Prosthetic fit

The basic configuration of Bowden cables in prostheses has changed little over the intervening years and is stiU in use today. In fact, if prehensile function is the primary goal of the prosthetic fitting, the device of choice for most persons with amputations is a body-powered, Bowden-cable-operated prosthesis with a split hook-shaped terminal device. This is in spite of all the technological advances in electronics, computers, and dc motor technology that have occurred since the end of World War H. 

In the past, a prosthetic fitting was deemed to have been unsuccessful if the patient did not wear an actively controlled prosthesis for prehensile function. In a recent study, Fraser (1998) showed that amputees used their prostheses most frequently for nonprehensile tasks, such as stabilizing, pushing, or pulling an object. In addition, Fraser (1998) showed that amputees with passive or cosmetic prostheses used their devices for nonprehensile tasks on average just as frequently as amputees with active prostheses. These results show that just because a prosthetic device is passive or cosmetic does not imply that it is not functional. 

The dimensions of the residual limb vary with time (Fig. 33.5). The decrease in stump size results from the reduction of edema, wasting of soft tissues from prosthetic stresses, disuse atrophy of the residual limb musculature, and decrease in fatty tissue with overall weight loss. Initial prosthetic fitting often begins 1 to 2 weeks after surgery, following early compression wrapping. The time... 

The prosthetist also evaluates prosthetic fit, or the comfort (pressure distribution), stability, suspension, aligiunent, and function of the prosthesis. The fitting of a prosthesis is an empirical process. The prosthetist has no quantitative information regarding the load distribution of the soft tissues and... 

As alluded to earlier, knowledge of the interface stress distribution between the residual limb and the prosthetic socket enables objective evaluation of prosthetic fit. It is this desire for quantitative description of the prosthetic interface stress distributitHi that has motivated many experimental and numerical investigations of prosthetic interface stress. 

The repeatability test indicated an acceptable repeatibility. An improved device can possibly be a useful tool in prosthetic fitting and CAD socket design. 

Newton R, D. Morgan, M Schreiber. (1988) Radiological evaluation of prosthetic fit in below-the-knee amputees. Skeletal Radiol 17(4) p. 

Prosthetic fitting has been said to be correlated with pistoning [1, 2]. Thus, measuring the pistoning would be helpful in determining the optimal prosthetic fit. 

Yigiter K, Sener G, Bayar K (2002) Comparison of the effects of patellar tendon bearing and total surface bearing sockets on prosthetic fitting and rehabilitation. Prosthet Orthot Int 26(3) 206-212... 

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