Trabecular Bone Scores and Bone Fractures in Diabetes Patients with and Without a Charcot Foot - Abstract
The collapse of bones in the Charcot foot may be caused by other factors than decreased bone mineralization, such as the trabecular structure. The trabecular bone score (TBS) of the lumbar spine can be measured by dual energy x-ray absorptiometry as a measure of trabecular structure and may reflect resistance to fracture beyond that of bone mineral alone. Thus, the aim of this study was to investigate whether TBS is lower in diabetes patients with a Charcot foot compared to diabetes patients without a Charcot foot, and to assess changes in TBS and occurrence of fractures over 8.5 years in these patients. Methods: 41 patients with type 1 or type 2 diabetes, of which about half had a Charcot foot, were included in 2005-2007 and 21 of these were followed up after 8.5 years. TBS and bone mineral density (BMD) of the lumbar spine were measured with Lunar Prodigy DXA-scanner and TBS iNsight software. The occurrence of bone fractures from baseline to follow-up was registered. Results: There were no significant differences in TBS between those with and those without a Charcot foot neither at baseline nor at follow-up (p>0.32). Furthermore, there was no significant change in TBS from baseline to follow-up in neither those with nor those without a Charcot foot (p>0.19), and there was no significant difference in the change in TBS between the two groups (p>0.21). All fractures had occurred in the diabetes patients with an acute Charcot foot (4 out of 10 patients at follow-up: i.e. 40%), which is statistically significant (p<0.035) compared to no fractures in the diabetes patients without a Charcot foot (11 patients at follow up). There were no significant associations between BMD, TBS, and biochemical markers of bone turn over at baseline and later occurrence of fracture in the diabetes patients with Charcot foot. Conclusion: There was no association of TBS of the lumbar spine and having a Charcot foot, or not, in diabetes patients, neither at baseline, nor after 8.5 years follows up. Diabetes patients with an acute Charcot foot seem to have an increased risk of fracture, which might not be revealed by measurement of TBS.