Economics of modular prostheses/1

Some clarification is needed about the meaning of "modular" in prosthetics. To describe the endoskeletal modular prosthesis as simply "modular" is not fully correct. The crustacean (wood) exoskeletal array used for many years in above-knee limb construction was modular, at least in the assembly process. For this, a fitter or his technician took a knee-shank set-up, a footankle set-up, and a socket and assembled these in a modular fashion. Each of the major elements was in fact a module. Nevertheless, the value of modularity was lost whenever replacement of individual components was required; it was quite difficult to replace a major component such as the knee-shank set-up in this system without re-making the whole prosthesis. The nature of the design, in wood finished with plastic laminates, prevented easy replacement. Thus a particular significance to the modularity of current endoskeleral designs is associated with the quickness with which individual components might be replaced. This "plug-out, plug-in" capability simplifies servicing and maintenance of prostheses requiring either changes in function or replacement due to wear or failure.