BIOMECHANICAL COMPARISON OF FIXATION METHODS IN TRANSVERSE OLECRANON FRACTURES - A CADAVERIC STUDY

Objectives/Hypothesis: Our null hypothesis was that no difference in f racture displacement would be detected between traditional monofilamen t wire and Kirschner wire placement versus three modified tension-band techniques for transverse olecranon fractures. Study Design: A nested form of the repeated measures design with twenty-two paired embalmed elbows (subjects grouped by sex and nested within the fracture method) . Methods: Transverse osteotomies were created at the olecranon and st abilized with four techniques. One hundred cycles of loading were appl ied to achieve a peak flexion bending moment at the fracture of nine n ewton-meters. At the onset of testing, the triceps tendon was anchored at an initial elbow flexion angle of 70 degrees. Results: When using a monofilament figure-eight loop, oblique Kirschner wire placement int o the anterior ulnar cortex provided greater resistance to tensile for ce than intramedullary Kirschner wires (p = 0.04). With intramedullary Kirschner wire placement, 1.6-millimeter-diameter braided cable in bo th figure-eight (p < 0.0001) and circular loop (p < 0.0001) designs al lowed less fracture displacement than did the 1.0-millimeter-diameter monofilament wire. There was no difference between figure-eight and ci rcular loop configurations when using braided cable (p = 0.98). Conclu sions: In transverse noncomminuted olecranon fractures, fixation with monofilament wire is superior with Kirschner wire placement into the a nterior ulnar cortex. With intramedullary Kirschner wires, fixation us ing braided cable is significantly improved over that with monofilamen t wire. When using braided cable, figure-eight and circular loop desig ns allow similar displacements. Braided cable or anterior cortical Kir schner wire purchase increases the stability of fixation over that ach ieved with the traditional method.