Totally Biodegradable Implants for Bone Fixation and Ligament Repair

Synthetic biomaterials can be divided into metals, polymers, ceramics, and composites. Polymeric biomaterials and composites can be classified as biostable, partially biodegradable, or totally biodegradable. Biostable polymers are inert, cause minimal tissue response, and retain their properties for years. Because only a temporary supporting biomaterial is required in many clinical applications, totally or partially biodegradable polymeric materials are often better than biologically biostable materials. Biodegradation implies the degradation of a material induced by the activities of an organism, but it is also influenced by pure physicochemical reactions. Degradable polymeric or composite materials retain their support from days to months, depending on their properties. They are biologically degraded, gradually, into tissue-compatible components that are absorbed, used in the organism, and finally secreted by the normal ways. Biodegradable materials are the best choice for internal fixation of fractures because the biodegradable implant provides and maintains the required fixation during the healing process. It decomposes gradually and transfers the stresses increasingly to the healing bone, thus avoiding stress-shielding. Micromovement at the fracture and correction of the bone-mass decrease are possible, too. After healing, when absorbed, the device can be utilized in energy and protein metabolism. Implanted biodegradable devices do not require a removal operation, which is a financial and psychological benefit to the patient.