A NEW ANATOMICAL PLATE FOR EXTRA-ARTICULAR DISTAL HUMERAL FRACTURES: BIOMECHANICAL STUDY

UMA NOVA PLACA ANATÔMICA PARA FRATURAS EXTRA-ARTICULARES DISTAIS DO ÚMERO: ESTUDO BIOMECÂNICO

ABSTRACT

Introduction

We compared the mechanical properties of two fixation techniques for the treatment of extra-articular distal third humeral fractures.

Materials and Methods

Two groups were created from twenty-four humeri. Group 1 was instrumented using a new, precontoured, 8-hole (3.5-mm-diameter) locking compression plate (LCP) placed anterolaterally. Group 2 was instrumented using an 8-hole (3.5-mm-diameter) precontoured posterolateral LCP plate placed on the distal humerus. Four-point bending tests and torsion tests were performed until the specimens broke.

Results

The four-point bending stiffness test showed that the stiffness of anterolaterally fixed humeri was significantly higher than that of posterolaterally fixed humeri (p<0.05). Torsion testing revealed that posterolateral fixation was associated with better yield strength (p<0.05), but the torsional stiffness did not differ significantly between the two plates (p> 0.05).

Conclusions

The anterolateral plate exhibited higher bending stiffness and torsional yield strength than the posterolateral plate. Anterolateral plate fixation can thus be used to manage extra-articular distal humeral fractures. Multiaxial locking screws ensure rigid fixation, allow early elbow motion without olecranon fossa impingement, and prevent iatrogenic injury of the triceps muscle. Level of Evidence I, Therapeutic Studies Investigating the Results of Treatment.

Fracture Fixation; Humeral Fractures; Fracture Fixation,Internal