Abstract
To function effectively, a lower limb prosthetic socket must remain securely coupled to the residual limb during walking, running and other activities of daily living; this coupling is referred to as suspension. When this coupling is insufficient longitudinal pistoning of the socket relative to the residual limb occurs. Increasing friction of the socket/liner interface may improve socket suspension and textured sockets may be fabricated relatively easily with 3D printing. The aim of this study was to investigate longitudinal displacement of sockets with different types of textures under two suspension conditions: passive suction and active vacuum. In order to do this, we developed a mock residual limb and mechanical testing protocol. Prosthetic sockets, 14 textured sockets and an Original Squirt-Shape (OSS) Socket, were fabricated from polypropylene copolymer using the Squirt-Shape™ 3D Printer and compared to a smooth socket thermoformed from polypropylene copolymer. Sockets were mounted onto a dual durometer mock residual limb and subjected to four levels of distraction forces (100 N, 250 N, 500 N and 650 N) using a hydraulic material testing system. There was a statistically significant three-way interaction between suspension, force level and texture (p < 0.0005). Longitudinal displacements between textured and reference sockets, for all force levels and both suspension conditions, were significantly different (p < 0.0005). Using these newly developed mechanical testing protocols, it was demonstrated that texturing of polypropylene copolymer sockets fabricated using Squirt-Shape significantly decreased longitudinal displacements compared to a smooth socket. However, none of the novel textured sockets significantly reduced longitudinal displacement compared to the OSS socket under passive suction suspension.
| Original language | English (US) |
|---|---|
| Article number | e0237841 |
| Journal | PloS one |
| Volume | 15 |
| Issue number | 8 August |
| DOIs | |
| State | Published - Aug 2020 |
Funding
This work was supported by the Office of the Assistant Secretary for Health Affairs, through the Neuromusculoskeletal Injuries Research Award under Award No. W81XWH-16-1-0485 to SF. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the Department of Defense (DOD). Prosthetic Design Inc. were funded by the DOD as a collaborative partner on this study. As a collaborative partner they provided support in the form of research materials (primarily printing of sockets). Additional roles in this study included developing the texture patterns, validating 3D printing processes, and contributing to preparation of the manuscript. The DOD award provided support in the form of salaries for most of the authors [SF, BP, JY, VS], but the funder did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Author JQ was supported on a training grant from National Institute on Disability, Independent Living and Rehabilitation Research of the U.S. Department of Health and Human Services, Administration for Community Living, grants 90AR5010 and 90AR5031. Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the U.S. Department of Health and Human Services. The specific roles of all authors are articulated in the ‘author contributions’ section.
ASJC Scopus subject areas
- General Agricultural and Biological Sciences
- General
- General Biochemistry, Genetics and Molecular Biology