Characterisation of the material properties of bone in health and disease
This thesis describes a study characterising some of the material properties of cancellous bone from patients suffering from either osteoporosis or osteoarthritis whose femoral heads were surgically removed during hip replacement operations. For comparison, a variety of animal bones, having a range of mineral contents, and synthetic hydroxyapatite were also studied. These material properties were studied using the following techniques: thermogravimetric analysis linked to mass spectrometer (TGA-MS), powder x-ray diffraction (PXRD), mercury intrusion porosimeter (MIP) and high-temperature x-ray diffraction (HTXRD). The animal bones used were deer antler, whale periotic fin, whale ear bone, whale tympanic bulla, cod clythrum and porpoise ear. The TGA-MS determined the organic and the mineral proportions in bone and within the mineral the amount of the different types of carbonate was identified and quantified. The PXRD was used to measure the lattice dimensions and the crystallite sizes of human bone in order to find out if these parameters are altered in diseased bone. In synthetic hydroxyaptite (SHA), the PXRD was employed to determine the optimum sintering temperature as well as for monitoring the phase change that occurred when SHA was heated to high temperature. Phase monitoring was further carried in two of the animal species using HTXRD. This was used in preference to post-sinter-quenching of samples in order to obtain true, in-situ measurements of the composition at each temperature.