Mechanical Engineering ETDs

Publication Date

11-17-2008

Abstract

This study compares the pattern of failure of locking compression plates (LCP) and intramedullary nails (IM) used in treatment of unstable comminuted distal femur fractures in osteoporotic and normal bones. Possible late failure of the fixation represents a critical problem in the treatment of distal femur fractures. Few biomechanical studies have examined the effects of osteoporosis on stability of the bone after fixation. Some reports have described catastrophic failure of fixation when LCP were used compared with IM nails making salvage procedures difficult. This thesis reports on the behavior of synthetic composite bone and embalmed cadaveric bone with and without osteoporosis, fixed with LCP or IM nails and subjected to axial, shear and bending stresses. We also present a finite element (FE) model simulating the mechanical behavior of bones with distal femur fractures after fixation with LCP and IM nail. The proposed model is validated using experimental data. The FE model can be used to explain the reason for failure of the distal femur fracture fixation by comparing the max stresses generated in the femur under combined loading conditions to the femur strength. Both experimental and numerical methods proved that distal femur fixation with LCP is more prone to damage propagation and sudden failure compared with IM fixation.

Degree Name

Mechanical Engineering

Level of Degree

Masters

Department Name

Mechanical Engineering

First Committee Member (Chair)

Mahmoud Reda Taha

Second Committee Member

Thomas DeCoster

Third Committee Member

Yu-Lin Shen

Sponsors

Stryker Orthopaedics, the University of New Mexico Department of Orthopaedics

Document Type

Thesis

Language

English

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