A pin-array method for capturing tissue deformation under defined pressure distributions and its application to...

Area of Science:

• Biomedical Engineering
• Prosthetics and Orthotics
• Biomechanics

Background:

• Developing countries require affordable and effective upper limb prosthetics.
• Current prosthetic socket design often lacks patient-specific interface optimization.
• Open-frame trans-radial socket designs offer potential for LMIC deployment.

Purpose of the Study:

• To introduce a mechanical tool for designing prosthetic socket pad shapes.
• To investigate the relationship between pressure distribution, tissue displacement, and interface loading.
• To assess the tool's utility in optimizing prosthetic fit for lower- and middle-income countries (LMICs).

Main Methods:

• A pin-array mechanical tool was developed to apply controlled pressure distributions to tissue.
• Tissue displacement was captured by fixing the pin positions after pressure application.
• Three studies were conducted on a single subject to validate the tool's functionality and findings.

Main Results:

• Surface stiffness showed an inverse relationship with array size.
• Duplicate pad shapes generated similar loads, but results were sensitive to muscle activation.
• Different forearm areas exhibited varying tissue displacements under identical pressure distributions.

Conclusions:

• The pin-array tool shows promise for prosthetic pad design, particularly for LMIC applications.
• The approach can inform the development of more practical prosthetic devices and other skin-interfacing technologies.
• Further development could enable clinical applications and data generation for finite element modeling and sensor assessment.