The Journal of Bone and Joint Surgery, Vol 67, Issue 2 274-283, Copyright © 1985 by Journal of Bone and Joint Surgery, Inc
The effect of age on bone composition and viability in the femoral head
SY Wong, J Kariks, RA Evans, CR Dunstan and E Hills
We studied the effect of age on bone composition and osteocyte viability in
femoral heads from fifty-one subjects. The assessment included
determination of: bone volume, ash weight, calcium, and phosphorus content;
osteocyte viability in fresh sections stained for lactate dehydrogenase
activity; microfractures in fresh sections after removal of marrow
elements; bone area, the presence of metabolic bone disease, and the
histology of microfractures in embedded calcified sections; and the extent
of trabecular microfractures. Bone area and numbers of microfractures were
also assessed in eight elderly hip-fracture patients. Bone volume decreased
with age, but there was considerable variation in each age group, and no
significant difference between men and women. Ash weight and the bone
content of calcium and phosphorus also decreased with age, but were
constant if corrected for bone volume. Almost all osteocytes were viable in
subjects who were younger than twenty-five years, and thereafter viability
progressively decreased to a mean of 74 per cent in the eighth decade of
life. There was a significant negative correlation between osteocyte
viability and age. There was no evidence of metabolic bone disease in any
patient. The numbers of microfractures increased with age and correlated
negatively with bone viability (r = -0.31, p less than 0.05); in simple
linear correlation a relationship between bone area and microfractures
could not be demonstrated but in multiple linear correlation, after the
inclusion of bone viability, there was an additional negative correlation
between numbers of microfractures and bone area (p less than 0.005). Bone
area and numbers of microfractures in hip-fracture patients were similar to
those in age-matched controls.