USING A SWEATING RESIDUUM/SOCKET INTERFACE SIMULATOR FOR THE EVALUATION OF SWEAT MANAGEMENT LINERS IN LOWER LIMB PROSTHETICS
Authors: McGrath Michael , Davies KC , Gallego Ana , Laszczak Piotr , Tang Jinghua , Zahedi Saeed , Moser David 
Published: March 2021

BACKGROUND: Lab-based simulators can help to reduce variability in prosthetics research. However, they have not yet been used to investigate the effects of sweating at the residuum-liner interface. This work sought to create and validate a simulator to replicate the mechanics of residual limb perspiration. The developed apparatus was used to assess the effects of perspiration and different liner designs.

METHODOLOGY: By scanning a cast, an artificial residuum was manufactured using a 3D-printed, transtibial bone model encased in silicone, moulded with pores. The pores allowed water to emit from the residuum surface, simulating sweating. Dry and sweating cyclic tests were performed by applying compressive and tensile loading, while measuring the displacement of the residuum relative to the socket. Tests were conducted using standard and perforated liners.

FINDINGS: Although maximum displacement varied between test setups, its variance was low (coefficient of variation <1%) and consistent between dry tests. For unperforated liners, sweating increased the standard deviation of maximum displacement approximately threefold (0.04mm v 0.12mm, p<0.001). However, with the perforated liner, sweating had little effect on standard deviation compared to dry tests (0.04mm v 0.04mm, p=0.497).

CONCLUSIONS: The test apparatus was effective at simulating the effect of perspiration at the residual limb. Moisture at the skin-liner interface can lead to inconsistent mechanics. Perforated liners help to remove sweat from the skin-liner interface, thereby mitigating these effects.

Layman’s Abstract

Simulators can be used in prosthetics research to make experiments more repeatable. In this study, a test apparatus was created to replicate the mechanical effects of residual limb sweating. An artificial residual limb was made from silicone and a 3D printed, transtibial bone model. Small holes were made throughout the silicone to act like pores, allowing water to travel to the outside surface, like sweat. The limb was loaded to mimic walking and its movement within the socket was measured. For some tests, water was added internally to see the effect of sweat. Two types of liner were used and compared; a standard one and one with perforations. In terms of movement, the results were generally consistent between each cycle for the dry tests. For standard liners, the addition of sweating increased the variability of movement approximately threefold (0.04mm v 0.12mm, p<0.001). However, with the perforated liner, sweating had little effect on movement (0.04mm v 0.04mm, p=0.497). The test apparatus simulated the effect of residual limb sweating. The findings indicate that moisture on the skin can lead to inconsistent movement, but perforated liners help to remove this moisture, which helps improve consistency of performance.

Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/35213/27472

How To Cite: McGrath M, Davies K.C, Gallego A, Laszczak P, Tang J, Zahedi S, Moser D. Using a sweating residuum/socket interface simulator for the evaluation of sweat management liners in lower limb prosthetics. Canadian Prosthetics & Orthotics Journal. 2021;Volume 4, Issue 1, No.3. https://doi.org/10.33137/cpoj.v4i1.35213

Corresponding Author: Dr. Michael McGrath, PhDResearch Scientist–Clinical Evidence,Blatchford Group, Unit D Antura, Bond Close, Basingstoke, RG24 8PZ, United Kingdom.Email: mike.mcgrath@blatchford.co.ukORCID: https://orcid.org/0000-0003-0195-970X