title: Evidence for simultaneous bidirectional fluid flux across synovial lining in knee joints of anaesthetized rabbits.
abstract: A recent model predicted a local synovial circulation of extravascular fluid in which capillary filtrate entered a joint cavity and fluid simultaneously drained out of the cavity via intercellular pathways distant from capillaries. Here, solutions of albumin (10-250 g l-1) were infused continuously into the knee joint cavity in fifteen anaesthetized rabbits at 3-18 cmH2O pressure and steady-state net trans-synovial flow was recorded. The intra-articular fluid collected after 15-30 min was substantially diluted despite a sustained net efflux from the cavity. This supports the prediction that net efflux comprises an influx of low-protein plasma ultrafiltrate and a larger efflux of joint fluid.
authors.affiliation: Department of Physiology, St George's Hospital Medical School, London.
authors.forename: J N
authors.initials: JN
authors.lastname: McDonald
authors.forename: J R
authors.initials: JR
authors.lastname: Levick
mesh_terms: D000418:Albumins / Q000493:pharmacokinetics; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D005260:Female; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D011817:Rabbits; D013582:Synovial Fluid / Q000502:physiology*; D013583:Synovial Membrane / Q000502:physiology*; D014474:Unconsciousness / Q000503:physiopathology*
chemical_list: D000418:Albumins