Biomechanical comparison of the new cross-locking intramedullary nail with tension band wiring for transverse olecranon fractures

In the treatment of transverse olecranon fractures, complicated tension band wiring (TBW) has high rates of re-operations. Besides, plate fixation (PF) and TBW both have large surgical incisions and soft-tissue irritation. Therefore, the new cross-locking intramedullary nail (CIN) with easy handling and minimally invasive features is significantly advantageous. The goal of this study was to biomechanically compare CIN with TBW for fixing transverse olecranon fracture. The transverse olecranon fracture models were created with 15 fresh-frozen cadaveric ulnae which were randomly divided into 3 groups: one group for TBW fixation, another for CIN fixation with 1 conical locking screw (CIN-1), and the last for CIN fixation with 3 conical locking screws (CIN-3). The stiffness, cyclic stability, and failure strength of the fixed fracture models were compared after the corresponding experimental tests. The failure strength of TBW, CIN-1 and CIN-3 were (313.38±27.68) N, (528.56±53.58) N and (871.04±94.95) N. There was a significant difference between them. However, as for dynamic stability and stiffness, CIN-3 was higher and TBW was lower, with no significant differences between the groups. The biomechanical properties of CIN were superior to those of TBW, and CIN was more stable and solid for fixing transverse olecranon fracture, of which CIN-3 was the strongest.