13th International Conference on Fracture June 16–21, 2013, Beijing, China -3- Figure 1. Sketch of the fracture healing progress throughout the study [1] Figure 2. Gap measurement and scale verification 2.2 Four Point Bending Test (4PBT) The bones were cleaned to remove any excess of cartilage or ligaments. Figure 3a shows the process by using a saw, a mechanical clamp and protective wrapping, to prevent any damage to the sample. Once the bone extremities had been removed (Figure 3b) they were conserved for UMI testing. a) b) Figure 3. a) Removal of bone upper extremity during sample preparation and b) final aspect The samples were tested within 24 hours of the bone extraction to obtain the most accurate results possible. Before each test the bones were preheated to 37ºC in a saline solution to replicate the temperature in the bone’s usual environment. 4PBTs were carried out on the diaphysis (shaft of the bone) using an universal testing machine (0.5 class). The sample was placed within a methacrylate container, and a water bath was set to 37°C. A pump was then positioned so that the heated serum could flow around the sample, thus recreating the in vivo conditions. Figure 4a displays the main elements of the installation.
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