[Regeneration of the synovia (author's transl)]

Thirteen knee joints of dogs were synovectomized, rearthrotomized after various periods of time and the capsule tissue histologically and submicroscopically evaluated. The synovial cell layer is differentiated into histiocytes and fibroblasts which are genetically related to the local fibrocytes of the remaining tissue or to the mononuclear cell elements of the blood. The cells produce a synovial membrane which rarely differs from the normal membrane. The prerequisite is functional stress. Fourteen weeks after the synovectomy, a normal ultrastructure was formed. The synovia was then capable of bearing strain. The regression of the dystrophic cartilage alterations, the adaptability of the cells to the altered demands and the particular cytoplasmatic structuring of the various cell types are to be understood as an expression of the efficiency of the synovial membrane. Clinical and therapeutic consequences were discussed. In regard to regeneration of the synovia in the diseased joint, a regeneration phase, an efficiency phase and an alteration phase were differentiated.