The role of osmic acid in the treatment of immune synovitis.

Thirty-seven New Zealand rabbits were observed for up to 1 year after their knee joints were instilled with 1 ml of 1% osmic acid. A selective destruction of synovial lining cells occurred with a concurrent synovitis, but lining cell regenerated by the eighth week. Nonprogressive abnormalities were also present in the cartilage. When an immune synovitis was induced in both knees of 16 rabbits, the osmic acid treated joint demonstrated a significantly greater synovitis and progressive aberrations compared to the untreated knee.