Influence of Plate Design on Cortical Bone Perfusion and Fracture Healing in Canine Segmental Tibial Fractures

OBJECTIVE: To investigate whether or not the limited contact design of the low-contact dynamic compression plate (LCDCP) provides advantages over the dynamic compression plate (DCP) in the context of cortical bone blood flow, biomechanical properties, and remodeling of bone in segmental tibial fractures. DESIGN: Randomized trial using canines. SETTING: Animal research laboratory. PARTICIPANTS: Eleven canines. INTERVENTION: Segmental tibial fractures were surgically created in canine tibiae. The tibiae were reduced and stabilized with 316L stainless-steel, 3.5-millimeter, ten-hole plates: LCDCP (n = 5) or DCP (n = 6). MAIN OUTCOME MEASUREMENTS: Laser Doppler flowmetry evaluated cortical bone perfusion in the proximal tibia, segmental piece, and distal tibia (a) before fracture, (b) after fracture, (c) immediately after plating, and (d) at ten weeks. After the dogs were killed at ten weeks, bending stiffness and load to failure of the tibiae were assessed. Tibial cortical bone porosity and new bone formation were measured. RESULTS: Cortical bone blood flow was similar between the LCDCP and DCP groups throughout the study. Bending stiffness and load to failure of the tibiae were similar between the two groups. Whereas cortical bone porosity and new bone formation were higher in all plated tibiae at ten weeks compared with controls, no differences in cortical bone porosity were seen between the LCDCP and DCP groups. There was a trend toward significantly more new bone formation in the LCDCP group. CONCLUSION: The LCDCP is not advantageous in fracture healing or restoration of cortical bone perfusion to devascularized cortex in segmental fractures when plate fixation has been chosen for fracture stabilization. The overall injury following segmental devascularization seems more important to outcome than the type of implant used for fracture fixation up to ten weeks.