K-wire position in tension band wiring of the olecranon - a comparison of two techniques.

Tension band wiring is a recognised standard treatment for olecranon fractures. We studied the effect of K-wire position on backing out of the wire in a group of 80 patients with closed transverse olecranon fractures with a minimum follow-up time of 9 months. The rate of wires backing out as seen on X-ray was three times greater in patients who had K-wires passed down the long axis of the ulna rather than across the anterior cortex as recommended by the AO group. There was a corresponding higher rate of local complications in these patients. 42% of this group had to have the metal removed compared with 11.4% of the transcortical group. We compared the biomechanical properties of both K-wires positions in a human cadaveric model. The maximum pull-out strength for each configuration was recorded in 20 elbow joints. The average maximum pullout strength for the intramedullary wires was 56.3 N (range 27. 7-95.6 N) and 122.7 N for the transcortical wires (range 56.7-201.2). The results of both the clinical study and biomechanical data support the routine use of transcortical placement of K-wires in tension-band wiring of transverse olecranon fractures.