Transtibial Shower/Swim Prosthesis

Richard L. Riley, C.P.
Prosthetic Consulting Technologies
Washoe Valley, Nevada

In my experience, the most useful ancillary prosthetic device for the trans-tibial amputee is the shower/swim prosthesis. Being an amputee prosthetist, I have always had the unique capability of having any type of leg I wanted. I personally utilize specialized prostheses for activities such as; downhill skiing, hiking, handball, and cross country skiing. I also have a peg leg for my pirate costume which is great for a party but highly unstable. Of all specialized prostheses that I have ever made for myself, the shower/swim leg has changed my life the most.

Arguably the most dangerous thing any of us does each day is get in and out of the shower or tub. For an amputee this is even more dangerous since they are either standing on one foot or sitting on a shower stool. Shower stools are safer than standing on one foot but my last two falls in the shower were from failed shower stools. Hopping in and out of the shower is also very risky and can be prohibitive if the shower stall has a tall lip. Tubs that have sliding doors can be very difficult to get in and out of since the track for the sliding door leaves no place to rest the knee.

Many believe that the answer is a permanent shower stool or bench that allows the amputee to enter and exit the shower safely. This can be an answer in the individual amputee's home. In fact, all amputees who have made the transition to independence have arranged their living space to adapt to their loss of leg. But what happens when they travel? Although many hotels offer accessible rooms, what about relatives or friends homes? What if the amputee has both legs missing? Environmental barriers, both real and perceived can create a situation where the amputee's world can begin to contract.

What finally convinced me ten years ago to make myself shower/swim prosthesis was my inability to play on the beach with my two infant sons. The sand and salt water were not good for my graphite foot and the shuttle lock mechanism would not tolerate those conditions. So I found myself sitting away from the beach watching my kids play. My shower/swim limb allowed me to sit in the sand, wade into the surf, and basically enjoy the beach as I had not done since prior to losing my leg.

What constitutes a shower/swim prosthesis? First, the components need to be waterproof or water resistant. That negates many prosthetic feet that have moving parts, bumpers, plates, and mechanical joints. These components will rust and deteriorate in a short period of time and then can then fail catastrophically when needed. The second feature of a good water prosthesis is the ability to keep the residual limb relatively dry and well suspended. Thirdly, the prosthesis should not be over buoyant. If the limb floats too easily then when walking in the water, it will always be trying to surface as the amputee takes a step.

I have made shower/swim prostheses for many years and have arrived at a simple set of components and fabrication techniques that will produce a durable limb. I start with a good cast from a previous prosthesis to begin the fabrication process. A tight fit is important because any air pockets inside the socket will increase buoyancy. I prefer to use some type of liner inside the socket. This is not essential and is left purely up to the preference of the amputee, but a liner of Pelite or flexible thermoplastic will increase comfort, especially when ambulating in sand or surf. Once the liner is made, I laminate the socket using nylon and carbon graphite impregnated with an acrylic resin.

After trying numerous feet in this application I have chosen the SAFE II foot as the optimal shower/swim foot. Foresee (manufacturer of the SAFE foot) also makes a waterproof version of the foot but I have found that the Delran keel tends to separate from the foam sooner than the wooden keel disintegrates from water exposure. Therefore I generally will use a heavy duty SAFE II foot and seal the wooden keel with resin. I plug the bolt hole with silicone to prevent water from entering from the foot. I have also used a hot knife to create a grid pattern on the bottom of the foot for added traction. A titanium foot bolt is indicated since it is far more rust resistant.

Initially, I set up the socket on an endoskeletal alignable system in order to be able to make adjustments. I walk the amputee and correct alignment as usual. When I have a proper barefoot gait and comfortable standing alignment I take the prosthesis for finishing. Next I use the vertical transfer jig to duplicate my alignment and a Foresee graphite ankle block replaces my alignable components. I use rigid foam to bridge between the socket and the ankle block. When this is set, I remove the leg from the vertical transfer jig and shape the foam into a conical configuration tapering to the ankle block. The foam is sealed with resin and a final lamination of double carbon weave spaced between a double fiberglass creates a strong and durable finish. I often utilize some type of wild personal fabric for the outer layer of lamination using a non-pigmented resin.

When the prosthesis is trimmed and sanded I apply the foot and use silicone or some type of sealant beneath the Foresee ankle block. I score the foot and seal the bolt hole. The last component is the suspension sleeve. Something has to hold the limb onto the amputee and with the durability of today's suspension sleeves they provide not only good suspension but if it is fitted properly the sleeve will keep the residual limb dry. I have found that suspension sleeves do have a limit as to how dry they will keep the limb. When the amputee dives into the water, the pressure against the upper edge of the sleeve can force water beneath the sleeve and into the socket. This can also occur when diving to depths below thirty feet.

There are some variations on this prosthesis that can add new dimensions to the life of amputees. The most common variation is a swim/walk ankle. Two manufacturers make a version of this component. One is made by Rampro and has a watertight feature that allows the ankle to be positioned for walking and totally pronated for swimming. A round key can be turned on the side of the ankle to allow the foot to be repositioned. I recommend putting the key on the medial side for easier access. The other mechanism is made from aluminum and has no cover. I used one for several years but the aluminum did not hold up and soon created considerable play in the mechanism. It drove me crazy to walk on the device. I recommend the Rampro swim/walk ankle. I have also used a SAFE Symes foot so that the foot stays straighter when in total plantar flexion. Another foot I have used is the Kingsley Wayfarer foot but I did not like the weight or action.

A second variation is to put a more cosmetic cover on the limb. Remember that you can't create something that will trap air or else the leg will tend to float. Several manufacturers make a shaped close celled foam cover that can be glued onto the leg. Make sure that if it is sealed up on both ends that you create holes for the water to flow through the leg. I recommend holes on the posterior side, behind the knee then again down at the base of the ankle.

The shower/swim prosthesis can be a huge lifestyle enhancement for the amputee. Having the capability to use a prosthesis in water applications such as shower, tub, pool, beach, or boating opens the amputee's world. The resulting savings to the amputee over the long run is substantial. Every prosthetist has seen the result of an amputee using their regular prosthesis in the water and knows that moisture exposure drastically shortens the life expectancy of a prosthesis. It makes economic sense to invest in a specific leg for water activities. Only the VA has specific guidelines and provisions for a water prosthesis and most insurers will not cover these costs. In my private practice, I will offer the shower/swim prosthesis at a substantial discount since the components are inexpensive and I already have the cast.

When asked by third party payees as to why an amputee needs a second prosthesis I ask them to consider this. Do you only have one pair of shoes? Can you safely accomplish all of your activities of daily living or recreation with a single set of shoes? This allows a non-amputee to relate to the dilemma of wearing a prosthesis. In conclusion, the shower/swim prosthesis can give the amputee the confidence and ability to enjoy an expanded lifestyle.