Compressive properties of cancellous bone defects in a rabbit model treated with particles of natural bone mineral and synthetic hydroxyapatite

A rabbit model was developed to evaluate the compressive mechanical propert ies of cancellous bone defects treated with particles of selected bone graf t substitute materials. A novel feature of the model was the precise retrie val of the site of implantation. A notable finding was a 9-fold increase in the modulus of elasticity of the defect implanted with a synthetic hydroxy apatite material after 26 weeks when compared to the modulus of the trabecu lar bone normally at the site. The compressive modulus of lesions treated w ith particles of a natural bovine bone mineral (anorganic bovine bone) was closer to the normal modulus of the cancellous bone at the site. While the compressive strength of the anorganic bone particles was less than that of normal bone, the site implanted with the bone mineral particles achieved co mpressive strength greater than normal after 6 weeks. Moreover, the anorgan ic bone particles accelerated the increase in strength of the lesion, at 6 weeks exceeding the strength achieved by the untreated defect after 26 week s. The potential problem associated with the disparity in the compressive m odulus between sites implanted with the synthetic HA particles and surround ing bone is discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.