My New Leg

Now it was time to go back to the shop, try the test socket and find out what feet Wayne ordered for me to try out. In an earlier posting, I included an email I sent to Wayne listing the feet I would like to try: the Vari-Flex from Ossur (previously Flex-Foot), the Endolite Elite, and the Ohio Willow Wood Pathfinder.

Even after all these years, I still find it a bit strange to think of feet as having brand names and models. It’s simultaneously intriguing and alienating to think of a part of one’s body as a consumer product…

At any rate, when my friend Dara and I arrived at the shop, Wayne showed me the feet he had ordered for me.

And, of course, I still had the Renegade I’ve been wearing on my current leg that we could use for the sake of comparison.

Wayne told me didn’t order the Pathfinder for a couple reasons. It’s a tall foot and it turns out I don’t have enough clearance to wear it. Plus, Wayne has a low opinion of the foot from previous experience with other patients and suggested it wasn’t worth trying even if I could.

The first foot we tried was the Elite. Wayne attached the foot to the test socket and I donned the leg and stood up.

Prosthetic feet have different heights, which can make it difficult to swap feet with the same socket. The height was a bit short with the Elite foot, so Wayne got out an adjustable height discrepency measuring device (i.e. telephone directory) so we could determine how much adjustment was needed to even out the length of my legs.

Here’s a close shot of the Elite foot, with the plastic footshell removed, and one of me testing the dorsiflexion of the foot and seeing how far I could comfortably bend the foot. While it felt nice and had some multiaxial (movement in different directions) play when standing on it, I did not like walking on it.

Although I have walked on many different kinds of feet, I have come to prefer feet with a long keel (the forefoot and “toes” of the foot) and a smooth rollover. I walk quickly and take relatively long strides. A longer keel offers more resistance as I roll over the foot and gives me the sensation of having a longer foot. When I spend more time rolling over a long keel and then get a bit of spring as I lift off my toes, it’s easier to take long strides at my preferred pace.

When I walk on a foot with a shorter keel, it feels like the foot is too short: almost as if the prosthetic foot has had its toes amputated. I get the sensation of falling off the foot after mid-stance rather than rolling over the toes. I walk slowly, feel as though I’m limping, and find it generally unpleasant.

I also like a smooth rollover, meaning a continuous transition from heel strike to mid-stance to toe-off. Just as I don’t like the feeling of falling off my foot, I don’t like catapulting over one that’s too stiff either, as if the toes were too long. And I don’t the feeling of getting stuck on a flat foot, where I roll over the heel and can just feel the foot slap on the floor and stay in mid-stance… without every quite rolling onto the toes.

For now, though, the Elite felt like a short, flat foot. It gave me both the sensation of falling off a short foot with no toes and the feeling of a long flat spot in the middle of the foot. While I will probably prefer something like this later in life when I’m taking shorter steps and need the increased stability of a flat foot, it didn’t take more than a few trips through the parallel bars to figure out I didn’t much like it now.

So we moved onto the next foot, the Vari-Flex. It was developed by a company called Flex-Foot, which was recently bought out by Ossur, a prosthetics company from Iceland. The company was started by an amputee and was one of the first to make energy storing feet. Besides the Vari-Flex and other models, they also make the Cheetah model used by many sprinters. I’ve always liked their feet, but haven’t tried the Vari-Flex for years.

Wayne used an Allen wrench to remove the Elite foot and attach the Vari-Flex to the test socket, and then I walked through the parallel bars to try it out.

At first, it felt as though I were catapulting over the foot. It was a bit too plantarflexed, meaning the toes were pointed down too much. Wayne used his Allen wrench to dorsiflex the foot a bit more…

…and away we went to field test the Vari-Flex on the streets of San Francisco. I should note that it is very unusual for prosthetists to let their patients leave the clinic wearing a test socket. Wayne trusted my judgment, I trust my ability to know if the leg or foot suddenly posed a hazard to me, and we agreed I wouldn’t hold him responsible if I fell or otherwise hurt myself.

