Bone Mineral Density Alterations in Upper and Lower Extremities 12Months After Stroke Measured by Peripheral Quantitative Computed Tomography and DXA

Abstract 

To evaluate the loss of trabecular and cortical bone mineral density (BMD) and geometric parameters of bone strength expressed by stress-strain index (SSI) in the proximal and distal forearm and the alterations of BMD in the hip of hemiplegic patient and 12mo after stroke. Sixty-seven hemiplegic patients (43 men and 24 women) with a history of single completed strokes associated with unilateral weakness were enrolled in this prospective study. All patients underwent bone densitometry measurements at 3, 6, and 12mo after the initial episode of stroke. Both paretic and normal forearms were examined by peripheral quantitative computed tomography (pQCT) at the 4% and 20% sites of the forearm length and both hips were examined by dual-energy X-ray absorptiometry (DXA) including the area of femoral neck and greater trochanter. The diagnosis of stroke was confirmed by cranial computed tomography. Motor function was assessed by the functional ambulation category (FAC) and spasticity by the modified Ashworth scale (MAS). We found statistically significant trabecular and cortical bone density reductions during the course of our study in the forearm, which was more profound on the paretic side. Trabecular bone loss and SSI measured at 4% of the paretic forearm in the male group represented a 12-mo decrease of 14.01% and 28.61%, respectively, and in the female group 9.29% and 19.17%, respectively. Cortical bone and SSI measured at the 20% site of paretic forearm in the male group corresponded to a 12-mo decrease of 4.02% and 7.43%, respectively, and in the female group 2.59% and 6.97%, respectively. Paretic femoral neck and trochanter measurements in males showed a reduction of 11.76% and 10.38%, respectively, and in females 13.04% and 12.6%, respectively. A significant loss of BMD and bone strength was found during the first year after stroke in both trabecular and cortical bone at the forearm and at the neck and great trochanter on the paretic hip. Most prominent BMD reduction was evident in men compared with perimenopausal women in the same age.

Key Words: bone mineral density, DXA, osteoporosis, pQCT, stroke