Development of Early Concepts of Lubrication in Natural Synovial Joints

Despite a significant increase in the number of lubrication studies of articualr cartilage and synovial joints in recent times, the early development of lubrication concepts is particularly important and has played an important role in the understanding of the complex lubrication mechanism in these natural bearings. The majority of the important lubrication concepts were developed before 1970s. The aim of this paper is to present a record of early major lubrication concepts developed for natural synovial joints up to the 1970s; to present a few selected recent studies to interpret the results and contradictions and to highlight the importance of a systematical approach and reinforce the concept of the multi-mode lubrication. Some recently proposed, unique lubrication mechanisms for the natural synovial joints are also discussed.