[Regeneration of synovial tissue in rheumatoid arthritis following synovectomy (author's transl)].

A study was carried out on 83 knee joints which had been subjected to synovectomy for rheumatoid arthritis. The morphological changes in the synovial tissue were divided into two types, Type I or hypertrophic and Type II or hypotrophic. Type I (hypertrophic) exhibited oedema, hypervascularization, fibrinous layers, large amounts of villi and granulationlike tissue, lymphocytes and plasma cells. Type II (hypotrophic) contained all the above elements, but to a much lesser degree, and fibrosis was the dominant feature. Regenerated synovial tissue was removed one to three years after the original synovectomy by arthrotomy or biopsy in 26 patients who were symptom-free. The tissue was thinner and hardly any villi were seen. The typical inflammatory elements were seen, but were not as pronounced as in the original tissue, irrespective of type. A heavy fibrosis was most frequently seen, but apart from this the regenerated tissue greatly resembled the original.