The role of human thermoregulation in thermal discomfort in lower-limb prosthetics: A scoping review.

Background: Thermal discomfort is one of the most prevalent issues experienced by lower-limb prosthetic users where, on average, 54% of users report thermal-related issues. This arises from wearing a prosthetic socket, which may disrupt the thermoregulatory system due to the low thermal conductivity of materials used in prosthetic sockets and liners. Despite the reported prevalence, there is little understanding of the impact of wearing a prosthesis on the body's thermoregulatory system and how users perceive thermal discomfort.

Objectives: This review aimed to evaluate the current understanding of how human thermoregulation correlates with subjective measures of thermal discomfort among lower-limb prosthetic users. It sought to gain a deeper understanding of how thermoregulatory parameters compare and relate to the subjective experience of thermal discomfort in this population.

Methodology: The study design followed a scoping review structure to identify gaps in knowledge on the topic. A literature search was conducted across five online databases: Medline (ProQuest), EMBASE, Cochrane, CINAHL and PsycINFO. The searches covered literature from the earliest available date in each database up until February 2024. A search strategy was created to identify the relevant literature. An inclusion/exclusion criterion was then applied to identify studies that only measured either physiological or psychological aspects of thermoregulation and compared these aspects to thermal discomfort/comfort feedback. The QualSyst critical appraisal tool was used to gain quality score for each included article.

Findings: 8 articles were identified for inclusion in this review, confirming a dearth in research into how wearing a prosthesis affects thermoregulation at the body/device interface (BDI) and the perception of thermal discomfort. Furthermore, it raised question to the relevance of using residual limb skin temperature measurements to assess thermal discomfort in lower-limb prosthetics. Perspiration at the BDI emerged as a potentially significant contributor to thermal discomfort, a consensus reflected in the literature.

Conclusion: Despite significant technological advancements, thermal discomfort remains a persistent issue. Therefore, further research is warranted to further understand how wearing a prosthesis affects the thermoregulatory system, enabling the development of innovative components which can mitigate thermal discomfort and in turn improve the quality of life of lower-limb prosthetic users.