[Regenerative processes of the internal structures of the knee joint following meniscectomy. Experimental study of the knee joint of the rabbit].

In an experimental study of thirty rabbits, processes of repairing of the inner structures in the knee joint after meniscectomy were examined: Three operational methods were used: The total, partial and sub-partial menisectomy. Macroscopic, microscopic and electron microscopic examinations of the inner structure of the knee joint were made after intervals of one, three, six, nine and twelve weeks after meniscectomy. Processes of adaptation in the articulating parts of the joints were detected after total and sub-total menisectomy. These were in the form of marginally located chrondo-osteophytic deposits. Very little change or no change at all could be found in the tibia and the femur, where a sub-total meniscectomy had been performed. A regenerative development took place in the capsular part of the resection line of the meniscus and/or the anterior part of the meniscus. The regeneration consisted of connective tissue rich in collagen fibres. No cartilage tissue could be found. There was no regenerative development in evidence after performing a sub-total menisectomy. Closure of the lesion/defect to the original half moon shape was not observed. The inner edge of the meniscus base showed itself to be unchanged. Intermediate cartilage structures remaining in the joint after the performance of partial and sub-total meniscectomy showed evidence of changes in connective tissue composition. Microscopy showed changes in its connective tissue through increased layering of collagen tissue in the cartilaginous tissue matrix. Adaptation processes in the tibia and the femur after total and partial meniscectomy indicate a low functional regenerative efficiency.