• Ronny Bindl, Ralf Oheim, Pia Pogoda, Frank Timo Beil, Katharina Gruchenberg, Sandra Reitmaier, Tim Wehner, Enrico Calcia, Peter Radermacher, Lutz Claes, Michael Amling, and Anita Ignatius.
• Institute of Orthopaedic Research and Biomechanics, Center of Musculoskeletal Research, University of Ulm, Helmholtzstr. 14, 89081, Ulm, Germany.
• J. Orthop. Res. 2013 Nov 1; 31 (11): 1851-7.

AbstractWe recently established a large animal model of osteoporosis in sheep using hypothalamic-pituitary disconnection (HPD). As central regulation is important for bone metabolism, HPD-sheep develop severe osteoporosis because of low bone turnover. In this study we investigated metaphyseal fracture healing in HPD-sheep. To elucidate potential pathomechanisms, we included a treatment group receiving thyroxine T4 and 17β-estradiol. Because clinically osteoporotic fractures often occur in the bone metaphysis, HPD-sheep and healthy controls received an osteotomy in the distal femoral condyle. Half of the HPD-sheep were systemically treated with thyroxine T4 and 17β-estradiol during the healing period. Fracture healing was evaluated after 8 weeks using pQCT, µCT, and histomorphometrical analysis. Bone mineral density (BMD) and bone volume/total volume (BV/TV) were considerably reduced by 30% and 36%, respectively, in the osteotomy gap of the HPD-sheep compared to healthy sheep. Histomorphometry also revealed a decreased amount of newly formed bone (-29%) and some remaining cartilage in the HPD-group, suggesting that HPD disturbed fracture healing. Thyroxine T4 and 17β-estradiol substitution considerably improved bone healing in the HPD-sheep. Our results indicate that fracture healing requires central regulation and that thyroxine T4 and 17β-estradiol contribute to the complex pathomechanisms of delayed metaphyseal bone healing in HPD-sheep.© 2013 Orthopaedic Research Society.

19 keywords...

hide…