| Title | Improvements in Vertebral Body Strength under Teriparatide Treatment Assessed In Vivo by Finite Element Analysis: Results from the EUROFORS Study. | | Author(s) | Graeff C, Chevalier Y, Charlebois M, Varga P, Pahr D, Nickelsen TN, Morlock MM, Glüer CC, Zysset PK | | Source | J Bone Miner Res 2009 May 6. | | Abstract | Abstract Monitoring of osteoporosis therapy based solely on Dual Energy X-ray Absorptiometry (DXA) is insufficient to assess anti-fracture efficacy. Estimating bone strength as a variable closely linked to fracture risk is therefore of importance. Finite Element (FE) Analysis based strength measures were used to monitor a teriparatide therapy and the associated effects on whole bone and local fracture risk. In 44 postmenopausal women with established osteoporosis participating in the EUROFORS study, FE models based on High-Resolution Computed Tomography (HRCT) of T12 were evaluated after 0, 6, 12, and 24 months of teriparatide treatment (20 mug/day). FE based strength and stiffness calculations for three different load cases (compression, bending, and combined compression and bending) were compared to volumetric bone mineral density (vBMD) and apparent bone volume fraction (app. BV/TV) as well as DXA based areal BMD of the lumbar spine. Local damage of the bone tissue was also modeled. Highly significant improvements in all analyzed variables as early as 6 months after starting teriparatide were found. After 24 months, bone strength in compression was increased by 28.1 +/- 4.7 % (mean +/- SEM), in bending by 28.3 +/- 4.9 %, while app. BV/TV was increased by 54.7 +/- 8.8 %, vBMD by 19.1 +/- 4.0 %, and areal BMD of L1-L4 by 10.2 +/- 1.2 %. When comparing standardized increases, FE changes were significantly larger than those of densitometry and not significantly different from app. BV/TV. The size of regions at high risk for local failure was significantly reduced under teriparatide treatment. Treatment with teriparatide leads to bone strength increases for different loading conditions of close to 30 %. FE is a suitable tool for monitoring bone anabolic treatment in groups or individual patients and offers additional information about local failure modes. FE variables showed a higher standardized response to changes than bone mineral density measurements, but further studies are required to show that the higher response represents a more accurate estimate of treatment-induced fracture risk reduction. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19419306 |
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