Biomechanics of cancellous bone with avascular necrosis

The mechanical properties of the dry and wet, decalcified and non-decalcified cancellous bones were measured in normal and necrotic districts of avascular necrosis of the femoral head (ANFH) using compression tests with mathematic models developed for various stress-strain relationships. An analysis based on the mechanics of bones with various compositions shows that the collagen in necrotic bone is more than in normal bones, but the inorganic salts are less. Normal and necrotic dry bones are also observed using an atomic force microscope (AFM) to prove the conclusion. Different models have different stress-strain curves which can be classified into three kinds of experimental curves or constitutive equations.