In Vitro Mechanical Comparison of 2.0 and 2.4 Limited-Contact Dynamic Compression Plates and 2.0 Dynamic Compression Plates of Different Thicknesses

OBJECTIVE: To compare the bending structural stiffness and bending strength of thick and thin 2.4 mm limited contact dynamic compression plates (2.4 LC-DCP), 2.0 mm LC-DCP (2.0 LC-DCP), and 2.0 dynamic compression plates (2.0 DCP). STUDY DESIGN: In vitro mechanical study. METHODS: Two thicknesses of 2.4 LC-DCP, 2.0 LC-DCP, and 2.0 DCP stainless-steel plates were tested in 4-point bending. Data were collected during bending until implants plastically deformed. Bending structural stiffness and bending strength were determined from load displacement curves. Mechanical properties were compared between plates and the effects of plate type, size, and thickness on stiffness and strength were assessed using ANOVA. RESULTS: The thick 2.4 LC-DCP implant was the stiffest and strongest; the thin 2.0 DCP implant was most compliant and weakest. Larger sized plates, thicker plates, and limited contact design of plates enhanced stiffness and strength. For the plates studied, plate size had a larger effect than plate type or thickness on stiffness and strength. CONCLUSION: Increasing the size (width) and thickness of plates increases both the bending structural stiffness and strength. For the plates studied, LC-DCP implants were stiffer and stronger than DCP implants. CLINICAL RELEVANCE: Plate bending structural stiffness and strength can be most effectively enhanced by using a larger sized plate, but gains can also be achieved by using a thicker plate and/or an LC-DCP instead of a DCP implant when possible.