Serum 1.25 dihydroxyvitamin D concentrations were reduced in elderly patients with femoral neck fractures, irrespective of the presence of osteomalacia. This reduction was not attributable to a decrease in vitamin D binding protein. The low rate of bone turnover in these elderly patients might reduce the requirement for vitamin D and protect against the development of osteomalacia. Serum vitamin D metabolite concentration cannot be used as a screening test for osteomalacia in these patients.

In this study 201 elderly patients with femoral neck fractures were compared with 30 osteomalacic patients with the same injury. Hypocalcaemia and a raised alkaline phosphatase level are common biochemical abnormalities in elderly patients with femoral neck fractures. In only a minority of patients, however, were they associated with histologically proven osteomalacia. By using the combination of hypocalcaemia and a raised alkaline phosphatase it is possible to identify a subgroup (approximately 10% of all admissions) in whom osteomalacia is relatively likely.

In a series of over 1000 elderly patients with femoral neck fracture, who were routinely screened by iliac crest bone biopsy, a 2% prevalence of osteomalacia was found. This low figure suggests that osteomalacia is not a significant predisposing factor in the development of these fractures and that routine screening is not cost-effective.