They were then immediately tested to see whether they had less pain and could do more single-leg squats, step-downs and rises from sitting. The results:
Prefabricated foot orthoses produced significant improvements (p<0.05) for all functional outcome measures.
Hurrah! But here’s the rub:
A more pronated foot type and poorer footwear motion control properties were found to be associated with reduced pain during the single-leg squat and improvements in the number of pain-free single-leg rises from sitting when wearing foot orthoses.
Hold on, I thought we decided pronation and motion control don’t matter because they were just invented to make money for shoe companies! But that’s not what the authors think. In fact, they conclude that
foot orthoses have greater effects in poorer-quality shoes, possibly as a result of a greater potential to improve motion control properties.
Let’s step back for a moment. This study has a lot of limitations, not least of which is the fact that it wasn’t blinded, randomized or controlled. Also, if you look closely, the results are rather mixed. For step-downs, 57% got better, but 27% got worse; for squats, only 38% got better, while 20% got worse. Is this because orthotics made pronators better and supinators worse? Maybe… sort of… but not quite. Even the researchers had to waffle a bit in their discussion:
Although supportive of traditional theory, the associations of foot posture and change in foot posture with functional improvements were only fair.
So what can we take from this? Well, this study certainly doesn’t “prove” the pronation paradigm. But the fact that more than half the people in the study got immediate relief from a shoe insert tells us that monkeying around with joint forces is capable of affecting running injuries, for better or worse. Now, if you put those knock-kneed, flat-footed volunteers on a minimalist program, it’s entirely possible that they’d compensate for their weaknesses and imbalances and get rid of their knock knees and flat feet — eventually. Proper shoes, on the other hand (or in this case, orthotics), seem to cure the problem for some people immediately.
In a perfect world, we’d all be patient, careful, and dedicated to our exercise regimens — and no one would need running shoes. But this study suggests to me that the pronation control paradigm is able to offer quick fixes to some people, in some circumstances. As a result, while I expect the minimalism trend to continue to grow (and I’ll be glad to see that), I also don’t expect current running shoe technologies to disappear. Not because shoe companies are evil, but because some people will continue to want what those shoes can offer.