Analysis of forces and stresses incurred in the joints of the hand and development of a magnetic composite for use in finger joint replacements

Kent D Butz, Purdue University

Abstract

The purpose of the present study was to investigate the joint forces and stress distributions at the metacarpophalangeal joint of the hand, and to develop a magnetic composite material aimed at reducing wear rates in finger joint replacements. Prior to this work, little has been done to characterize the stresses and stress distributions incurred at the finger joints. A number of common activities were investigated using biomechanical analysis techniques to determine typical muscle and joint contact forces experienced in the hand. The metacarpophalangeal joint, the most commonly replaced finger joint, was then modeled using two- and three-dimensional COMSOL-based finite element analyses. Among the findings was that the inner structure of the phalanges, and material properties of cancellous bone play an important role in stresses developed at the joint surfaces. In addition, a composite material was developed utilizing magnetized particles integrated into an ultra-high molecular weight polyethylene base. By introducing a magnetic repulsion force between the joint bearing surfaces, a net reduction in joint contact forces, and thus a reduction in joint wear, may be seen. A sustained magnetic field was induced on a composite with stainless steel 410 particles as proof of concept, and finite element models of the composite with particulate of the magnetically strong neodymium iron boron demonstrate the potential to significantly reduce contact forces at the joints.

Degree

M.S.M.E.

Advisors

Nauman, Purdue University.

Subject Area

Biomedical engineering|Mechanical engineering|Biomechanics

COinS