Bone mineral loss at the proximal femur in acute spinal cord injury
- 418 Downloads
This study used quantitative computed tomography to assess changes in bone mineral at the proximal femur after acute spinal cord injury (SCI). Individuals with acute SCI experienced a marked loss of bone mineral from a combination of trabecular and endocortical resorption. Targeted therapeutic interventions are thus warranted in this population.
SCI is associated with a rapid loss of bone mineral and an increased rate of fragility fracture. Some 10 to 20 % of these fractures occur at the proximal femur. The purpose of this study was to quantify changes to bone mineral, geometry, and measures of strength at the proximal femur in acute SCI.
Quantitative computed tomography analysis was performed on 13 subjects with acute SCI at serial time points separated by a mean of 3.5 months (range, 2.6–4.8 months). Changes in bone mineral content (BMC) and volumetric bone mineral density (vBMD) were quantified for integral, trabecular, and cortical bone at the femoral neck, trochanteric, and total proximal femur regions. Changes in bone volumes, cross-sectional areas, and surrogate measures of compressive and bending strength were also determined.
During the acute period of SCI, subjects experienced a 2.7–3.3 %/month reduction in integral BMC (p < 0.001) and a 2.5–3.1 %/month reduction in integral vBMD (p < 0.001). Trabecular BMC decreased by 3.1–4.7 %/month (p < 0.001) and trabecular vBMD by 2.8–4.4 %/month (p < 0.001). A 3.9–4.0 %/month reduction was observed for cortical BMC (p < 0.001), while the reduction in cortical vBMD was noticeably lower (0.8–1.0 %/month; p ≤ 0.01). Changes in bone volume and cross-sectional area suggested that cortical bone loss occurred primarily through endosteal resorption. Declines in bone mineral were associated with a 4.9–5.9 %/month reduction in surrogate measures of strength.
These data highlight the need for therapeutic interventions in this population that target both trabecular and endocortical bone mineral preservation.
KeywordsBone fracture Bone strength Densitometry Disuse osteoporosis QCT
- 5.Zehnder Y, Luthi M, Michel D, Knecht H, Perrelet R, Neto I, Kraenzlin M, Zach G, Lippuner K (2004) Long-term changes in bone metabolism, bone mineral density, quantitative ultrasound parameters, and fracture incidence after spinal cord injury: a cross-sectional observational study in 100 paraplegic men. Osteoporos Int 15:180–189. doi:10.1007/s00198-003-1529-6 PubMedCrossRefGoogle Scholar
- 13.Black DM, Delmas PD, Eastell R, Reid IR, Boonen S, Cauley JA, Cosman F, Lakatos P, Leung PC, Man Z, Mautalen C, Mesenbrink P, Hu H, Caminis J, Tong K, Rosario-Jansen T, Krasnow J, Hue TF, Sellmeyer D, Eriksen EF, Cummings SR, Pivotal Fracture Trial HORIZON (2007) Once-yearly zoledronic acid for treatment of postmenopausal osteoporosis. N Engl J Med 356:1809–1822. doi:10.1056/NEJMoa067312 PubMedCrossRefGoogle Scholar
- 14.Cummings SR, San Martin J, McClung MR, Siris ES, Eastell R, Reid IR, Delmas P, Zoog HB, Austin M, Wang A, Kutilek S, Adami S, Zanchetta J, Libanati C, Siddhanti S, Christiansen C, Trial FREEDOM (2009) Denosumab for prevention of fractures in postmenopausal women with osteoporosis. N Engl J Med 361:756–765. doi:10.1056/NEJMoa0809493 PubMedCrossRefGoogle Scholar
- 21.Bousson V, Le Bras A, Roqueplan F, Kang Y, Mitton D, Kolta S, Bergot C, Skalli W, Vicaut E, Kalender W, Engelke K, Laredo JD (2006) Volumetric quantitative computed tomography of the proximal femur: relationships linking geometric and densitometric variables to bone strength. Role for compact bone. Osteoporos Int 17:855–864. doi:10.1007/s00198-006-0074-5 PubMedCrossRefGoogle Scholar
- 23.Keaveny TM, Hoffmann PF, Singh M, Palermo L, Bilezikian JP, Greenspan SL, Black DM (2008) Femoral bone strength and its relation to cortical and trabecular changes after treatment with PTH, alendronate, and their combination as assessed by finite element analysis of quantitative CT scans. J Bone Miner Res 23:1974–1982. doi:10.1359/jbmr.080805 PubMedCrossRefGoogle Scholar
- 34.Ausk BJ, Gross TS (2012) Metaphyseal and diaphyseal bone loss following transient muscle paralysis are distinct osteoclastogenic events. Proceedings of the American Society of Biomechanics 36th Annual Meeting; 2012 Aug 15–18, Gainesville, FL. http://www.asbweb.org/conferences/2012/abstracts/200.pdf
- 38.Centers for Disease Control and Prevention (2010) Spinal cord injury (SCI): fact sheet. 2012Google Scholar
- 41.Giangregorio LM, Webber CE, Phillips SM, Hicks AL, Craven BC, Bugaresti JM, McCartney N (2006) Can body weight supported treadmill training increase bone mass and reverse muscle atrophy in individuals with chronic incomplete spinal cord injury? Appl Physiol Nutr Metab 31:283–291. doi:10.1139/h05-036 PubMedCrossRefGoogle Scholar
- 44.Cusick T, Chen CM, Pennypacker BL, Pickarski M, Kimmel DB, Scott BB, le Duong T (2012) Odanacatib treatment increases hip bone mass and cortical thickness by preserving endocortical bone formation and stimulating periosteal bone formation in the ovariectomized adult rhesus monkey. J Bone Miner Res 27:524–537. doi:10.1002/jbmr.1477 PubMedCrossRefGoogle Scholar