Evaluation of strength of healing fractures with dual energy Xray absorptiometry

Dual energy xray absorptiometry was investigated as a method for evaluation of the strength of closed tibial fractures. In 40 goats, a closed midshaft fracture was created in the left tibia. The fractures were stabilized with an external fixator, After 2 weeks (n = 21) and after 4 weeks (n = 19), bo th tibias were explanted and, using dual energy xray absorptiometry, bone m ineral density and bone mineral content were measured in a 1 cm region. Wit h nondestructive bending tests, area ratio and stiffness index were determi ned and torsional strength and torsional stiffness were determined with a t orsional test to failure. Linear regression analysis was used to calculate the squared correlation coefficients for the relations between dual energy xray absorptiometry and the outcome of the mechanical tests. The squared co rrelation coefficients for the relation between bone mineral density and to rsional strength, torsional stiffness, and area ratio and stiffness index w ere 0.72, 0.76, 0.64, and 0.72, respectively. The squared correlation coeff icients for the relation between bone mineral content and these mechanical parameters were 0.72, 0.77, 0.63, and 0.77, respectively. The results using dual energy xray absorptiometry indicate the strength of healing closed fr actures. Additional research is required to investigate specific aspects of this technique.