Biomechanical evaluation of healing in a non-critical defect in a large animal model of XXXX .

@entity3604 @entity742 @entity174 @entity170 @entity79
Current methods for @entity174 treatment in @entity170 are not always sufficient. To develop new fixation strategies (both mechanical and biological) requires pre-clinical testing utilizing appropriate models. The aim of this study was to apply a recently developed @entity742 model of @entity170 to the study of healing in a @entity79 . A standardized transverse mid-shaft tibial osteotomy (with a @entity174 gap of 3 mm) was performed in seven @entity3604 and seven normal @entity742 and stabilized with a special external fixator for 8 weeks. The fixator was used for weekly in vivo bending stiffness measurements. Ex vivo bending stiffness and torsional stiffness of the callus zone were also determined. Callus area, callus density, and @entity170 status were determined at 0, 4, and 8 weeks using peripheral quantitative computed tomography. The increase of in vivo bending stiffness of the callus was delayed approximately 2 weeks in @entity3604 . A significant difference (33%) in torsional stiffness was found between the osteotomized and contralateral intact tibia in @entity3604 , but no significant difference occurred in normal @entity742 (2%). In @entity3604 , ex vivo bending stiffness was reduced 21% (p=0.05). Bending stiffness was correlated with callus density (r=0.76, r=0.53); torsional stiffness was correlated with callus area (r=0.60) and to a lesser extent with callus density (r=0.53). This study demonstrated a delay of @entity174 healing in @entity3604 @entity742 tibiae with respect to callus formation, mineralization, and mechanical properties.
