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    ASBMR 2010 Annual Meeting

    Teriparatide Treatment of Osteoporotic Women Increases Cortical Bone at Critical Sites in the Proximal Femur: An In Vivo Study using High Resolution Cortical Thickness Mapping

    Categories:
     Osteoporosis - Treatment (Clinical)
     Bone Biomechanics and Quality (Clinical)

    Oral Presentations, Presentation Number: 1250
    Session: Concurrent Oral Session 42: Osteoporosis Treatment: Pharmacologic and Non-Pharmacologic
    Monday, October 18, 2010 5:15 PM - 5:30 PM, Metro Toronto Convention Centre, South Building, South Building: Hall G

    Andrew H Gee, University of Cambridge, United Kingdom, Graham M Treece, University of Cambridge, United Kingdom, Paul Mayhew, University of Cambridge, UNITED KINGDOM, Jan Borggrefe, University of Schleswig-Holstein, Germany, * Kenneth Poole, University of Cambridge, UNITED KINGDOM

    Teriparatide treatment of osteoporotic women improved hip bone structure, most likely due to endocortical apposition of new bone since there was no associated increase in periosteal size (Borggrefe et al, JBMR in press). Teriparatide may enhance bone strength by increasing the sensitivity to load stimuli, but evidence for this effect in humans is lacking. In this study, we sought to identify the precise location of teriparatide-stimulated cortical bone growth in the human proximal femur. Women with severe osteoporosis were treated with teriparatide (the EUROFORS study) for 24 months, with QCT scans of the hips performed at baseline, 12 and 24 months. A novel cortical thickness mapping technique (Treece et al, Medical Image Analysis in press) was used to evaluate both proximal femurs of 65 qualifying QCT participants at baseline and 24 months. The surface of each femur was segmented from the CT scans using a semi-automated technique (119 femurs in total, 11 excluded mainly due to metalwork artefacts). This surface was used to automatically guide approximately 7,000 independent measurements of cortical thickness over the femur. Cortical thickness estimates were mapped to a canonical femur surface by non-rigid registration of the 119 femurs. Statistical parametric mapping (SPM) was used to identify significant changes in cortical thickness over time, displayed as a colour map over the canonical femur surface (figure, which shows statistically significant vertices and clusters). Cortical thickness increased significantly at several sites but did not decrease significantly anywhere. Zones that receive a high compressive stress during normal locomotion demonstrated a significant (p<0.01) increase in cortical thickness (0.05-0.2mm): the infero-medial cortex, and a posterior inter-trochanteric site where the calcar femorale transmits load from the trabeculae to the cortex. Several sites thought to be under tensile stress during locomotion were significantly thicker after teriparatide: on the greater and lesser trochanters near the attachment sites of the gluteus medius and psoas respectively. Thickness also increased at the head-neck junction of the superior cortex. We conclude that teriparatide treatment for 24 months increases cortical bone thickness at sites of compressive stress during locomotion, near key muscle attachments and in the superior cortex, considered critical for hip fracture susceptibility.

    Disclosures: None

    * Presenting Authors(s): Kenneth Poole, University of Cambridge, UNITED KINGDOM

    Attachments

    Maps of cortical thickness change (excluding the femoral head) and significance