AAOS Now

Published 11/1/2011
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Annie C. Hayashi

The real story on MOM bearings

“The in-vivo longevity of contemporary hip implant systems can match the increased demands of both younger and senior patient populations,” said A. Seth Green-wald, DPhil (Oxon). In recent years, however, this widely heralded technology has come under scrutiny in both the peer-reviewed literature and press reports—particularly with regard to implant designs with metal-on-metal (MOM) bearings. Adverse local tissue reactions have led to less than optimal revision outcomes; hypersensitivity, metallosis, osteolysis, and pseudotumors have been associated with component failure.

To address basic questions such as “What is the actual extent of the problem?” and “What is the current clinical and basic science knowledge of these issues?” the Orthopaedic Research Society (ORS) will hold a workshop, “Metal-Metal Bearings: Facts, Fictions and Future,” on Tuesday morning, Feb. 7, 2012, during its 2012 annual meeting in San Francisco. Later that day, the “ORS/AAOS Combined Symposium I: Adverse Reactions to Byproducts of Joint Replacement” will review antigen-specific inflammatory responses to byproducts of joint replacement.

Getting the real story
According to Dr. Greenwald, one of three organizers of the ORS workshop, participants will gain an understanding of the extent of the MoM bearing problem.

“Recent reports have raised questions about biological reactions to MoM implants,” said workshop organizer Lynne C. Jones, PhD. “We need to carefully examine the materials and designs of the implants involved as well as patient and surgical factors.”

“We’ll examine the current status of the basic and clinical science,” said Warren O. Haggard, PhD, the third workshop organizer. “We’ll evaluate what is known and areas where we don’t have enough basic science or clinical evidence to make a decision.”

Among the speakers at the ORS workshop will be Stuart B. Goodman, MD, PhD, FRCS(C); Joshua J. Jacobs, MD; David W. Murray, MD, FRCS; Thomas W. Bauer, MD, PhD; and Steven M. Kurtz, PhD.

“Participants should gain an appreciation of the problems when they occur and learn to assess pathologies from both radiographic and histologic evaluations,” Dr. Greenwald concluded.

For more information on the 2012 ORS Annual Meeting, visit www.ors.org

Annie C. Hayashi is the ORS development and communications manager. She can be reached at hayashi@ors.org