Knutsen, A, MS, Sangiorgio, S N, PhD, Lui, C, Zhou, S, BS, Warganich, T, MD, Fleming, J, MD, Harris, T, MD, Ebramzadeh, E, PhD

Foot and Ankle Surgery, 22(4), 278-285., December 2016

Background: The goal of this study was to evaluate the biomechanical performance of three distal fibula fracture fixation implants in a matched pair cadaveric fibula model: (1) a 5-hole compression plate with lag screw, (2) a 5-hole locking plate with lag screw, and (3) the 6-hole tabbed-plate with locking screws.

Methods: Three-dimensional motions between the proximal and distal fibular segments were measured under cyclic valgus bending, cyclic compressive axial loading, and cyclic torsional external-rotation loading. During loading, strains were measured on the surface of each fibular near the simulated fracture site, and on the plate, to assess load transfer. Bone quality was quantified globally for each donor using bone miderl density (BMD) measured using Dual X-Ray absorptiometry (DEXA) and locally at the fracture site using bone mineral content (BMC) measured using peripheral quantitative computed tomography (pQCT).

Results: Mean failure loads were belowed 0.2 Nm of valgus beding and below 4Nm of external-rotational torque. Mean failure angulation was below 1 degree for valgus bending, and failure rotation was below 7 degrees for external-rotation. In the compression plate group, significant correlations were observed between bone quality (global BMD and local BMC) ans strain in every one of the five locatios (Pearson correlations coefficients >0.95, p <0.05). In contrast, in the locking and tabbed-plate groups, BMD and BMC correlated with far fewer strain locations.

Conclusions: Overall, the tabbed-plate had similar construct stability and strenght to the compression and locking plates. However, the distribution of load with the locking and tabbed-plates was not as heavily dependent on bone quality.