Parametric analysis using the finite element method to investigate prosthetic interface stresses for persons with...

Area of Science:

• Biomechanics
• Biomedical Engineering
• Prosthetics and Orthotics

Background:

• Finite element (FE) modeling is crucial for understanding biomechanical interactions.
• Residual limb-prosthetic socket interface stress influences prosthetic effectiveness and user comfort.
• Previous models often lacked detailed analysis of parametric variations.

Purpose of the Study:

• To investigate how variations in prosthetic socket design and residual limb geometry affect interface stress distribution.
• To quantify the sensitivity of interface stresses to specific design and geometric parameters.
• To provide data for optimizing prosthetic socket design for below-knee amputees.

Main Methods:

• Development of a scaled finite element (FE) model of a below-knee residual limb and prosthetic socket.
• Parametric analyses to assess the impact of socket stiffness, liner properties, rectification, and limb geometry.
• Sensitivity analysis to illustrate behavioral trends and identify critical parameters.

Main Results:

• Interface pressures are highly sensitive to prosthetic rectification and soft tissue shape/bulk.
• Socket stiffness has minimal effect on liner interface pressures.
• Prosthetic liner stiffness influences stress distribution, with rectification affecting shear stress.
• Residual limb length and soft tissue compliance significantly alter interface pressure distribution.

Conclusions:

• Both prosthetic design choices and residual limb geometry are critical determinants of interface stress.
• Optimizing socket rectification and accounting for soft tissue characteristics are essential for improved prosthetic fit.
• FE modeling provides valuable insights into complex biomechanical interactions at the residual limb-socket interface.