No abstract

1. The rate of disappearance of intra-articularly administered 133Xe from the knee joint was studied in normal subjects and in patients suffering from various arthritides. The disappearance curve was monoexponential and could be described by a biological half life . The half lives were shown to be reproducible, but could be reduced marginally by aspirating knee joint effusion when present. 2. It was demonstrated that the values depended, not upon the pathological diagnosis, but upon the degree of inflammatory involvement of the knee joint at the time of study. 3. The effect of intra-articularly administered hydrocortisone upon the value was investigated in twenty-five rheumatoid subjects. The mean value obtained before injection of hydrocortisone was significantly lower than the mean value obtained 24 hr later. Significant clinical improvement was also noted. The relationship between individual clinical improvement and the change in value was examined.

Desmosomes or desmosome-like structures do not occur between normal synovial cells but such structures do develop between the synovial cells in cases of traumatic arthritis, rheumatoid arthritis and villonodular synovitis. Morphological evidence is presented suggesting that such structures develop as a result of the interaction of fibrin trapped between synovial cells and the plasmamembrane of these cells.

Synovial blood flow in the stiffle joint of the dog was determined by an inert gas clearance technique.