The diffusion of nine commonly used antibiotics into traumatically inflamed human knees was studied in fifty young men. The antibiotic level in the synovial fluid was found to approximate that in the blood. There was a suggestion that a correlation existed between diffusibility and the molecular weight of the antibiotic tested, as previously reported10,15. The free diffusibility of antibiotics into traumatically inflamed human joints was demonstrated.
Therapeutic effectiveness should correlate better with the antibacterial activity obtained in the joint fluid than with the concentration of the antibiotic in micrograms per unit volume of synovial fluid.