Interference Kirschner wires augment distal humeral fracture fixation in the elderly

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.

Ex vivo paired cadaveric study.

Biomechanical laboratory.

: Five pairs of fresh, elderly cadaveric humeri.

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.

Fixation survival was defined as 5000 cycles or the number of cycles until osteotomy site motion reached >2 mm.

K-wire augmented fixations survived significantly more cycles than did controls (4410 +/- 875 vs. 1114 +/- 2182, respectively; paired t test, P < 0.05).

Augmentation with K-wires may decrease the incidence of loss of fixation in distal humeral fractures.