[Meniscal transplantation with a synovial pedicle--an animal experiment]

The effect of a meniscal transplantation with a synovial pedicle in the avascular portion of the meniscus was investigated in an animal model. An inner (free edge side) half of the middle segment of the medial meniscus, about 6 mm in length, of an adult dog was resected, and a half thickness of the remaining outer (peripheral) meniscus was advanced with a synovial pedicle to fill in the resected portion and sutured with 6-0 interrupted Nylon sutures. As a control, the same procedure without the synovial pedicle was performed for comparison. Twenty-four dogs were treated with synovial pedicle and 13 without. The treated meniscus was excised every four weeks postoperatively up to 32 weeks for gross observation and histological examination. The histological findings at the junction between the advanced meniscus and the remaining meniscus in the group with the synovial pedicle were as follows: 1) At eight to 20 weeks, vascular proliferation and fibroblasts formation were present. 2) At 24 weeks, the vascularity decreased and the junction was filled with collagen fibers. 3) At 32 weeks, the junction was almost completely repaired with chondrocytes. In contrast, in the group without the synovial pedicle, the junction was connected with fibrous tissue, but with no chondrocytes even at 32 weeks. This enhancement of the meniscus repair with the synovial pedicle was considered to be due to reparative ability of the synovial cells, neovascularization through the synovium and viability of the advanced meniscus.(ABSTRACT TRUNCATED AT 250 WORDS)