Effects of Unity Prosthetic Elevated Vacuum Suspension System on Minimum Swing Toe Clearance

Abstract

BACKGROUND: The risk of tripping in people with amputation is greater than that of able-bodied individuals due to reduced toe clearance during the swing phase. Appropriate prosthetic suspension may increase toe clearance by providing more secured attachment between the residual limb and prosthetic socket. Research is lacking on the Unity suspension system's effect on swing toe clearance. METHODS: Twelve people with transtibial amputation were fitted with the Unity suspension system. After one month accommodation period, the person walked with active (ON) or inactive vacuum (OFF) in a CAREN-Extended virtual reality system, across multiple simulated real-world scenarios. Prosthetics minimum swing toe clearance, and kinematic data, while the vacuum was ON or OFF, were compared with the intact side and a group of 12 able-bodied individuals. RESULTS: Minimum swing toe clearance (MSTC) and knee flexion angle were larger on the prosthetic side (active and inactive vacuum) compared to both the intact side and the control group. However, hip flexion angle on the prosthetic side was approximately 17% smaller than the control group. Unlike the control group, MSTC with active and inactive vacuum suspension was not significantly different between level walking and other walking conditions. Finally, among all walking conditions, the lowest swing toe clearance for both control and the amputee groups was recorded when the limb was at the top of a side-slope. CONCLUSION: An effective suspension system could improve toe clearance; however, significant differences were not found between active and inactive vacuum conditions. The likelihood of inappropriate foot contact on side-slope ground might be greater than other walking conditions for both able-bodied and amputee groups, possibly leading to stumbling or falling. Layman's Abstract Walking over non-level surfaces are more challenging than level walking, especially for people with below the knee amputation. Moreover, due to reduced toe clearance during the gait, people with amputation have higher risk of tripping and falling than able-bodied individuals. The purpose of this study was to evaluate the effects of a prosthetic suspension system, a critical component that connects the residual limb to the prosthesis, on toe clearance during gait across multiple simulated real-world walking scenarios. Twelve people with below the knee amputation and a group of 12 able-bodied individuals participated in this study. The results of this study showed that an effective suspension system could improve toe clearance during swing phase. The likelihood of inappropriate foot contact on side-slope ground might be greater than other walking conditions for both able-bodied and amputee group, possibly leading to stumbling or falling. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/36847/28624 How To Cite: Gholizadeh H, Lemaire E.D, Nantel J. Effects of unity prosthetic elevated vacuum suspension system on minimum swing toe clearance. Canadian Prosthetics & Orthotics Journal. 2022; Volume 5, Issue 1, No.1. https://doi.org/10.33137/cpoj.v5i1.36847 Corresponding Author: Julie Nantel, PhD School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada, K1N 6N5E-Mail: jnantel@uottawa.caORCID ID: https://orcid.org/0000-0001-7253-9222