Quantitative and comparative stress analysis in human femur under two different static situations by three-dimensional photoelasticity.

Using the three-dimensional photoelastic method a quantitative analysis was carried out on the tension trends in the proximal third of a normal human femur in a stationary weight-bearing situation on two legs. The results obtained show that in this loading situation the maximum stress values (both for tension and compression) are in the area just below the subtrochanteric zone; while going up along the borders of the diaphysis, the tension trends do not vary appreciably. Moreover, the state of the stresses is not constant but varies slightly along the thickness of the bone. The neutral axis is considerably displaced towards the tensile area. A comparison between the stress tension trends in two different static loading situations (one-leg and two-leg support) was carried out. It was found that the maximum tensile stress value in the one-leg position was about 24 times greater than that in the two-leg position and the maximum compression stress value was about 14 times greater than in the two-leg situation.