Yesterday, I got refit at my local bike shop to see if my positioning or cleats needed any adjustments before I started using my indoor trainer in earnest as part of my knee rehab. My pedal stroke and tendencies have changed quite a bit after the surgery, so some adjustments were needed.
I've had a couple of different bikes set up on the trainer since the total knee surgery, but I wanted to set it up with my primary road bike for the winter. The first bike I had on the trainer was a hybrid with big, flat "platform" pedals and a comfy seat, but as my range of motion has improved, I'm ready to put my road bike on there. With my road bike, I use a Speedplay clipless pedal system which secures my shoes to the pedals, and since the alignment of my left leg is now a whole lot straighter than before (see pic of "old" knee at right), I wanted to get my positioning looked at again before riding this bike. So I stopped by The Bike Hub in DePere, Wis., recently and set up an appointment with co-owner Rebecca, who is the shop's bike fitter. DePere is just 3 miles down the road from my house in Green Bay. The shop has a great location right off the Fox River trail.
For three years prior to my surgery, I've been using cleat shims to compensate for the valgus deformation of my arthritic left leg. Basically, a cleat shim (see pic of one these products at left) compensates for misalignment in your pedal stroke and in the way that your foot/shoe applies force to the pedal. These shims come in various slants depending on what needs to be corrected. I see that you can buy cleat shims online, but I wouldn't recommend it unless you are trained in bike fitting. Adding shims should be done as part of a bike fitting or cleat-fitting session with an expert bike fitter.
Pre-surgery, I tended to bow out my left leg quite a bit when pedaling, and the shims I had been using reduced that tendency. My right leg and pedal stroke have always been very good, with no shimming needed. Last spring after I moved to Green Bay, I had Rebecca at The Bike Hub review my cleat fit and cleat shims, and we made some changes then that got me through last spring and summer with no significant knee pain from cycling.
Since my knee is much straighter now, the first step was to remove the old cleat shims in between Speedplay cleats and bike shoes. Rebecca first did some measuring and assessments, including a look at the way my feet naturally hang. Then I got on a stationary trainer to examine my pedaling motion. Rebecca even used a laser light positioned a few feet in front of the bike to see how my knee was tracking while pedaling. This revealed that I needed some shimming, but slanted toward the other side because my stroke now had a slight tendency to move inward toward the bike frame's top tube. My range of motion remains pretty limited, which probably effects my ability to pedal a consistently smooth up/down stroke, so we agreed it's probably a good idea to take another look in a few months. For now, the pedaling motion feels fine and looks pretty good after this initial refit.
I'm definately planning on getting a fuller refit in about three months after my swelling goes away. It would be a good time to upgrade my pedals to a newer Speedplay model that allows for more adjustment in what's called "float." Unlimited "float" felt good with my old arthritic knee, but if the new knee feels strong and really solid in three months, I'd like to be able to limit the float to get a more efficient pedaling stroke.
I'm thinking most any avid cyclist with knee problems already knows about the benefits of a good, professional bike fitting. To anyone unfamiliar with what a bike fitting can do, take a look at this article from the Nov. 19, 2008 New York Times. Bike fittings can seem sort of expensive, but they are well worth it to avoid injury and increase your comfort level during and after rides. I think bike fitting is even more important when recovering from knee surgery, back surgery, or any injury that impacts your cycling motion, especially if you're on a clipless pedal system. Anyway, I'm all set up to pedal away with confidence. I just have to remind myself to take it easy (lighter spinning) on the bike, and in no way neglect the other types of strengthening and range of motion exercises in need to perform to rehab the knee properly.