Abstract
Avulsion fractures of the tip of the olecranon are a common traumatic injury. Kirshner-wire fixation (1.6mm) with a figure of eight tension band wire (1.25mm) remains the most popular technique. Hardware removal mat be required in up to 80% of cases. Modern suture materials have very high tensile strength coupled with excellent usability. In this study we compare a repair using 1.6mm k-wires with a 1.25mm surgical steel, against a repair that uses two strands of 2 fibrewire.
Twelve Pairs of cadaveric arms were harvested. A standard olecranon osteotomy was performed to mimic an avulsion fracture. In each pair one was fixed using standard technique, 2 × 1.6mm transcortical ?-wire plus figure of 8 loop of 1.25mm wire. The other fixed with the same ?-wires with a tension band suture of 2.0 fibrewire (two loops, one figure of 8 and one simple loop). The triceps tendon was cyclically loaded (10-120 Newtons) to simulate full active motion 2200 cycles. Fracture gap was measured with the ‘Smart Capture’ motion analysis system. The arm was fixed at 90 degrees and triceps tendon was loaded until fixation failure, ultimate load to failure and mode of failure was noted.
The average gap formation at the fracture site for the suture group was 0.91mm, in the wire group 0.96mm, no specimen in either group produced a significant gap after cyclical loading. Mean load to failure for the suture group was 1069 Newtons (SD=120N) and in the wire group 820 Newtons (SD=235N).
Both types of fixation allow full early mobilisation without gap formation. The Suture group has a significantly higher load to failure (p=0.002, t-test). Tension Band suture allows a lower profile fixation, potentially reducing the frequency of wound complications and hardware removal.
