METACARPAL RADIOGRAMMETRY BY COMPUTED RADIOGRAPHY IN POSTMENOPAUSAL WOMEN WITH COLLES FRACTURE AND VERTEBRAL CRUSH FRACTURE SYNDROME

Based on the hypothesis that the underlying osteoporotic mechanism of Colles' fracture in postmenopausal women is similar to that of other o steoporotic fractures, that is, cortical bone resorption as opposed to cancellous bone resorption, the rate of corticoendosteal bone loss wa s compared in 40 normal postmenopausal women [average age 68.4 +/- 7.1 years; 20 +/- 4 years since menopause (YSM)], in 35 postmenopausal wo men with Colles' fracture (age 69.4 +/- 7.5 years, 22 +/- 8 YSM), in 3 5 normal postmenopausal women with vertebral crush fracture (age 69.4 +/- 7.5 years, 22 +/- 8 YSM, and in 35 normal premenopausal women (age 36.1 +/- 7.9 years). Radiogrammetry by digital radiography of the sec ond metacarpal was used to measure external (ED) and internal (ID) dia meter, cortical thickness (CCT), cortical area (CA), and the ratio of cortical area to total area (CA/TA). The ID values of the groups of po stmenopausal women were subtracted from the ID value of the premenopau sal women and the result was divided by YSM to obtain the rate of cort icoendosteal resorption/year (Delta C), CA resorption year (Delta CA) and CA/TA resorption/year (Delta CA/ TA). ID, Delta C, Delta CA, and D elta CA/TA all were larger in the postmenopausal women with Colles' an d vertebral crush fractures than in the normal postmenopausal women (A NOVA: all P < 0.0001). ID, CCT, Delta C, CA, Delta CA, and Delta CA/TA did not differ between the two groups of postmenopausal women with fr actures. Delta C was 87% greater in postmenopausal women with vertebra l crush fracture and 116% greater in women with Colles' fracture than in normal postmenopausal women. These results indicate that the loss o f cortical bone is an important factor in Colles' fracture in postmeno pausal women.