Biomechanical comparison of tension band wiring and plate fixation with locking screws in transverse olecranon fractures.

BACKGROUND

Tension band wiring (TBW) is the standard method for treating transverse olecranon fractures, but high rates of complications and reoperations have been reported. Plate fixation (PF) with locking screws has been introduced as an alternative method that may retain the fracture reduction better with a higher load to failure.

METHODS

Twenty paired cadaveric elbows were used. All soft tissues except for the triceps tendon were removed. A standardized transverse fracture was created, and each pair was allocated randomly to TBW or PF with locking screws. The triceps tendon was mounted to the materials testing machine with the elbow in 90° of flexion. Construct stiffness was compared 3 times. Then, the elbows underwent a chair lift-off test by loading the triceps tendon to 300 N for 500 cycles. Finally, a load-to-failure test was performed, and failure mechanism was recorded.

RESULTS

The construct stiffness of PF was higher in the first of 3 measurements. No difference was observed in the cyclic test or in load to failure. Hardware failure was the failure mechanism in 8 of 10 TBW constructs, and all failures occurred directly under the twists of the metal wire. Hardware failure was the cause of failure in only 1 elbow in the PF group (P < .01).

CONCLUSION

There was no difference in fracture displacement following fixation with TBW and PF with locking screws in transverse olecranon fractures. However, assessment of the mode of hardware failure identified the metal cerclage twist as the weakest link in the TBW construct.