Symes prostheses have been developed for amputations at the ankle, where the stump is usually very large and rounded, making suspension much easier to design for. Following an ankle disarticulate amputation, the end of the stump can take a lot more load than a usual transtibial amputation stump. However it is still necessary to shape the upper part of the socket in order that a considerable share of the load can be taken by the knee while standing or while walking. The prosthesis usually incorporates an Alpha Design Liner, which is designed with the help of a Tracer CAD System, the latest technology available. The prostheses are usually made with a window at the back to enable the rounded end of the stump to pass through and into the prosthesis.
An example of a Symes amputee is Professor Pretorius. As can be seen in the accompanying photographs, her residual limb is exceedingly atrophied, having a very thin and bony stump with a pronounced bulbous end (see picture 2). With the assistance of modern technology we were able to design and manufacture a custom silicone liner for her leg (see picture 1). We accomplished this by taking a cast of her residual limb. This was sent to a company, which made a silicone liner, and for which we manufactured the prosthesis (see picture 3).
Professor Pretorius walked and tested the socket over an eight week trial period, during which time we were able to fine tune the prosthesis. Because of the bony protrusions on the residual limb this had to be carried out extremely accurately in order for the prosthesis to be as comfortable as possible.
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