Biomechanical evaluation of intramedullary nail versus tension band fixation for transverse olecranon fractures

Objectives: To compare the biomechanical stability of an alternative custom-designed intramedullary nail (IMN) fixation with that of traditional tension band wiring (TBW), the gold standard for stabilizing transverse olecranon fractures. Design: Ex vivo biomechanical study. Setting: Biomechanical laboratory. Materials: Six pairs of elderly cadaver elbows. Intervention: A simulated transverse olecranon fracture was created in each elbow after it had been denuded of most of its soft tissue. The right and left olecranons of each pair were alternately assigned to the IMN or TBW group. A tensile force was applied via the triceps tendon while the elbow was secured in 90° of flexion. Main Outcome Measurements: Displacement at the simulated fracture segment was measured optically. Fixation failure was defined as >2 mm of fracture displacement. The differences in stiffness and maximum load to failure between the two treatments were analyzed for significance (P < 0.05) using a one-tailed paired t test. Results: IMN fixation was significantly stiffer and stronger than TBW fixation. Conclusions: The locked IMN provided stronger and stiffer fixation than did TBW. Theoretically the IMN fixation would require less surgical exposure and would be expected to require fewer revisions than TBW fixation. IMN fixation warrants consideration as a clinical alternative to TBW.