Fibular rush rod fixation utilizing a threaded screw versus smooth pin: A cadaveric comparison study

Background

Open fibular fixation with plate osteosynthesis as an adjunct to increase stability has been associated with wound complications. Various percutaneous treatment options have been explored, but incompletely evaluated in comparison to one another in terms of rigidity of fixation at the fracture site.

Methods

A biomechanical study was performed with 9 pairs of matched cadavers after creation of a suprasyndesmotic fracture model as occurs in association with a tibial pilon fracture. One group in each pair was assigned to threaded screw and the other to smooth pin fixation. Displacement at the fracture site was evaluated before and after cyclic axial and rotational loading with an MTS frame through video dimensional analysis.

Results

In vertical loading alone, smooth pin and threaded screw fixation demonstrated no significant difference in displacement and there was no change in performance before and after loading cycles. With external rotation combined with a modest vertical load, screw fixation demonstrated smaller displacements than pin fixation, but the difference was less than 1 mm.

Conclusions

The results suggest that both smooth pin fixation and threaded screw fixation can achieve stable fixation in a transverse fibular fracture. There is less motion with use of a threaded screw when loading in axial rotation and external rotation, potentially recommending this option as a more rigid construct for percutaneous fixation of simple fracture patterns.