Protection of cartilage in chemical synovectomy by perfusion.

The authors examined the effect of osmium tetroxide (OsO4) on the synovial membrane and cartilage of the rat knee joints by light-, polarization-, and electron microscope. They found that the synovial membrane undergoes severe damage after a 10 min exposure to OsO4. Removing the OsO4 from the joint cavity by perfusion after the 10 min exposure, there was no concomitant damage to the cartilage. Based on experimental results, the authors recommend in human therapy the exposure of the joints to OsO4 for no longer than 10 min and complete removal by exhaustive perfusion.