Meniscal repair enhanced by an interpositional free synovial autograft: an experimental study in rabbits

This report describes the methods and effectiveness of interpositional free synovial autografts (IPFSAs) in promoting the healing of lesions in the avascular portion of the knee joint meniscus in rabbits. Thirty-four specimens were divided into two groups: 17 in the study group and 17 in the control group. The medial meniscus of the left knee joint was excised in each rabbit, and an artificial longitudinal tear was created in the avascular zone of the meniscus. In the study group, an IPFSA was sewn into the tear with a single horizontal suture. In the control group, the tear was repaired without synovium in the same manner. The menisci were then implanted into the right knee joint in the respective animals. At intervals the animals were killed, and the menisci were examined grossly and microscopically. Three menisci were eliminated because they had become attached to the synovial wall. In the study group, the lesion completely healed by 4 weeks, except for one. The menisci in the control group never completely healed, particularly at the deeper levels of the lesion. At 8-16 weeks, autolysis of the specimens made microscopic examination difficult and unreliable in both groups. Based on these results, it has been concluded that an IPFSA can promote the healing process in the avascular zone of a torn meniscus in rabbits and that systemic vascularity to the synovium or the meniscus is not essential for healing to occur.