Rigid internal fixation with metallic plates is common practice in maxillofacial and orthopaedic bone surgery. However, metallic plates often have to be removed surgically due to problems related with stress shielding, soft tissue reactions, cosmesis and interference with radiation treatment. This second surgery causes increased patient morbidity as well as an increase in health care costs. The long term objectives of this research are to develop a polymeric, fully biodegradable fracture plate (BFP) for hard tissue fixation. Also, magnetic resonance imaging techniques will be developed to image the BFP in-vivo and monitor its biodegradation. The proposed study intends to accomplish the following specific aims: I. Development and mechanical evaluation of a polymeric BFP with the desired properties. Different design parameters will be manipulated to attain an optimum combination. Prototypes of a BFP have already been successfully fabricated in our laboratory. II. In-vitro evaluation of the BFP to establish its viability over an extended period of time. The mechanical and physical properties of the BFP will be characterized as a, function of biodegradation time. MRI techniques will be used to monitor the in-vitro biodegradation by hydrolysis. III. In-vivo evaluation of the BFP in a rabbit model to establish its potential as a fracture fixation device. MRI techniques will be developed to image the BFP in-vivo and monitor its biodegradation. Histological analysis will be performed post-sacrifice to assess the extent of bone repair and the effect of the biodegrading material on the surrounding tissue. These studies will lay the foundation for a new generation of fracture fixation plates.
