Ergonomic evaluation of low-cost prosthetic products: comparison between rigid and flexible ankle joint design

Abstract

Disability due to an amputated leg affect people in Indonesia, including those with low to middle income categories. To facilitate them, Yayasan Difabel Mandiri manufactures a low-cost flexible ankle prosthetic to fix the shortcomings of the rigid ankle prosthetics available in the market. This experimental study aimed to evaluate the use of flexible ankle prosthetic for daily activities. Seven disabled people simulated a walking task with or without a backpack loaded with 10% of body mass using two prosthetic types (i.e., flexible and rigid ankle). Measures were obtained to evaluate the performance of the prosthetic including the center of pressure (COP) indicating static and dynamic stability and subjective ratings of prosthetic evaluation questionnaire (PEQ). Results showed a significant difference in dynamic stability between the rigid and flexible ankle prosthetic foot with a better performance indicated by the flexible ankle joint design. No differences were shown for the use of backpack. Flexible ankle further improves the quality of life of disabled people specified by 12.76% higher average rating of PEQ. In conclusion, flexible ankle joint potentially improves the design of the prosthetic foot to meet the need and comfort of disables.