[Synovial membrane and cartilage changes in an arthrosis model. Instability and impact stress model]

Surgical instability and repetitive impulsive loading was used to generate degenerative changes in knee joints of rabbits. Light- and electronmicroscopy was carried out at synovial membrane and cartilage samples. The instabilised joints had early synovial inflammation, preceding overall cartilage changes. Synoviocytes were activated and showed more and dilatated cytoplasmatic organells. Invaded round cells--potentially cartilage degenerative--were seen. In the loading model no initial synovial inflammation could be seen. Focal cartilage changes were located at the weight bearing zone. Two different inductive pathways may be involved in cartilage breakdown comparing the two arthrosis models. Mechanical factors seemed to trigger cartilage changes in the loading model, an inflammatory synovial pathway is likely to initiate cartilage breakdown in the instability model.

The synovial membrane has the key-position for the cartilage degeneration in posttraumatic joint affections. The therapeutic use of antiphlogistic substances is indicated to supreme inflammatory mediators from the synovial membrane. This therapeutic concept seemed not to be useful in primary mechanical induced osteoarthrosis.