Passive prostheses

The cosmetic prosthesis is also known as passive prosthesis is the oldest prototype, with the first making as an artificial hand made from Marcus Sergius in the Punic War (218-201 BC). This device is made by skilled army and emerged as a gauntleted hand, or armored glove (Julio, 2007). Although the representation of human hand is exists, the static device causes the absence in the movement of hand and thereby promotes the uncomfortable feelings of the prosthesis user. 

Finger joint replacements are divided into three types (1) hinge, (2) polycentric, and (c) space-fiUer. The most widely used are the space-filler type. These are made of high performance silicone rubber (polydimethylsiloxane) and are stabilized with a passive fixation method. This method depends on the development of a thin, fibrous membrane between implant and bone, which allows pistoning of the prosthesis. This fixation can provide only minimal rigidity of the joint [Swanson, 1973). Implant wear and cold flow associated with erosive cystic changes of adjacent bone have been reported with silicone implants [Carteret al., 1986 MaistrelU, 1994]. 

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. 

Generally, there are two types of prosthetic hand namely active and passive hand. The passive hand is usually used as cosmetic and it does not have any sensors and electronic processing. This kind of prosthesis is suitable for the one who prefer aesthetically pleasing prosthesis or one who do not having an active lifestyle. On the other hand, active prosthesis stressed more on the functional part which involved all the processors and sensors example of this type is CyberHand and Utah/MIT hand [1]. 

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