I was very lucky to have this opportunity and such a trusting prosthetist, but it’s a shame this isn’t more commonplace. Although many prosthetists, including Wayne, have architectural elements such as stairs and ramps in their fitting rooms, there’s a big difference between walking in a fitting room and the outside world.

The terrain is different. Indoor floors are perfectly flat, while sidewalks are graded (2% for drainage) and uneven. There’s sand and gravel, treeroots and curbcuts, bumps and cracks, hills and slopes, and all the little obstacles that prosthetic feet have to surmount or circumvent.

We also walk under different conditions. When I walk in the parallel bars at the shop, I am unencumbered and focus on walking for a short distance. In my daily life, I’m often carrying something or someone, and sometimes both, e.g. one of my daughters and a diaper bag.

We don’t just walk. We walk in a context, and it’s part of the fabric of our everyday lives.

I am writing this at an internet cafe in the Rockridge neighborhood of Oakland. In order to get here, I had to walk up a slope over some really cracked sidewalks while lugging my laptop computer in a bag over my shoulder. A fitting room isn’t very indicative of these real world conditions.

After walking a few blocks to get my bearings on the foot, I decided to put it through its paces by running…

…leaping off some steps to try out the shock absorption…

and trying out somebody’s stairs.

After all that, I began to feel something a little loose, so we stopped. I wiggled the foot (left) and found it had loosened a little, so I used Wayne’s Allen wrench to tighten it up before walking the long way back to the shop.

I liked the Vari-Flex. It felt much like my current Renegade foot (a good thing) but perhaps a bit firmer in the heel and springier in the keel. It’s generally a good sign when a foot feels nondescriptly normal, rather than remarkable like the Elite.

Back at the shop, Wayne removed the Vari-Flex and attached the Trias foot. I briefly tried it out in the parallel bars and then headed outside to abuse it with some running and more leaping from steps. This may not have been the smartest or safest way to test shock absorption and how the foot handled sharp drop offs, but seemed like a good idea at the time.

After walking around a bit more, and feeling as though the foot was still a bit too short, we headed back to the shop.

Wayne devised a couple shoe inserts made of thin foam rubber, one 3mm thick and another 5mm thick, so I could adjust the height of the test socket accordingly as I tried out the different feet at home. He watched me walk on my current Renegade foot to check my gait after trying out the different feet and sent me home with a bag of feet to try for the next couple weeks.

But first, Dara and I stopped off at the fabric store so I could go shopping for decorative cosmesis for my new leg. And not just any fabric store, but Mendel’s Art Supplies on Haight Street, which has an amazing selection.

My first prostheses were exoskeletal, meaning the structure of the limbs was external. They were plastic shells, shaped to look like legs, and were painted a vaguely Caucasian flesh tone. They were kind of clunky and resembled mannequins more than anything.

My last couple prostheses have been endoskeletal, meaning the limb is made up of modular components held together with hardware and no external structure — just like the ones pictured in this blog. Prosthetists can wrap foam and cosmetic skin-like coverings around the components, but I’ve preferred to eschew the cosmesis in favor of the raw tech look of black carbon fiber and metal. There’s a trade-off in prosthetics between cosmesis and function, and I’ve opted for function.

But it’s also possible for prosthetists to laminate fabric around the socket so that even cosmetically unfinished limbs have a design wrapped around the socket. When I got my current leg, I wanted to wrap it in H.R. Geiger style artwork, but the cost of commissioning the art was prohibitive. But this time, I thought I’d pick out an interesting fabric design to have Wayne laminate into the socket, so we went to Mendel’s.

In the previous photo, I’m deliberating over two Dia de los Muertos designs.

I picked out two fabrics. First was this one of dancing skeletons from el Dia de los Muertos, the Mexican Day of the Dead holiday.

Second was this Japanese dragon tattoo pattern. Next step is to try out the feet and decide on a fabric.

You must be logged in to post a comment.