A quantitative technique for comparing synthetic porous hydroxyapatite structures and cancellous bone

There are many different materials currently available for cancellous bone grafting. There is however, very little information relating the morphology of these materials to cancellous bone. Work was undertaken to develop a quantitative method for comparing synthetic hydroxyapatite bone structures with cancellous bone. The bases for comparison were mean plate thickness, mean plate distance, mineral area fraction, mineral volume fraction and plate orientation coupled with mechanical tests. The aim of this work was to develop a protocol for assessing whether these critical parameters which influence the success of bone implants were achieved in the synthetic materials. The methodology is successful in providing quantitative information about the mineral area fraction, the mean plate distance or pore size and the intercept frequency as a function of angle. Combining these three provides a quantitative measure of how much mineral there is and how it is distributed and oriented. The mechanical tests yield strengths and moduli values based on apparent density. The results of the mechanical tests can also be plotted as functions of the more discrete structural features such as those quantified in the image analysis to allow for even more equitable and systematic comparisons of different porous materials.