Interference Kirschner Wires Augment Distal Humeral Fracture Fixation in the Elderly

OBJECTIVES: This study was designed to compare the biomechanical stability of a two-plate distal humerus fixation with and without Kirschner-wire (K-wire) augmentation of supracondylar osteotomies. DESIGN: Ex vivo paired cadaveric study. SETTING: Biomechanical laboratory. MATERIALS: : Five pairs of fresh, elderly cadaveric humeri. INTERVENTION: Two 3.5-mm reconstruction plates were used to stabilize each humerus. This fixation model was selected solely to evaluate the effect of K-wire augmentation. Augmentation consisted of 2 K-wires placed in both the medial and lateral columns of the humerus to interdigitate with the plate screws. A posteriorly directed load was cyclically applied to the distal fragment for 5000 cycles or until failure, and osteotomy site motion was tracked optically. MAIN OUTCOME MEASUREMENTS: Fixation survival was defined as 5000 cycles or the number of cycles until osteotomy site motion reached >2 mm. RESULTS: K-wire augmented fixations survived significantly more cycles than did controls (4410 +/- 875 vs. 1114 +/- 2182, respectively; paired t test, P < 0.05). CONCLUSIONS: Augmentation with K-wires may decrease the incidence of loss of fixation in distal humeral fractures.