[Measurement of bone mineral density of metacarpal and phalangeal bones of the hand by dual X-ray absorptiometry].
Bone mineral density (BMD) of the metacarpal and phalangeal bones of the hand was evaluated using dual X-ray absorptiometry (DXA) in 104 healthy subjects, 35 patients with rheumatoid arthritis (RA) and 6 young male volunteers with a short arm cast. BMD was positively correlated with the bone volume of metacarpal and phalangeal bones in skeletal specimens. In healthy subjects, the mean values for BMD of metacarpals of the index and middle fingers were significantly higher than those of the ring and little fingers (p < 0.001). The BMD of the middle proximal phalanx was the highest among the proximal phalanges. The BMD of the middle phalanges was the same pattern as in the proximal phalanges. There was no significant difference in the BMD of the distal phalanges between the fingers. In 62 healthy women aged from 22 to 82 years, BMD was at its peak in the metacarpal and proximal phalangeal bones in their thirties, and in the distal phalanges in their forties. Thereafter, BMD decreased linearly with age. In contrast, age-related changes in BMD were not shown in 42 healthy men aged from 22 to 76 years. BMD of the metacarpal and phalangeal bones in RA markedly decreased with disease stage. Four-week immobilization of the hand by a short arm cast affected BMD of the metacarpal bones in 6 healthy volunteers. The mean change in BMD was -4.1% after 4 weeks of immobilization, followed by a return to the initial value in 12 weeks after removal of the plaster. We concluded that the bone mineral measurement of metacarpal and phalangeal bones could be useful for evaluation of age-related bone loss and the deterioration of bone in metabolic disorders.