Thermoplastic alignment couplings for prostheses

In the context of modern engineering practice, this paper describes the exploitation of thermoplastic materials for the provision of lightweight, low cost, corrosion free, alignment devices for lower limb prostheses. After setting out design requirements, four newly developed devices are described and discussed. These are respectively a four jack system, a serrated wedge system, a spherical alignment system and a serrated slider. The level of laboratory fatigue testing and experimental field performance is reported and examples are shown of the application of these systems to tapered column thermoplastic below-knee prostheses.