Biomaterials in Orthopaedics: Definition and Basic Classification
Biomaterials are natural or synthetic materials designed to interact with biological tissues, fluids, or systems for diagnosis, treatment, augmentation, repair, or replacement of musculoskeletal structures. In orthopaedics they are used in fracture fixation, joint replacement, spinal surgery, ligament reconstruction, bone grafting, dental and craniofacial procedures, and external or implantable medical devices.
An orthopaedic biomaterial must not be considered merely as a mechanically strong substance. Its clinical performance depends on the interaction between its mechanical behaviour, surface properties, chemical stability, tissue response, manufacturing method, sterilisation, and design. The same material may be satisfactory in one application and unsuitable in another; for example, a material suitable for a temporary fracture plate may not be appropriate for a permanent joint-bearing surface.
Essential Requirements of an Orthopaedic Biomaterial
- Biocompatibility: It should produce an acceptable local and systemic biological response. Absolute biological inertness is uncommon; the clinically relevant requirement is an appropriate and predictable tissue response.
- Mechanical competence: It should possess adequate strength, stiffness, fatigue resistance, toughness, wear resistance, and resistance to deformation for the intended anatomical site.
- Corrosion and chemical resistance: It should resist degradation in body fluids or degrade at a controlled rate when biodegradation…