Specimen-Specific Finite Element Models for Predicting Fretting Wear in Total Hip Arthroplasty Tapers.

Products from fretting wear and corrosion in the taper junction of total hip arthroplasty (THA) devices can lead to adverse local tissue reactions. Predicting damage as a function of design parameters would aid in the development of more robust devices. The objectives of this study were to develop an automated method for identifying areas of fretting wear on THA taper junctions, and to assess the predictive ability of a finite element model to simulate fretting wear in THA taper junctions.

Prediction of contact mechanics in metal-on-metal Total Hip Replacement for parametrically comprehensive designs and loads.

Manufacturers and investigators of Total Hip Replacement (THR) bearings require tools to predict the contact mechanics resulting from diverse design and loading parameters. This study provides contact mechanics solutions for metal-on-metal (MoM) bearings that encompass the current design space and could aid pre-clinical design optimization and evaluation. Stochastic finite element (FE) simulation was used to calculate the head-on-cup contact mechanics for five thousand combinations of design and loading parameters.

Total hip arthroplasty head-neck contact mechanics: a stochastic investigation of key parameters.

A variety of design and patient parameters have been implicated in recent reports of fretting corrosion at modular connections in total hip arthroplasty. We sought to identify the relative sensitivity of mechanical fretting to a comprehensive set of parameters such that attention may be focused on key variables. Stochastic finite element simulation of the head-neck taper-trunnion junction was performed.

Algorithms for a strain-based plasticity criterion for bone.

A range of stress-based plasticity criteria have been employed in the finite element analysis of the post-elastic behaviour of bone. There is some recognition now that strain-based criteria are more suitable for this material because they better represent its behaviour. Moreover, because bone yields at relatively isotropic strains, a strain-based criterion requires fewer material parameters unlike those required for a stress-based criterion.

Bone properties affect loosening of half-pin external fixators at the pin-bone interface.

Introduction: Local bone yielding at the pin-bone interface of external fixation half-pins has been known to initiate fixator loosening. Deterioration of bone properties due to ageing and disease can lead to an increase in the risk of pin loosening. This study determines the extent, locations and mechanics of bone yielding for unilateral external fixation systems at the tibial midshaft with changes in age-related bone structure and properties.

Investigation of factors affecting loosening of Ilizarov ring-wire external fixator systems at the bone-wire interface.

The potential for peri-implant bone yielding and subsequent loosening of Ilizarov ring-wire external fixation systems was investigated using non-linear finite element (FE) analyses. A strain-based plasticity model was employed to simulate bone yielding. FE models also incorporated contact behavior at the wire-bone interface, orthotropic elasticity, and periosteal-endosteal variation of bone properties.