The biologic responses to orthopedic implants and their wear debris.

The use of artificial materials in the treatment of orthopaedic conditions, most notably arthritis, over the past few decades has been increasing dramatically. Such use makes an understanding of the tissue responses to the various materials necessary to determine their effectiveness and acceptability. This review concentrates on the studies of the biological responses to the materials that are used mainly in joint replacements and fixation of fractures. In-vivo and in-vitro experimental studies of various metals, polymers and ceramics and their constituents are first presented with discussions regarding their clinical importance. Studies of clinically successful implants are then presented to illustrate the expected morphological features of incorporation and acceptance by the host tissues. The local and systemic effects complicating the use of the implanted materials as well as the failure of the implant are then presented.