Displaced olecranon fractures in adults. Biomechanical analysis of fixation methods.

Four commonly used methods of internal fixation for displaced olecranon fractures were analyzed in a biomechanical model to determine strength of fixation. A transverse osteotomy in fresh cadaver specimens was internally fixed and was tested to failure by rapid loading. Screw plus wire in combination provided the greatest strength of fixation. Energy to failure averaged 31.0 Nm for cancellous screw, 32.0 Nm for figure-of-eight wire, 35.3 Nm for Arbeitsgemeinschaft fur Osteosynthesefragen (AO) tension band, and 39.4 Nm for screw-plus-wire combination. Comparison of screw and wire in combination to screw alone or to figure-of-eight wire demonstrated a significant difference (p less than 0.05). The difference between screw plus wire and AO tension-band fixation did not achieve statistical significance (0.2 greater than p greater than 0.1).