| Outcome Measures: |
Primary: Finite element analysis of bone to measure bone strength, The FEA (or FEA) is a surrogate measure of strength using computational biomechanical principles and integrate bone morphology and bone mass to calculate bone strength under various loading conditions normally seen in daily living activities. In addition, the ratio of load to strength can be calculated by using patient information (i.e. weight and height) and FEA derived bone strength to mechanistically simulate bone failure and thus, whether fracture is likely during a given activity. Using high-resolution peripheral quantitative computer tomography we will compute for FEA, using finite element analysis software with images generated using Image Processing Language to estimate the biomechanical properties of the bone. Each bone voxel will be converted to hexahedral finite elements with linear-elastic and isotropic material behavior. The FEA model will be subject to uniaxial compression and stiffness and failure load will be estimated. FEA will be assessed at months 0, 6 and 12., 5 years | Secondary: Markers of bone turnover to measure bone metabolism, Two markers of bone resorption, serum C-telopeptide (CTX) and tartrate-resistant acid phosphatase 5b (TRAP5b) and 2 markers of bone formation osteocalcin (OCN) and N-terminal propeptide of type 1 collagen (P1NP) will be evaluated. These markers will be obtained at months 0, 6, and 12. Enzyme-linked immunosorbent assay will be used to measure serum CTX (serum crosslaps, Osteometer, Hawthorne, CA), tartrate-resistant acid phosphatase 5b (TRAP5b) (EIA) (Microvue Bonehealth, Quidel Corporation, Biosource); and serum osteocalcin (ALPCO, Salem, NH). Serum P1NP will be measured by competitive radioimmunoassay (UniqTM P1NP RIA, Immunodiagnostic Systems, Scottsdale, AZ). Coefficients of variations for these assays are \<10%., 5 years|Osteoblast and osteoclast progenitor cells which are cells found in bone, Osteoblast and osteoclast progenitor cells will be harvested from the serum at baseline, 6 and 12 months., 5 years
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