Biomechanical comparison of fixation methods in transverse olecranon fractures: a cadaveric study.

OBJECTIVES/HYPOTHESIS: Our null hypothesis was that no difference in fracture displacement would be detected between traditional monofilament 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 stabilized with four techniques. One hundred cycles of loading were applied to achieve a peak flexion bending moment at the fracture of nine newton-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 into the anterior ulnar cortex provided greater resistance to tensile force than intramedullary Kirschner wires (p = 0.04). With intramedullary Kirschner wire placement, 1.6-millimeter-diameter braided cable in both figure-eight (p < 0.0001) and circular loop (p < 0.0001) designs allowed less fracture displacement than did the 1.0-millimeter-diameter monofilament wire. There was no difference between figure-eight and circular loop configurations when using braided cable (p = 0.98).

CONCLUSIONS

In transverse noncomminuted olecranon fractures, fixation with monofilament wire is superior with Kirschner wire placement into the anterior ulnar cortex. With intramedullary Kirschner wires, fixation using braided cable is significantly improved over that with monofilament wire. When using braided cable, figure-eight and circular loop designs allow similar displacements. Braided cable or anterior cortical Kirschner wire purchase increases the stability of fixation over that achieved with the traditional method.