Metallic Biomaterials in Orthopedic Surgery

Abstract

AbstractMetals have the longest history in the field of orthopedic surgery among numerous biomaterials. Metallic implants were used for the first time to fix spine fractures more than 100 years ago. Since then, metallic orthopedic implants were used routinely for fixation of bone fractures and deformity correction of the spine and long bones. The advantages of metals are excellent mechanical stiffness and fracture toughness to provide unstable fracture sites with sufficient stability to achieve biological bony union. Clinically used metals are stainless steel, Co-Cr (cobalt-chrome), and titanium alloys. The common indications of metallic implants for orthopedic surgery are fixation of bony fractures at different parts of the body, joint replacement, and deformity correction of long bones and the spinal column. Metallic implants are often removed at postoperative 1 or 2 years, after complete bony union is obtained, in order to prevent osteopenia or osteoporosis related to a stress-shielding effect around the location of the metallic implant. Future modification of the mechanical stiffness of metals may reduce the risk of stress-shielding effect. Also, biocompatible or osteoconductive metallic implants would be of significant clinical value with a longer survival of the artificial joint prosthesis. Many new technologies of surface modifications for metallic joint prosthesis have been invented to obtain direct bonding between the bone and metallic prosthesis for longer survival of prostheses. As the elderly population shows a significant increase around the globe, the demand for metallic orthopedic implants to maintain their quality of life has been expanding in recent years.KeywordsOrthopedic surgeryFracture fixationJoint replacementSpinal reconstructionBone ingrowthStress shieldingImplant looseningBiocompatibilityBone union