Comparative analysis of below-knee prosthetic socket liner materials.

Four materials used in lining prosthetic sockets were compared for their potential usefulness in below-knee applications. Tests carried out included determinations of resistance to compression, resistance to flexural abrasion and coefficients (static and dynamic) of friction. These tests were designed, respectively, to assess changes occurring during end-use brought about by extensive application of compressive or shear force, and to predict the ability to retain contact with the body and socket. Of the four materials in the study (Bock-Lite, Pedilin, polyurethane and silicone), Bock-Lite and silicone had high compression resistance, Bock-Lite had good resistance to flexural abrasion, and polyurethane and silicone had high coefficients of frictional resistance. Thus, Bock-Lite will be the most durable of the four materials but, since it had the lowest frictional coefficient, it may slip in use. Conversely, silicone and polyurethane, which will be retained in position more easily, are easily torn or compressed, so are likely to need replacement more frequently.