Y. Kuriwaka et J. Ahlqvist, JOINT FLUID HYDROSTATIC PRESSURES THAT EMPTY SYNOVIAL CAPILLARIES OF RED-CELLS HAVE A WIDE-RANGE AND CORRELATE WITH PRESSURES EMPTYING ARTERIOLES, Journal of rheumatology, 25(7), 1998, pp. 1364-1368
Objective. To study if, as predicted by calculations based on 3 Starli
ng pressures, the fourth one, capillary pressure, may increase enough
to contribute to joint swelling. Methods. At magnifying arthroscopy, r
ed cells mostly flow separated from each other in capillaries and prec
apillary vessels (arterioles). These are emptied of erythrocytes at in
traarticular injection of saline to ''tamponade'' pressures. Patients
sent for arthroscopy of the knee joint for mechanical or other lesions
, or ''internal derangement'' (n = 30) or osteoarthritis (n = 26) were
studied. Results, The range of capillary (including postcapillary ven
ular) tamponade pressure was 9-70 mm Hg. It correlated (r = 0.536, p <
0.001) with arteriolar tamponade pressure (range 20-100 mm Hg). Concl
usion. If intravascular hydrostatic pressure is the main determinant o
f tamponade pressure, then increase of capillary pressure, possibly du
e to arteriolar dilatation induced precapillary pressure increase, may
be a key mechanism in enhanced formation of synovial fluid.