Assessing Phase-Change Materials as Effective Long-Term Biosensors in Limb Prosthetics

Monitoring and controlling the microclimate at the skin–socket interface of limb prostheses is an important, yet unresolved, clinical problem. Phase-change materials (PCMs) represent a promising biosensor technology that holds the potential to both detect and alter (i.e., stabilize) changes in the temperature of a hybrid biological/mechanical system, such as a prosthesis. The biologically inspired sensor capabilities of PCMs can enhance the internal socket conditions and offer improved comfort and suspension while minimizing skin injuries for prosthesis users. This study investigated how prosthetic liners equipped with PCM biosensors affected the long-term outcomes for prosthesis users. In this double-blinded longitudinal crossover study, a cohort of transtibial prosthesis users wore regular conventional liners for six months and PCM liners for another six months. Prosthesis utilization, physical performance, and gait symmetry were studied using Modus StepWatch, the 2-minute walk test, and the TekScan F-Scan gait test, respectively. Measured parameters from these various tests, acquired at multiple timepoints during the study, were compared pairwise between the two liners per individual. While the obtained quantitative data trends, such as the gait symmetry, favored the PCM liners, no statistically significant differences were found between the PCM and conventional gel liners in any of the study parameters.