Finite element analysis of intramedullary devices: the effect of the gap between the implant and the bone.

This paper examines the interaction interface between the implant and the bone for an intramedullary femoral nailing system using a finite element (FE) model and specifically considers the hypothesis that the local geometry at the interface is significant to the resulting localized contact stress between the medial and lateral aspect of nail and endosteum. Contact mechanics algorithms are used in the FE modelling technique that can be developed to deal with any form of intramedullary device for which contact at the bone-implant interface is important. Global stiffness data from the FE model are compared with available data from an experiment carried out on a construct of the bone and the device that uses intramedullary femoral nails.

Intramedullary nails with two lag screws.

Objective: To investigate the structural integrity of intramedullary nails with two lag screws, and to give guidance to orthopaedic surgeons in the choice of appropriate devices.

Design: Alternative designs of the construct are considered, and the use of a slotted upper lag screw insertion hole is analysed.

Background: Intramedullary fixation devices with a single lag screw have been known to fail at the lag screw insertion hole.

Intramedullary nails: some design features of the distal end.

Intramedullary nails are used to stabilise fractures of the proximal femur. The nail acts by transferring loads from the proximal fraction to the rest of the femoral shaft. The way in which this occurs depends to a large extent on the design of the distal end of the nail.

Intramedullary femoral nails: one or two lag screws? A preliminary study.

Failures of proximal femoral nails that treat unstable femoral fractures have been reported. In this communication, a finite element model to include a proximal femoral nail within a fractured femur was used to carry out preliminary investigations into configurations of single or double lag screws. The effects of the different types of fracture were investigated.

Some factors that influence mechanical behavior of the left ventricle of the human heart in late systole: a feasibility study using finite element analysis.

In systole the left ventricle of the heart behaves mechanically in two modes simultaneously, passive and active. When in the former mode, the ventricle has to carry and react to the pressure increase within the cavity, while in the latter, force is generated within the myocardium itself through the contraction, i.e.