Recent developments in the tribology of artificial joints

A history of the tribological development of artificial joints compares how these are lubricated with the mechanisms involved in human joints. It is concluded that while healthy human joints are lubricated by fluid film action, all current artificial joints at best are lubricated by mixed lubrication and hence wear is taking place throughout the life of the prosthesis. A new concept in artificial joints is described. Soft elastic layers simulate articular cartilage and if selected carefully can develop full fluid film lubrication with consequential low friction and minimal wear.