The olecranon sled--a new device for fixation of fractures of the olecranon: a mechanical comparison of two fixation methods in cadaver elbows.

Background: Tension band wiring is the most common surgical procedure for fixation of fractures of the olecranon, but symptomatic hardware prominence and migration of K-wires can cause a high re-operation rate. The olecranon sled has been designed to minimize some of these problems.

Material And Methods: Simulated olecranon fractures were created in 6 matched pairs of cadaver arms. Each pair was fixed with tension band wiring used on the one arm and the olecranon sled being used on the other. Mechanical testing was done with the humerus rigidly fixed in a vertical position while the forearm was held at 1 of 3 angles of elbow fixation, 45 degrees , 90 degrees and 135 degrees , respectively. For each angle, the triceps and the brachialis muscles were sequentially loaded with 5 kg (50 N) for 20 cycles and the amount of fracture displacement measured.

Results: Loading of the brachialis muscle produced no increase in the fracture gap for either of the two fixation techniques. However, an increase in the fracture gap of up to 0.23 mm was found after cyclic loading of the triceps muscle for both techniques. The amount of increase was not significantly different between the two techniques.

Interpretation: The olecranon sled appears to provide as stable fixation as tension band wiring for olecranon fractures.