Biomechanical evaluation of carbon fiber-reinforced polyether ether ketone versus titanium plates for fixation of high tibial osteotomy.

BACKGROUND: Carbon fiber-reinforced polyether ether ketone (CFR-PEEK) plates have been introduced for medial opening-wedge high tibial osteotomy as an alternative to metallic fixation, offering potential advantages in radiolucency and elastic modulus; however, their construct-level biomechanical behavior and failure characteristics relative to titanium plates remain incompletely defined. Our purpose was to compare the biomechanical performance, stiffness, and failure mechanisms of similarly-shaped titanium and CFR-PEEK plates used for fixation of medial opening-wedge high tibial osteotomy in a controlled composite bone model. METHODS: Composite tibiae underwent standardized medial opening-wedge osteotomy and fixation with either a titanium or CFR-PEEK plate. Specimens were subjected to either quasistatic axial compression to failure or cyclic fatigue loading with motion analysis. Groups were compared using unpaired two-tailed t-tests. FINDINGS: During quasistatic testing, titanium constructs failed through rupture of the lateral cortical bone, whereas CFR-PEEK constructs failed through plate-related mechanisms at lower loads. Mean failure loads were higher for titanium constructs, although this difference did not reach statistical significance. Titanium constructs demonstrated significantly greater lateral stiffness at failure (p = 0.039). During fatigue testing, titanium constructs demonstrated higher mean failure loads and cycles to failure, but no statistically significant differences were observed. Failure modes remained distinct between groups. INTERPRETATION: Although both constructs withstood physiologic loading ranges, differences in construct stiffness, displacement behavior, and failure mechanism may influence osteotomy stability and maintenance of correction. Construct-level displacement and failure mode should therefore be considered when selecting fixation materials for medial opening-wedge high tibial osteotomy.