New intramedullary locking nail for olecranon fracture fixation--an in vitro biomechanical comparison with tension band wiring.

Background: The aim of this study was to determine the difference in displacement of a newly designed intramedullary olecranon fracture fixation device compared with multifilament tension band wiring after 4 cycles and 300 cycles of dynamic continuous loading.

Methods: In eight pairs of fresh-frozen cadaver ulnae, oblique olecranon fractures were created and stabilized using either newly designed intramedullary olecranon nail or multifilament tension band wiring. The specimens were then subjected to continuous dynamic loading (from 25 N to 200 N) using matched pairs of cadaveric upper extremities. The Wilcoxon test was used to determine statistical differences of the displacement in the fracture gap.

Results: After 4 cycles and 300 cycles, the displacement in the fracture model was significantly higher in the tension band wiring group than in the intramedullary nailing group.

Conclusions: The newly designed interlocking nailing system showed higher stability in comparison with multifilament tension band wiring after continuous dynamic loading.