A Simple Critical-sized Femoral Defect Model in XXXX .

@entity1 @entity174 @entity19 @entity79 @entity2100 @entity35 @entity130
UNASSIGNED: While bone has a remarkable capacity for regeneration, serious bone @entity130 often results in damage that does not properly heal. In fact, one tenth of all limb @entity174 fail to heal completely due to the extent of the @entity130 , disease, or age of the @entity1 . Our ability to improve bone regenerative strategies is critically dependent on the ability to mimic serious bone @entity130 in test animals, but the generation and stabilization of large @entity79 is technically challenging. In most cases, serious long bone @entity130 is mimicked experimentally by establishing a defect that will not naturally heal. This is achieved by complete removal of a bone segment that is larger than 1.5 times the diameter of the bone cross-section. The bone is then stabilized with a metal implant to maintain proper orientation of the @entity174 edges and allow for mobility. Due to their small size and the @entity2100 of their long bones, establishment of such lesions in @entity19 are beyond the capabilities of most research groups. As such, long @entity79 models are confined to @entity35 and larger animals. Nevertheless, @entity19 afford significant research advantages in that they can be genetically modified and bred as immune-compromised strains that do not reject @entity1 cells and tissue. Herein, we demonstrate a technique that facilitates the generation of a segmental defect in @entity19 femora using standard laboratory and veterinary equipment. With practice, fabrication of the fixation device and surgical implantation is feasible for the majority of trained veterinarians and animal research personnel. Using example data, we also provide methodologies for the quantitative analysis of bone healing for the model.
