I have a lot to say on this subject. Much based on the experiences I
have had with my own sore knees and in dealing with foot bone
problems. But first, I know there are lot's of things that can go
wrong with knees, so don't assume the problems I have or those shown
on a web page are the ones causing your pain. The only answer I have
found is to find really good doctors, bike fitters, and perhaps
shoe-fitters, who can help you find the solution to your unique
situation.
In case you don't feel like reading the rest of what I have to say,
the short answer to your question about modifying the foot-pedal
interface is that you either modify some shoes (e.g. add a wedge on
top or underneath the sole, or just grind the sole to the shape you
want), or add an orthotic/custom footbed. Custom sports footbeds are
pretty easy to find here in Colorado, offered by ski boot fitters,
sports footbed shops, podiatriasts, and others.
That said, my knee pain is caused by the sort of sideways bending
shown on the web page you linked. When your knees move together when
bending under load, the kneecap is pulled towards the outside of the
joint which can result in damage to the cartilage tongue and groove
that holds it in place, and even dragging the cartilage over a very
sharp edge of bone on the outside of the ball that it rides on. If
that doesn't make perfect sense, suffice to say that imperfect
biomechanics can result in painful injury.
The sports medicine knee specialist who finally figured this out
thinks my problem is much more the result of hip joint limitations
than foot physiology. He did not recommend any sort of mechanical
solution. Instead, my goal has been to increase the relative strength
and recruitment of the vastus medius muscles (VMO), part of the
quadriceps on the inside of the leg. Flexing the VMO resists the
tendency for my knees to wobble inward when bending.
I have also seen more than my share of podiatrists, bootfitters, and
foot doctors. When I was about 12 years old, the tarsal bones in both
of my feet started to fuse so that I had a lot of pain and hobbled
around. After surgery, I needed to put orthotics in my shoes in order
to walk. Much to the surprise of the doctors, I recovered a large
degree of foot functionand nowadays love to walk barefoot. More
recently, I have had a couple of pairs of custom ski boots made up.
The first thing bootfitters want to sell you are custom footbeds. It
turns out I find very little difference with custom footbeds, and
great fitting boots (stock shell with ZipFit liner + misc tweaks) keep
my knees aligned and have all but eliminated skiing-related knee pain.
The point of mentioning this is that every podiatrist and bootfitter I
have dealt with has told me what a huge difference orthotics will
make, but in my reality the difference can be quite small.
Still, I am a big believer in bike fitting. The trick is finding
someone who is really good. I finally found one I like, and the
changes he made to my bikes were spectacular improvements, despite
having consulted a handful of other sefl-professed bike fitters in the
past (on the other hand, I spent a lot more on new components than I
had in the past). Guess what? He put those wedges designed to
compensate for forefoot varus on the cleats of my bicycle shoes.
Sorry if I have rambled. What I hope to have conveyed is the
recommendation to seek the best advice you can from expert sports
doctors, shoe fitters, etc. Don't believe everything you are told.
And don't assume a solution for someone else's problem will help
yours.
Ken
