Metal-on-Metal Bearing: Is This the End of the Line? We Do Not Think So

Henri Migaud, MD
Department of Orthopaedic Surgery, Roger Salengro Hospital, Orthopaedics Department, University of Lille, France

Sophie Putman, MD
Department of Orthopaedic Surgery, Roger Salengro Hospital, Orthopaedics Department, University of Lille, France

Antoine Combes, MD
Department of Orthopaedic Surgery, Roger Salengro Hospital, Orthopaedics Department, University of Lille, France

Charles Berton, MD
Department of Orthopaedic Surgery, Roger Salengro Hospital, Orthopaedics Department, University of Lille, France

Donatien Bocquet, MD
Department of Orthopaedic Surgery, Roger Salengro Hospital, Orthopaedics Department, University of Lille, France

Laurent Vasseur, MD
Department of Orthopaedic Surgery, Roger Salengro Hospital, Orthopaedics Department, University of Lille, France

Julien Girard, PhD, MD
Department of Orthopaedic Surgery, Roger Salengro Hospital, Department of Sport and Medicine, Orthopaedics Department, University of Lille, France


Abstract

Background: 
Recent studies have recommended the discontinuation of metal-on-metal (MoM) components in total hip arthroplasty (THA) because of adverse effects reported with large-diameter MoM THA. This is despite favorable long-term results observed with 28 and 32 mm MoM bearings.

Questions/purposes: 
The aim of this study was to assess the value of calls for an end to MoM bearings as THA components. Specifically, we wish to address the risks associated with MoM bearings including adverse soft tissue reactions, metal ion release, and carcinogenic risk.

Methods: 
The study evaluates the arguments in the literature reporting on MoM (adverse soft tissue reactions, metal ion release, and carcinogenic risk) and the experience of the current authors who re-introduced these bearings in 1995. They are balanced by a benefit–risk review of the literature and the authors’ experience with MoM use.

Results: 
Adverse reactions to metallic debris as well as metal ion release are predictable and can be prevented by adequate design (arc of coverage, clearance), metallurgy (forged instead of cast alloy, high-carbide content), and appropriate component orientation. There is no scientific evidence that carcinogenicity is increased in subjects with MoM hip prostheses. MoM articulations appear to be attractive allowing safe hip resurfacing, decreasing the risk of THA revision in active patients, and providing secure THA fixation with cement in cages in severely deformed hips. MoM bearings in women of child-bearing age are controversial, but long-term data on metallic devices in adolescents undergoing spinal surgery seem reassuring.

Discussion: 
Adequate selection of MoM articulations ensures their safe use. These articulations are sensitive to orientation. Fifteen years of safe experience with 28- and 32-mm bearings of forged alloy and high-carbide content is the main reason for retaining them in primary and revision THA.

This article appears in HSS Journal: Volume 8, Number 3.
View the full article at springerlink.com.

About the HSS Journal

HSS Journal, an academic peer-reviewed journal published three times a year, February, July and October. The Journal accepts and publishes peer reviewed articles from around the world that contribute to the advancement of the knowledge of musculoskeletal diseases and disorders.

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