Citation

Bemben DA, Sherk VD, Ertl WJ, Bemben MG. Osteoporos. Int. 2017; 28(7): 2177-2186.

Affiliation

Bone Density Research Laboratory, Department of Health and Exercise Science, University of Oklahoma, 1401 Asp Avenue, Norman, OK, 73019, USA.

Copyright

(Copyright © 2017, Holtzbrinck Springer Nature Publishing Group)

DOI

10.1007/s00198-017-4018-z

PMID

28365850

Abstract

Bone health is critical for lower limb amputees, affecting their ability to use a prosthesis and their risk of osteoporosis. We found large losses in hip bone mineral density (BMD) and in amputated bone strength in the first year of prosthesis use, suggesting a need for load bearing interventions early post-amputation.

INTRODUCTION: Large deficits in hip areal BMD (aBMD) and residual limb volumetric BMD (vBMD) occur after lower limb amputation; however, the time course of these bone quality changes is unknown. The purpose of this study was to quantify changes in the amputated bone that occur during the early stages post-amputation.

METHODS: Eight traumatic unilateral amputees (23-53 years) were enrolled prior to surgery. Changes in total body, hip, and spine aBMD (dual-energy X-ray absorptiometry); in vBMD, stress-strain index (SSI), and muscle cross-sectional area (MCSA) (peripheral QCT); and in bone turnover markers were assessed after amputation prior to prosthesis fitting (pre-ambulatory) and at 6 and 12 months walking with prosthesis.

RESULTS: Hip aBMD of the amputated limb decreased 11-15%, which persisted through 12 months. The amputated bone had decreases (p < 0.01) in BMC (-26%), vBMD (-21%), and SSI (-25%) from pre-ambulatory to 6 months on a prosthesis, which was maintained between 6 and 12 months. There was a decrease (p < 0.05) in the proportion of bone >650 mg/cm(3) (58 to 43% of total area) or >480 mg/cm(3) (65% to 53%), suggesting an increase in cortical porosity after amputation. Bone alkaline phosphatase and sclerostin were elevated (p < 0.05) at pre-ambulatory and then decreased towards baseline. Bone resorption markers were highest at surgery and pre-ambulatory and then progressively decreased (p < 0.05).

CONCLUSIONS: Rapid and substantial losses in bone content and strength occur early after amputation and are not regained by 12 months of becoming ambulatory. Early post-amputation may be the most critical window for preventing bone loss.

Language: en

Keywords

Bone density; Bone geometry; Bone remodeling; Prosthesis; Trauma