SURGERY Adverse reactions to metal-on-metal implants

New data demonstrate that cobalt ions promote immune system activation through Toll-like receptor 4 signalling. This finding adds to our understanding of the adverse innate and adaptive immune reactions evoked by debris released from metal-on-metal total or resurfacing joint replacement implants, which have provoked recommendations against their use. Konttinen, Y. T. & Pajarinen, J. Nat. Rev. Rheumatol. 9, 5-6 (2013); published online 4 December 2012; doi:10.1038/nrrheum.2012.218