The effect of age on blood flow in the proximal femur in man.

blood flow in the proximal femur was measured in 45 healthy male and female adults by means of a Xe-133 washout method. On the basis of a two-compartment exponential model, blood flow was calculated assuming that the compartments were hematopoietic (red) marrow and nonhematopoietic tissues of bone. Between the ages of 20 and 55 the bone perfusion was 8.3 +/- 1.4 (1 s.d.) ml/100 g/min, decreasing thereafter in older patients. During the same period the red-marrow blood flow (RMBF) decreased linearly: RMBF (ml/100 g/min) = -0.14 x age + 24.5. The nonhematopoietic bone perfusion changed like the bone perfusion. The fractional masses of red marrow and nonhematopoietic tissues of bone in the greater trochanteric region of the femur were determined morphometrically from the bone biopsies of seven adult cadavers. They agreed with the values estimated by the Xe-133 washout method. The blood-flow values will be used as reference values for the Xe-133 bone circulation method.