First-Order Model for the Analysis of Stump Stresses for Below-Knee Amputees

Abstract

This study extends what had been a purely numerical model that used influence-factor matrices to relate the stump stresses to prosthesis loads for unilateral, below/knee amputees. Previously published influence-factor matrices are now factored into a coefficient matrix times the inverse of a stump geometry matrix. Using actual stump parameters, new information is learned about how the resistive moment of the stump balances the flexion-extension moment of the prosthesis and why certain normal stresses reach a maximum during a specific portion of the stance phase of the prosthesis.