June 2009 Issue
My favorite business mentor, Peter Schutz, the former CEO of Porsche, said, "If you listen to your customers carefully, they will tell you what your job is." These days, this is truer than ever. Our customers are becoming more educated and more aware of their options, and they are demanding we do a better job at meeting their needs. Personally, I love it. Sometimes, we get really comfortable just filling prescriptions and don't think much about pushing the envelope, so when a customer demands more, the growth that comes from the struggle to meet their needs advances our art for everyone.
For instance, a few weeks ago, a friend of mine came to me with an interesting problem. You see, this guy is a cyclist. I don't mean that he likes to ride around the park on Saturdays—I mean that he is a cyclist. He rides every day. In addition to cycling, he plays tennis, and did I mention that he is an insulin-dependent diabetic? As the years of wear and tear started to add up, he eventually blew out the peroneus brevis/longus complex in his left ankle, and surgery was pretty much mandatory. Because of his diagnosis, we were concerned about the healing process and very conscious of the possibility of re-injury. After all, he agreed to the surgery so he could continue his active lifestyle.
Normally, cycling isn't a high-impact sport, and his surgeon was more concerned about the tennis, but in cycling there is a lot of repetitive stress and the potential for serious injury in the event of a crash. We knew we needed something that would offer substantial resistance to any varus moments but would also offer unrestricted dorsiflexion and plantarflexion. Although there are a few joints on the market that offer this level of function, all of them were larger and thicker than we could allow, especially in the area just distal to the joint axis. The brace had to fit easily into a cycling shoe—which is normally quite snug—so mass was critical.
Taking all these factors into consideration, our path was clear. We were going to have to prototype something. We started with a good, snug mold, which we knew fit well because we had made the post-op orthosis from it and added a lateral expansion to the foot plate to reduce the potential for irritation. Then we added a bit more clearance to the lateral maleolus, just in case. Now that our shape was determined, all we needed to do was design the device.
Clearly, we needed a material with a very high rigidity-to-cross-sectional ratio, and pre-preg carbon was the obvious choice. This material allowed us to very thoughtfully design the fiber placement to achieve wildly different characteristics within a single structure. We were able to make it extremely rigid in the frontal plane to control the varus moment and yet it was still flexible in the transverse plane, allowing it to accommodate fluctuations in the diameter of his lower calf. By altering the number of layers of the carbon, as well as the direction of the fibers, we plotted out how we wanted the device to behave in a given plane. The strength and rigidity of the fiber is relative to its long axis, so when we wanted to resist a force, we just aligned the fibers with the line of force to make it rigid in that plane but still flex in the opposing plane.
The next big issue was the articulation method. There are a number of joints on the market that allow free dorsi/plantarflexion and offer good strength in the frontal plane, but they all seemed to have too much mass in the area just distal to the joint axis, and they all required some sort of mechanical fastener. This not only made them difficult to fit into a shoe, but the mechanical fasteners also would have seriously detracted from the structural integrity that was key to the development of the lateral stiffness we wanted. The answer was obvious: we needed a prototype ankle joint.
We decided to use the carbon material as the "uprights" and developed a simple capture screw to hold the upper and lower components in relation to each other (see figure). By simply "pinching" the two halves together, we allowed the joint to rotate freely and still have a broad enough surface area so the device would have good lateral stability.
A thin foam liner in the proximal section and a few Velcro® straps were all we needed to complete the device. After a few minor adjustments during the final fitting, the brace was ready to roll. All in all, we had about two hours in the manufacture of the joint itself and another three hours in the production of the device. Not a bad investment, considering that we were able to produce something that met all of our customer's demands. The device is extremely thin, weighs next to nothing, offers excellent support in the frontal plane and very little resistance in the sagittal plane, and it even looks like a cool piece of gear.
In the past, demands like these have brought us advances like thermoplastics to reduce weight, articulation to make the devices move more naturally, and all sorts of decorations to make devices more attractive. So the question then becomes, what's next? Listen carefully, and your customers will answer that question.
Tony Wickman, RTPO, is the CEO of Freedom Fabrication, Havana, Florida. He can be reached at