Inflammatory involvement in osteoarthritis and lessons to be learnt from animal models.

In a series of 40 rabbits knees experimentally induced osteoarthritis was produced by removal of the lateral or medial meniscus. Ligamentous injury accentuated changes seen in the hyaline cartilage. Within 8 weeks of meniscectomy increased radioisotope uptake was detected by scintigraphy in osteoarthritic knees. At 26 weeks radiological features of osteoarthritis were seen. Scanning electron microscope studies showed surface change on the femoral condyles and tibial plateaux within 4 weeks of meniscectomy and these became progressively more pronounced over the ensuing 18 weeks.