Analysis of Pressure Distribution in Transfemoral Prosthetic Socket for Prefabrication Evaluation via the Finite Element Method

Abstract

In this study, we estimated and validated the pressure distribution profile between the residuum and two types of prosthetic sockets for transfemoral amputees by utilizing a finite element analysis. Correct shaping of the socket for an appropriate load distribution is a critical process in the design of lower-limb prosthesis sockets. The pressure distribution profile provides an understanding of the relationship between the socket design and the level of subject comfortability. Estimating the pressure profile is important, as it helps improve the prosthesis through an evaluation of the socket design before it undergoes the fabrication process. This study focused on utilizing a magnetic resonance imaging (MRI)-based three-dimensional (3D) model inside a predetermined finite element simulation. The simulation was predetermined by mimicking the actual socket-fitting environment. The results showed that the potential MRI-based 3D model simulation could be used as an estimation tool for a pressure distribution profile due to the high correlation coefficient value (R 2 > 0.8) calculated when the pressure profiles were compared to the experiment data. The simulation also showed that the pressure distribution in the proximal area was higher (~30%) than in the distal area of the prosthetic socket for every subject. The results of this study will be of tremendous interest for fabricators through the use of a finite element model as an alternative method for the prefabrication and evaluation of prosthetic sockets. In future prosthetic socket fabrications, less intervention will be required in the development of a socket, and the participation of the subject in the socket-fitting session will not be necessary. The results suggest that this study will contribute to expanding the development of an overall prefabrication evaluation system to allow healthcare providers and engineers to simulate the fit and comfort of transfemoral prosthetics.

Seeing the Big Picture: Improving The Prosthetic Design Cycle Using 360° 3D Digital Image Correlation

“…Simulations of prosthetic sockets begin with obtaining a sample geometry. The most common approach utilizes magnetic resonance imaging (MRI) scans to obtain the hard and soft tissue geometry of a residual limb for simulations [7][8][9][10]. Material properties in these simulations are commonly simplified to homogeneous isotropic linear elastic behavior.…”

“…Material properties in these simulations are commonly simplified to homogeneous isotropic linear elastic behavior. More sophisticated models utilize hyperelastic or viscoelastic formulations of material behavior [6,7]. Loading and boundary conditions vary considerably based on the phase of the gait cycle.…”

“…The magnitude of stresses simulated was most commonly 800 N which is approximately 110% of an ideal patient's body weight [14][15][16]. In almost all cases of multibody simulations, the interface between the limb and socket was represented by a coefficient of friction (typically of value 0.5) [6,7].…”

Seeing the Big Picture: Improving The Prosthetic Design Cycle Using 360° 3D Digital Image Correlation

“…The magnitude of stresses simulated was most commonly 800 N which is approximately 110% of an ideal patient's body weight [14][15][16]. In almost all cases of multibody simulations, the interface between the limb and socket was represented by a coefficient of friction (typically of value 0.5) [6,7].…”

Thermo-mechanical and degradation properties of naturally derived biocomposites for prosthesis applications: Analysis of the interface pressure and stress distribution on the developed socket

“…In conjunction with this, several studies have been conducted analytically and numerically using the finite element method (FEM) to examine equivalent stress, contact pressure, contact angle and bidirectional deformation on socket interfaces. [31][32][33] However, these analyses provided alternate estimation for the prefabrication of a prosthetic socket but, due to the geometrical variations of the residual limb, the stress generation, pressure distribution and thermal stress between residual limb and socket are not the same at every section. 34,35 Therefore, this study focus to develop naturally derived laminated biocomposites for the knee prosthetic socket application.…”