Orthotics and Knee Pain? Big Study gets It Wrong…
Orthotics Knee Pain? I’ve blogged before on the debate over whether orthotics help knee pain or knee arthritis. A very large study that looked at foot positioning and knee pain recently found that there was an association for flat feet. This fit with a 2011 study showing the same thing. Now a New England Journal of Medicine article weighs in with what can only be described as a blind leading the blind conclusion, let me explain.
The study looked at lateral wedge insoles (orthotics built up on the outside) and their effects on patients with medial (inside) knee arthritis. It looked at 12 different trials that had already been completed (called a meta-analysis), that had a total of 885 patients. 502 of the patients had used orthotics, so they added up the pain scores between the groups with and without orthotics among all the studies. They did find a lowering of pain scores with orthotics. In fact the biggest drops in pain were in studies that compared no orthotic to an orthotic. However, the study concludes orthotics don’t work? Well the authors (who seem to have little understanding of biomechanics, but are quite good at math) felt that studies that used a neutral control orthotic were better designed and these studies didn’t show a significant difference when compared to wearing the actual orthotic. A control is where a patient is supposed to get something we know doesn’t work. There’s just one problem and it’s a common one in studies by university types who don’t regularly treat patients versus clinicians. The neutral orthotic itself is a pretty good foot stabilizer, meaning what they thought was a better control was actually a very bad one and more than likely a pretty good therapy. The authors, like some physicians, seem locked in a world of diagrams that don’t move. Meaning if you consider the foot at rest to either be straight (their neutral orthotic) or tilted (the lateral wedge insole), then their arguments to focus on the neutral orthotic as a control make some sense. If you however realize that patients do walk and in fact walking is the whole point of the orthotic, their argument falls apart. For example, its the movement of the foot as it hits the ground with hundreds of pounds of force that causes it to be unstable and to pronate or supinate (see above). It’s this movement that’s thought to impact the knee. So using a neutral orthotic provides great stability for the foot when compared to a normal shoe, which has no stiff platform on which to walk. It’s a pretty scary commentary on how out of touch our academic and publishing system can be that this paper made it all of the way through peer review at the prestigious New England Journal of Medicine without anyone asking this simple and obvious (to a clinician) question.
The upshot? First, I don’t prescribe many orthotics, so I really don’t have a dog in this fight. However, this large meta-analysis seems to show that orthotics work for knee arthritis pain (if you recognize that patients do walk), despite the erroneous conclusion that they don’t work.