Understanding how bone grows (remodels) about permanent implants such as artificial knees and hips is critical to their success. Bone loss and subsequent implant loosening is the primary cause of implant failure. Once an implant fails, a patient must have it removed and another put in its place. It has been reported that as many as 10% of all hip prostheses fail after 10 years of implantation and up to 20% fail at 15 years. Revisions fail at a greater rate than primary implants because much of the bone has been lost. For the 30 year old rheumatoid arthritic patient, this means that by the age of 50 he or she may have had multiple joint replacement procedures and could well be wheelchair bound or bed ridden.

Our laboratory is committed to the understanding of how bone remodels about total joint prostheses, the investigation of new high technology materials for the prosthesis itself, as well as superior coatings and surfaces for implant attachment to bone. Three areas of research that are carried on in this laboratory include: scanning acoustic microscopy to evaluate bone remodeling, bioceramic coatings and materials for improved bone response, and clinical studies involving total knee and hip prosthesis. The laboratory is investigating novel ways of evaluating how bone remodels about implants. Scanning acoustic microscopy is a microscopic technique that is presently used in the aerospace industry to determine the quality of parts fabricated for high technology aircraft and space vehicles. This technique can also be used to evaluate the quality of bone that has remodeled about orthopaedic implants. Other standard histological techniques provide qualitative information such as volume or area of bone adjacent to an implant, however, the acoustic technique provides detailed quantitative information regarding the actual properties of the bone on a microscopic scale. This extraordinary new concept involves a collaborative effort with U.S. industry and an international academic group (Laboratoire de Recherches Orthopediques, Faculte de Medecine Lariboisiere-Saint-Louis, Paris France). The surface of total joint implants is a key parameter regarding their success. Porous metal coatings have been used to encourage bone ingrowth and attachment to the implant.

More recently, high-performance bioceramics that encourage bone attachment have become a very active area of research throughout the United States and in the world. Clinical studies have demonstrated short term advantages of these materials for bone attachment, however, little is known about the long term effectiveness of these materials in the body. A number of studies in this laboratory have been initiated to investigate newly developed innovative ceramic coatings and their effect on tissues in the body as well as the environment effect of implantation on the materials.

Finally, clinical investigators associated with the laboratory are assessing the efficacy of devices presently implanted in patients. This activity involves the design of studies, the ongoing evaluation of patient progress, collecting and collating data, and publishing papers in peer reviewed journals and books. Although extremely time consuming and tedious, this is a critical area of research. Surgeons and researchers must understand the clinical problems of present day implants in order to design superior implants of the future.