title: Mechanisms of cortical bone loss from the metacarpal following digital amputation.
abstract: Immobilization bone loss, whether due to whole body immobilization or local causes, is associated with an initial rapid phase of trabecular bone loss, but the long-term effects of immobilization on cortical bone are not well described. We have studied metacarpal morphometry in 16 men who had undergone partial or complete traumatic digital amputations 4-71 years earlier. Noninvolved metacarpals from the affected and unaffected hands were used as controls. Cortical bone width was significantly reduced in the metacarpals proximal to the amputated digits (P = 0.001). In the 7 subjects who suffered amputation before the age of 19, the cortical bone deficit was primarily due to a reduction in the total width of the medullary shaft (P = 0.007), whereas medullary width was not changed. In these subjects the metacarpal was also significantly reduced in length, by a mean 2.9 mm (P = 0.35). In the 9 subjects who had their amputation after the age of 19, both a reduction in total width and an increase in medullary width (P = 0.017) accounted for the cortical bone deficit. The deficit in total width was related to the time since amputation (P = 0.008) and could be accounted for by loss of the normal age-related increase in total width (0.01 mm/year). We conclude that in this model of immobilization osteoporosis, the metacarpal proximal to the amputated digit demonstrates cortical osteopenia.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, Auckland Hospital, New Zealand.
authors.forename: T
authors.initials: T
authors.lastname: Cundy
authors.forename: A
authors.initials: A
authors.lastname: Grey
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000671:Amputation, Surgical / Q000009:adverse effects*; D001851:Bone Diseases, Metabolic / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D005385:Fingers / Q000601:surgery*; D006801:Humans; D007103:Immobilization / Q000502:physiology; D008297:Male; D008663:Metacarpus / Q000473:pathology / Q000503:physiopathology*; D008875:Middle Aged; D010024:Osteoporosis / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors