Appropriate compression values for the transtibial prosthesis using the AERO prosthetic liner

Abstract

Positive model rectification is a key factor in providing a comfortable and successful transtibial prosthetic socket fitting. This study aimed to assess whether a 4% compression value in 3- and 5-mm thickness affordable ethylene-vinyl acetate roll-on (AERO) liners yields acceptable comfort and pressure distribution for transtibial prosthetic users. Stump socks were used to adjust volume in the fitting process with a socket compressed to 4%, and pressure data were collected using 6 force-sensing resistor (FSR400) sensors placed in areas sensitive and tolerant to pressure. Peak pressure was collected from 40 steps, and pressure uniformity was calculated using the coefficient of variation in 2-min walking on the treadmill. The socket comfort score was collected after the trial. Appropriate compression values, pressure distribution, and socket comfort score were analyzed using Wilcoxon signed-rank tests, and effect size was determined using Cliff’s delta. The study found that a 4.95% compression was optimal for a 3-mm thickness liner, whereas a 4.5% compression suited a 5-mm liner better for comfort. Moreover, the study observed a small similarity in pressure distribution between liners, as indicated by Cliff’s delta, with the 5-mm liner possibly providing more even pressure because of its thickness. Despite being made of the same material, liners with different thicknesses distribute pressure differently. Therefore, this study suggests that a 4% universal compression value in the affordable ethylene-vinyl acetate roll-on liner may be effective for use in a clinical setting. Future studies should include more participants to identify the appropriate compression for a variety of residual limbs.