Biomecânica de quatro técnicas de fixação da fratura em quatro partes da cabeça umeral

Elpídio Da Graça,Nilton Mazzer,Cláudio Henrique Barbieri,Antônio Carlos Shimano,Rodrigo Okubo

doi:10.1590/s1413-78522013000100007

Elpídio Da Graça, Nilton Mazzer + Show 3 more

Open Access

https://doi.org/10.1590/s1413-78522013000100007

Copy DOI

Abstract

OBJECTIVE: To carry out a biomechanical study of four techniques for fixation of four-part humeral head fractures. METHODS: The fracture was reproduced in 40 plastic humeri, divided into groups of ten according to the fixation technique, each one employing different fixation resources, in different configurations. The humeral models were mounted on an aluminum scapula, with leather straps simulating the rotator cuff tendons, and submitted to bending and torsion tests in a universal testing machine, using relative stiffness as an evaluation parameter. Assemblies with intact humeri were analyzed for comparison. RESULTS: The biomechanical behavior of the fixation techniques varied within a wide range, where the assemblies including the DCP plate and the 4.5mm diameter screws were significantly more rigid than the assemblies with the Kirschner wires and the 3.5mm diameter screws. CONCLUSION: The four fixation techniques were able to bear loads compatible with the physiological demand, but those with higher relative stiffness should be preferred for clinical application. Laboratory investigation .

Highlights

High energy accidents have increased over the last decades, resulting in an increased incidence of severe fractures and fracture-dislocations, including those affecting the proximal end of the humerus in young and middle-aged patients, with great potential for functional sequelae
The biomechanical behavior of the fixation techniques varied within a wide range, where the assemblies including the DCP plate and the 4.5mm diameter screws were significantly more rigid than the assemblies with the Kirschner wires and the 3.5mm diameter screws
The four fixation techniques were able to bear loads compatible with physiological demands, but those with higher relative stiffness should be preferred for clinical application

Summary

Introduction

High energy accidents have increased over the last decades, resulting in an increased incidence of severe fractures and fracture-dislocations, including those affecting the proximal end of the humerus in young and middle-aged patients, with great potential for functional sequelae. Circa 80% of the fractures of the proximal end of the humerus are two-fragment fractures, with no significant displacement, most of which are stable and suitable for some type of closed conservative or functional treatment. The remaining 20% are three- or four-fragment unstable deviated fractures, quite often compromising the blood supply to the humerus head dome, with consequent necrosis.[1,2] Four-fragment fractures may be a quite challenging problem concerning both precise diagnosis and treatment. Avascular necrosis of the head dome fragment is a frequent complication, regardless of the type of treatment and fixation technique, and most authors agree that it is quite often an asymptomatic condition, not requiring any further surgical measure.[1,6,7,8] Percutaneous pinning, bone sutures, tension band wiring, intramedullary nailing, fragment specific screw fixation, and various types of plates (T-shaped, angled and blocked plates) are among the proposed fixation techniques for such complex

Methods

Results

Conclusion