The purpose of this study was to investigate the reparative and regenerative capacity of SurgiMend® (TEI Biosciences, Inc.) an FDA-approved collagen matrix, when placed into a meniscal defect in swine.
The medial meniscus was exposed in twelve swine. Three, 4 mm full-thickness cylindrical defects were made in the meniscus. SurgiMend implants were fit into the defects and secured with suture. One control site was untreated without implant. The other control site was treated with a cylinder of meniscus removed when making the defects and sutured. Three animals were euthanized at 3 weeks, three at 8-10 weeks, and three at 6 months. Tissues were harvested and studied grossly, immunohistochemically, and histologically.
At three weeks the collagen implants were apparent in the defect and populated with cells. By 8-10 weeks, the implants were integrated with the meniscus with evidence of healing. The implants were revascularized and repopulated by cells that resembled fibrochondrocytes typical of meniscal tissue. Healing of the scaffold to native meniscus was always observed at peripheral contact site and frequently at the interface with the white zone. No evidence of inflammatory cells was present. The results at 6 months mirrored those seen at the 3 month time point with regeneration of the defect in which the implant was placed.
The bovine dermal collagen scaffolds integrated into the defects. Cell migration into the scaffold material occurs by three weeks. The scaffolds were undergoing remodeling by eight weeks, being populated by fibrochondrocytes, and integrating into the defects. These results show that the bovine dermal matrix is capable of permitting repair and regeneration of meniscal lesions in swine. This model was effective for evaluating the biocompatibility and regenerative capacity of the material. Future testing should focus on replacing the inner rim of the meniscus to simulate repair in humans.