Effects of exercise on blood flow to canine articular tissues

We measured articular blood flow by standard microsphere techniques in normal adult dogs at rest and during treadmill exercise. All animals but one underwent beta-adrenergic blockade as part of another experimental protocol. Expressed in microliter/min/g +/- SEM, baseline flow values to articular tissues were: knee synovium 26 +/- 4, femoral condyle 130 +/- 21, tibial plateau 182 +/- 29, articular fat pad 9 +/- 2, knee ligaments 17 +/- 3, menisci 34 +/- 6, wrist synovium 19 +/- 4, distal radius 65 +/- 13, and lunate bone 59 +/- 13. Blood flow increased with exercise in all soft tissues of both the knee (stifle joint) and the wrist (radiocarpal joint). Geometric mean exercise/rest flow ratios ranged from a low of 1.44 (p less than 0.05) in the menisci of the knee to a high of 7.25 (p less than 0.001) in the synovium of the wrist. In contrast, blood flow did not rise in juxtaarticular bones and fell significantly in femoral condyles (mean flow ration 0.71, p less than 0.005). These findings indicate that articular soft tissues derive increased perfusion from the redistribution of blood flow that accompanies short-term exercise. In contrast, flow to juxtaarticular bone does not increase under these conditions.