Effects of plate luting on cortical vascularity and development of cortical porosity in canine femurs.

A 4.5 mm, six hole dynamic compression plate was applied to the lateral aspect of one femur in 16 dogs. The plate was luted with polymethylmethacrylate (PMMA) in eight dogs. Four dogs each from the luted and nonluted groups were euthanatized at weeks 5 and 10. Plated femurs were sectioned and processed for microradiography, microangiography, and correlated histology. At week 5, there was decreased vascularity in the outer one third of the cortex beneath luted plates and normal to increased vascularity in the inner two thirds of the cortex. Increased cortical porosity and a decreased percentage of osteocyte-filled lacunae were found in the cortex beneath luted plates at week 5. At week 10, vascularity was increased throughout the cortex under luted plates. Under nonluted plates, there was normal to increased vascularity at both time periods. Luting a bone plate with PMMA decreased vascularity to the outer one third of the cortex beneath the plate at week 5, and resulted in accelerated resorption of bone.