A new model of osteoarthritis in rabbits. I. Development of knee joint pathology following lateral meniscectomy and section of the fibular collateral and sesamoid ligaments.

A partial lateral meniscectomy procedure has been developed for the induction of a predictable and reproducible degenerative joint disease in knees of rabbits. The procedure adopted involves section of the fibular collateral and sesamoid ligaments and removal of 4-5 mm of the anterior lateral meniscus. In most experiments the animals are killed and tissues obtained for histologic examination at 6 weeks. Section of the ligaments alone (with or without penetration of the joint space) did not result in significant pathologic change. Significant degeneration was observed in tibial and femoral cartilage when the meniscus as well as the ligaments were cut, but the most extensive lesions were seen when a piece of the anterolateral meniscus was actually removed. These lesions included fibrillation, ulceration and erosion, "clone" and osteophyte formation, loss of chondrocytes, and loss of safraninophilic staining in the articular cartilage. The incidence and distribution of lesions with time following surgery were also investigated. Lesions were observed as early as 1-2 weeks post-surgery and increased in number and severity up to 12 weeks. A global scoring system has been devised to permit statistical comparisons of lesion incidence and severity in different groups of rabbits. This scoring system has enabled us to test drug efficacy in the rabbit lateral meniscectomy model of osteoarthritis.