In order to observe the early histopathological changes in the experimental model of degenerative arthritis, 50 immature rabbits weighing from 400 to 500gm and 50 mature rabbits weighing from 1000 to 2000 gm were used to make unstable knees.
In the control group, a sham operation (arthrotomy only) was performed in each 10 of immature and mature rabbits.
In the group I, each 20 of immature and mature rabbits had section of medial collateral ligament and anterior cruciate ligament. In the group II, each 20 of immature and mature rabbits had section of medial collateral ligament and anterior cruciate ligament with excision of medial meniscus.
The immature and mature rabbits were killed after 2, 4, 8,12, and 16 weeks. Histopathological changes were examined in the articular cartilage of the tibia, femur and patella.
The results obtained are as follows ;
1. In the group I (section of medial collateral and anterior cruciate ligament) and the group II (section of medial collateral and anterior cruciate ligament with excision of medial meniscus) of immature and mature rabbits, histopathological changes in the articular cartilage of the knee joint were more distinct in the medial tibial condyle than in the femur and lateral tibial condyle, and minimal in the patella.
2. In the group I and II of immature and mature rabbits, histopathological changes of degenerative arthritis such as disarray of arrangement of chondrocyte, cloning, surface irregularity, erosion, fibrillation, splitting and capillary penetration of the calcified cartilage were observed, while no osteophyte formation was observed.
3. In the group II, degenerative changes in the articular cartilage of both immature and mature rabbits were observed earlier and more remarkable than those in the group I.
4. In the immature rabbits, degenerative changes in the articular caritilage were observed earlier and more remarkable than those in the mature rabbits.
5. In the immature rabbits, histopathological changes in the experimental model of degenerative arthritis resulted from knee instability by section of or combined wAh excision of meniscus were MmMar to those in the mature rabbits.
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