COMMON FITTING TECHNIQUES:

The most common procedure for fitting a prosthesis involves creating a plaster replica of the stump which is then used to size the prosthesis.  A series of manual modifications, called rectification, soon follows.  In this process, the prosthetist rectifies the plaster mold by removing areas where the the patient wants more pressure applied and adding areas where the patient wants pressure relief (Independent Living Magazine).  This process is not only extremely time consuming and expensive, but it also allows for a large margin of error because it depends entirely on the craftsmanship of the prosthetist.  Even if the prosthetist is especially skilled, "with just a rock-hard cast, it is impossible to address the shape changes of bone and tissue that occur while an amputee walks with the prosthesis" (USA Today Magazine).  As a patient walks, the residual limb changes and molds to the prosthesis, and the pressure points vary as the body shifts its weight.  This is very difficult to replicate from looking at a solid plaster cast.         

THE LATEST IN STUMP FITTING:

Stump fitting has improved dramatically in last few years.  Instead of creating plaster casts, prosthetists are now able to use three-dimensional imaging techniques to actually measure shape change while the patient is wearing a prosthetic device.  This process, known as spiral computed tomography (CT), yields x-rays that display soft-tissues clearly on a cross-sectional image.  According to Michael Vannier, head of the department of radiology, University of Iowa, this new process means that "not only is it possible to make better measurements, but the measurements show real change that occurs within the stump.  The stump is changing shape as the amputee walks, and we now possess a method that will accurately translate those changes into quality fit for prosthetics."  This technique is much faster than the plaster technique (taking only 30 seconds to make a scan), and it is much easier to perform and less painful for the patient (USA Today Magazine).

Below:  The most commonly used process for  fitting the stump for a prosthesis.  Photos courtesy of Independent Living Magazine 

   Step One: measuring the stump

Step Two:  casting a plaster replica of the stump 

Step 3: using the plaster replica to create a prosthesis through the process of rectification.

Above: The newest technology in fitting for artificial limbs: 3-D imaging techniques.  Here an amputee lies in a spiral computed tomography scanner that will determine quality of fit of his prosthesis in its socket.  Proper fit will reduce pain and difficulty in walking and or standing.  Photo from USA Today Magazine

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