Robert Stefani publishes a novel in vitro tissue engineered synovium model, validated against native explants, to investigate the structure-function of synovium through quantitative solute transport measures. The synovium envelops the diarthrodial joint and plays a key regulatory role in defining the composition of the synovial fluid through filtration and biosynthesis of critical boundary lubricants. Synovium changes often precede cartilage damage in osteoarthritis, but the mechanism by which it may contribute to disease progression has not yet been elucidated. It is anticipated that this model will support efforts to develop more effective strategies aimed at restoring joint health.