[Structure and function of the "neosynovial membrane." Light and transmission electron microscopy studies of regenerated synovial membranes following surgical synovectomy].

Regenerating synovium from seven patients was examined by light- and transmission electron microscopy. Superficial layers of the "neosynovium" are composed of histocytes, fibroblasts and intermedium cells, developing out of undifferentiated mesenchymal perivascular connective tissue cells. There is no closed cell-layer, as known from mesothelia, endothelia and epithelia. Our results are similar to those of normal synovium and the so-called "pseudo-synovium" of pseudarthroses. So superficial layers of these tissues are comparable specialized connective tissues. According to experimental results in animals, in patients there will develop a "neosynovium" comparable to the original synovium in structure and function. These results confirm synovectomy as a possible operative treatment in patients.