Evaluation of the Mechanical Performance of Carbon Fiber Reinforced PEEK Trauma Plates in Comparison with Commercially Pure Titanium Plates

Novel composition materials, such as continuous Carbon Fiber Reinforced Poly-ether-ether-ketone (CFR-PEEK) are beginning to see an increasing adoption in fracture fixation devices.  In this study, reported clinical failures of CFR-PEEK from Manufacturer and User Facility Device Experience (MAUDE) database have been summarized and analyzed for the first time. Among the reported plate and nail failures that occurred during the bone healing process postoperatively, 21.7% were identified to have been related to overload, such as falling, subsequent tragic accidents, and patient non-compliance, and getting into sports prematurely.  Mechanical overload tests to mimic the catastrophic failure were conducted on CFR-PEEK plates compared to conventional Titanium (Ti) plates. In addition, debris generated during the catastrophic failure was collected and characterized for the first time.  According to Wolf's law and Frost's theory, PEEK-OPTIMA TM Ultra Reinforced Image Contrast (POUR-IC) plates (Invibio Ltd) revealed potentially better bone healing properties and resistance to overload failure, with a relatively higher load tolerance (1108.78±17.82N) and lower stiffness (2.97±0.16 Nm 2 ), compared to both PEEK-OPTIMA TM Ultra Reinforced (POUR) plate (1229.35±93.83 N and 4.45±0.15 Nm 2 , respectively) and Ti plate (684.81±15.82 N and 3.45±0.18 Nm 2 , respectively).  While Ti plates showed no gravimetrical loss during the overload tests, POUR and POUR-IC exhibited a loss of 3.02±4.95 mg and 0.15±0.06 mg, respectively. Taking into consideration the debris generated during functional use within patients, the amount of debris from a Ti plate would be 8.95mg, which was around 2 times and 5.4 times than that of the POUR (4.51 mg) and POUR-IC (1.66mg).  Particle size distribution showed most of the debris from both CFR-PEEK plates were less than 5 µm, and its shape ranged from small irregular granules to medium fibrous and large irregular flakes.  Overall, the authors recommended POUR-IC as potentially the best choice of materials among the tested fracture fixation plates.  The authors acknowledge the study's limitation, such as the difference on the design parameters on the tested plates, and suggest further research into areas such as the relationship between the morphology of debris and the biological response.