How cross screw length influences the stiffness of intramedullary nail systems

S V Karuppiah,A J Johnstone,Duncan E.t Shepherd

doi:10.4236/jbise.2010.31005

S V Karuppiah, A J Johnstone + Show 1 more

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https://doi.org/10.4236/jbise.2010.31005

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Abstract

Fractures of long bones are commonly treated with intramedullary (IM) nails and they have been shown to have a very high success rate. Recently we have concerns with the use of the newer IM nailing sys- tems, that uses longer cross screws, which have been developed with variation in implant designs. We be- lieve that the newer implants provide less fracture stability, due to decreased stiffness of the IM nailing system. The aim of this study was to biomechanically determine the influence of the length of cross screw on the stiffness of the IM nailing system, using a composite model. Our test results confirmed our sus- picion that the newer IM nailing system using longer cross screw-length is less stiff than traditional nailing systems using shorter cross screw length, during axial loading.

Highlights

Orthopaedic implants have been popular in the management of fractures for the last six decades
The aim of this study was to determine the influence of the cross screw length on the stiffness of fracture fixation when using IM nailing systems
The distal end of the intramedullary nail was secured to the cylinders with a single stainless steel rod of diameter 5 mm; this represented the cross screw

Summary

Introduction

Orthopaedic implants have been popular in the management of fractures for the last six decades. There are various types of implants available for fixation of bone fractures, intramedullary (IM) nails being one of them These are popular for the fixation of diaphyseal (shaft) fractures of the femur, tibia and humerus with high success rates. It is one of the accepted and most widely used methods of treating, transverse and short oblique, axially stable fractures of the femoral diaphysis [1,2,3,4]. It provides an excellent and prompt return of function with a low rate of complication and non-unions [5]. From time to time further changes in the design of the implant has been made, including the placement of the cross screws, to extend the use of femoral IM nails in all types of femoral fractures

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