Osteomalacia in fractures of the proximal femur.

The occurrence of osteomalacia was studied in 58 hip fracture patients who were admitted to the University Central Hospital of Kuopio for operative treatment. Findings indicating osteomalacia were frequent in the series. Hypocalcaemia was found in 70 per cent and an increase in serum alkaline phosphatase in 22 per cent of the patients. Urinary calcium excretion was decreased in 45 per cent and urinary hydroxyproline excretion was increased in 70 per cent of the cases. The serum levels of 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D were significantly decreased in the patients compared with the controls. Histomorphometric analysis revealed no difference in the amount of trabecular bone in the patients compared with the controls, but the amount of osteoid and resorption surfaces was increased in the patients. Histological osteomalacia was found in 12 out of 50 patients (24 per cent). In 10 of these 12 cases the diagnosis of osteomalacia was supported by biochemical changes. There was only one patient, a 29-year-old man with glutein enteropathy who had an evident reason for osteomalacia. The most obvious cause of osteomalacia was the lack of vitamin D due to a deficient diet and lack of exposure to sunlight. The conclusion drawn was that osteoporosis was the main cause and osteomalacia was an important aggravating factor in the bone fragility in these hip fracture patients.