Determination of Bone Density and Bone Composition Using Thermoaravimetric Analysis

Surgically obtained cancellous bone samples from the human osteoarthritic femoral heads (n=10) were used to measure bone mineral density (BMD) and the total amount of organic components. BMD was determined by thermogravimetric analysis (TGA), dual X-ray absorptiometry (DXA) and ashing. Furthermore, bone composition (amount of inorganic versus organic components) was analyzed with TGA. The measurement data showed a high linear correlation between TGA and DXA with r = 0.82 (p < 0.01) and between TGA and ashing with r = 0.83 (p < 0.01). Comparison of bone density values from DXA versus ashing revealed a correlation coefficient of r= 0.81 (p < 0.01). Between 200°C and 600 °C, a reduction of the bone sample mass of about 50 % was measured with TGA due to loss of organic components. TGA demonstrates its suitability to analyze bone mineral density and bone composition of samples derived from osteoarthritic patients.