Saturday, September 21, 2013

Wedge Shoe Inserts: Another Dud for Those Seeking Knee Pain Relief

One purpose of this blog is to celebrate what medical science shows works for knee pain while deprecating what doesn’t. (Note: with the caveat, of course, that even treatments/supplements/devices that have failed to withstand the withering scrutiny of scientific researchers will still have adherents who swear that “X” helps for their particular knees, science be damned.)

In that spirit (my addition in brackets), note the lead of this article:
Lateral wedge shoe inserts don’t appear to relieve knee pain in patients suffering osteoarthritis of the knee [that happens to be on the inner part of the joint], a new study finds.
Now, this wasn’t just any old study. Rather, it was the more powerful variety: a “meta-analysis” of existing studies. Such a review is potent, when done well, as those conducting it can choose to discount or disregard studies that are somehow flawed, leaving them to analyze the highest quality data. So the findings of a meta-analysis generally should carry more weight.

Why in the first place did anyone think lateral wedge shoe inserts would relieve knee pain?

Well, the thinking goes like this:

A wedge for the outer part of the foot will reduce the load on the inner part of the foot (and hence the inner part of the knee joint). Simple enough. And not such a far-fetched notion. It reminds me of the argument for kneecap taping to remove some stress from the injured area.

But when the researchers evaluated 12 studies involving 885 subjects, they found no proof that lateral wedges, inserted in shoes, were effective for knee osteoarthritis. So now you can save $10 to $500 (the price for wedges, from the cheapest off-the-shelf insoles to an expensive customized pair).

However, it may still make sense for doctors to recommend the inserts on a “case-by-case” basis, says Robert Shmerling, an associate professor of medicine at Harvard Medical School. “Even though the average response was no different between wedge insole users and non-users, individual response can vary.”

Yup. I’m a science-minded guy, but he’s got a point. Treatments that don’t work for 99 percent of us may work for some people in the other 1 percent.

For example, evidence is building that glucosamine is probably ineffective, yet some people still claim to be unable to function without it. I recently complained about physical therapists who prescribe one-legged squats for weak knees, which I think is pretty stupid, but a commenter said doing one-legged squats fixed his ailing knees. If someone were to advise knee pain sufferers not to do jumping jacks while wearing a backpack full of lead, I’m sure someone else would protest that he healed his bad knees by doing jumping jacks while wearing a backpack full of lead.

When it comes to ways to beat knee pain, it just goes to show you can never say never.


  1. Hey richard,

    I'm 24 and have had pfps/chondromalacia (or symptoms of) for at least 9 months. I tried all the stuff you did (having read your book) such as quad exercises, taping etc and none of which have worked. I'm curious about your symptoms (the only one seeming to be AKP + swelling). I have these + a clicking on extension of the leg. From your knowledge of the literature is this a common symptoms of pfps? Thanks for your book I found it inspiring and look forward to starting my own program.

    1. Yes, my symptoms were at first mainly burning around the kneecaps while sitting, but later, I also had burning while standing in one place. I also had some achiness and general "grumbling" in the joint. I did have some swelling, but it seemed minor.

      I think the "clicking" when bending or extending the leg is rather common. You could try Knee Guru, and ask the readers there how many have that symptom. I would guess quite a few. I had a little bit of a snapping in my left knee, as something seemed to slide over something else (to this day I don't know what was going on, and it was fairly minor anyway, so this symptom never went in the book.)

      Good luck starting your program. Check back in later and let me know how you're doing. Cheers!

  2. Hi

    In my case I find my customised insoles very helpful in relieving knee pain.

    Maybe I am in the 1%

    Keep up the good work

    1. I knew it! That only took four days. :) Well, if it works for you, keep wearing them!

  3. I thought this was an interesting blog post because in the past, my doctors highly recommended arch supports to help with me knee problem. using a skeleton, They showed me that this would prevent my feet from rolling in and thus prevent my knee from collapsing inward. So, I pretty much always wear insoles.

    However, the last couple medical people I saw about my knees didn't mention arch supports. Having been told for years about the importance of arch supports, I was surprised, so I even brought it up saying "Uh.... what about arch supports?" They basically said, "Meh. You can if you want to, but, if so, don't go for those custom ones. Store-bought ones would be sufficient."

    So, I thought that was very interesting! Personally, I do still wear arch supports in most of my shoes, but at least now I feel that its an option that I'm choosing, whereas previously I felt that I would be causing myself further damage if I did not wear them. Plus, I can have multiple pairs instead of having to swap the same one custom pair from shoe to shoe to shoe.