Biomechanical Comparison of Intramedullary Fibular Nail Versus Plate and Screw Fixation

Clinical evidence has shown that percutaneous ankle fracture fixation using an intramedullary fibular nail results in good outcomes at 1 year and reduces postoperative wound complications in patients with vulnerable soft tissues. Confirmatory biomechanical evidence of its strength when used to secure a supination external rotation (SER) IV (AO/OTA 44B-type) fracture, compared with traditional plates and screws, is currently lacking.

Twenty cadaveric lower limbs (10 cadavers) had a SER IV injury surgically created. One leg was randomly allocated to fixation with a fibular nail and the other a lag screw and neutralization plate. A mechanical testing apparatus subjected all lower limbs to an axially loaded supination external rotation force to failure.

Superior ultimate torque to failure was demonstrated with a trend toward increased energy absorption in the nail group ( P = .28 and .07, respectively). No difference was demonstrated in angle at failure. All specimens in the plate group lost reduction at the bone-metal interface as a result of screw pullout. In contrast, all specimens in the nail group failed because of disruption of the lateral ligaments.

This study demonstrated greater torque to failure and better maintenance of the fibular construct for the intramedullary fibular nail compared to standard plating.

These results suggest that the previously documented clinical benefits of the fibular nail are complemented by biomechanical properties that compare favorably to standard techniques.