Biomechanical evaluation of various fixation methods for proximal extra-articular tibial fractures

Proximal tibial fractures are a challenging clinical problem. The treatment protocols for these fractures include a dynamic compression plate (DCP), a locking compression plate (LCP), interlocking intramedullary nailing (IMN), and external fixation (Ex-Fix). However, the optimal fixation method for proximal tibial fractures remains controversial. The purpose of this study was to investigate the biomechanical properties of these four fixation instruments in the treatment of tibial proximal fractures.

Thirty-two tibial specimens were retrieved and randomly divided into four groups. Extra-articular proximal tibial fractures (AO classification 41-A2) were created in each specimen. The fractures were subsequently fixed by DCP, LCP, IMN, and Ex-Fix. The bone density of the proximal tibiae was examined by quantitative computed tomography. Each specimen was subjected to axial compression and three-point bending tests.

Bone mineral density did not significantly differ among the groups. In compression testing of the four fixation instruments, the highest degree of axial stiffness was found in the IMN group; there was no significant difference between DCP and LCP groups (P>0.05). The results of the three-point bending test revealed that DCP demonstrated the highest bending stiffness, which differed significantly from the other groups (P<0.05). The Ex-Fix had the lowest level of stiffness during the compression and three-point bending tests.

IMN has good mechanical properties, but its clinical application for proximal tibial fractures often leads to malalignment deformities. Compared with DCP, LCP is strong enough to fix the proximal tibial fractures and has the additional benefit of minimally invasive surgery.