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Journal of Bone and Joint Surgery - British Volume, Vol 85-B, Issue 1,
133-141.
doi: 10.1302/0301-620X.85B1.12749 Copyright © 2003 by British Editorial Society of Bone and Joint Surgery Microvascular response of striated muscle to metal debrisA COMPARATIVE IN VIVO STUDY WITH TITANIUM AND STAINLESS STEELC. N. Kraft, MD, Resident; O. Diedrich, MD, Resident; B. Burian, Research Student; and O. Schmitt, MD, Professor and ChairmanDepartment of Orthopaedic Surgery, University of Bonn, Sigmund Freud Strasse 25, D-53105 Bonn, Germany. M. A. Wimmer, PhD, Grouphead Joint Replacement Rush-Presbyterian St Lukes Medical Centre, Chicago, Illinois 60612, USA. AO Research Institute, Clavadelerstrasse, CH-7270 Davos, Switzerland. Correspondence should be sent to Dr C. N. Kraft. Wear products of metal implants are known to induce biological events which may have profound consequences for the microcirculation of skeletal muscle. Using the skinfold chamber model and intravital microscopy we assessed microcirculatory parameters in skeletal muscle after confrontation with titanium and stainless-steel wear debris, comparing the results with those of bulk materials. Implantation of stainless-steel bulk and debris led to a distinct activation of leukocytes combined with a disruption of the microvascular endothelial integrity and massive leukocyte extravasation. While animals with bulk stainless steel showed a tendency to recuperation, stainless-steel wear debris induced such severe inflammation and massive oedema that the microcirculation broke down within 24 hours after implantation. Titanium bulk caused only a transient increase in leukocyte-endothelial cell interaction within the first 120 minutes and no significant change in macromolecular leakage, leukocyte extravasation or venular diameter. Titanium wear debris produced a markedly lower inflammatory reaction than stainless-steel bulk, indicating that a general benefit of bulk versus debris could not be claimed. Depending on its constituents, wear debris is capable of eliciting acute inflammation which may result in endothelial damage and subsequent failure of microperfusion. Our results indicate that not only the bulk properties of orthopaedic implants but also the microcirculatory implications of inevitable wear debris play a pivotal role in determining the biocompatibility of an implant.
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