ABSTRACT
Due to the complicated nature, bone defects caused by various conditions have been challenging orthopaedic surgeons and related biomedical scientists for some time, and are continuing to inspire them to seek better alternatives and new solutions. To achieve their goals, animal models of bone defects for bone grafting are essential. There are several major heterotopic models for testing in vivo osteogenesis, the subcutaneous model, the intramuscular model, the intraperitoneal model, and the mesentery model. The rabbit radial model is popular because the radius bone is tubular, which allows creation of a segmental defect that enables convenient radiographic and histological evaluation. A rabbit ulnar defect is also popular, but the ulnae do not have the round shape as the radius, which creates difficulties and errors to the processes of implant preparation, implant positioning, and sample evaluation. For long bone segmental defect models, torsional testing is an appropriate and the most popular method.
