Resorption of intraarticular diffusible and microcolloid tracers: Rabbit studies of normal and synovitic knees

Abstract

The resorption of two radiotracers (99mtechnetiumlabeled microcolloid particles to study lymphatic transport and 51chromium-EDTA to study diffusion) from the knee joint and the subcutaneous tissue of rabbits was investigated simultaneously. In 12 rabbits, synovitis was induced in the right knee 6 weeks or 3 months before the investigation; 6 rabbits served as controls. The final number of Tcparticles in the normal knees and in the sub-cutaneous tissue in the three groups did not differ; but removal from the synovitic knees was increased. The final number of Cr-EDTA particles did not differ within or between groups. The initial decrease was highest in the knees with acute synovitis (P < 0.05). The results indicate (1) that in synovial tissue lymphatic transport is of little importance, (2) that leakage through the synovial membrane increases in synovitis, and (3) that a subcutaneous depot can be used as a reference instead of injections into a normal knee.