Bone Mineral Densities and Mechanical Properties of Retrieved Femoral Bone Samples in relation to Bone Mineral Densities Measured in the Respective Patients

The bone mineral density (BMD) of retrieved cancellous bone samples is compared to the BMD measuredin vivoin the respective osteoarthritic patients. Furthermore, mechanical properties, in terms of structural modulus (Es) and ultimate compression strength (σmax) of the bone samples, are correlated to BMD data. Human femoral heads were retrieved from 13 osteoarthritic patients undergoing total hip replacement. Subsequently, the BMD of each bone sample was analysed using dual energy X-ray absorptiometry (DXA) as well as ashing. Furthermore, BMDs of the proximal femur were analysed preoperatively in the respective patients by DXA. BMDs of the femoral neck and head showed a wide variation, from1016±166 mg/cm2to1376±404 mg/cm2. BMDs of the bone samples measured by DXA and ashing yielded values of315±199 mg/cm2and347±113 mg/cm3, respectively.Esandσmaxamounted to232±151 N/mm2and6.4±3.7 N/mm2. Significant correlation was found between the DXA and ashing data on the bone samples and the DXA data from the patients at the femoral head (r=0.85and 0.79, resp.).Escorrelated significantly with BMD in the patients and bone samples as well as the ashing data (r=0.79,r=0.82, andr=0.8, resp.).