MENISCAL REGENERATION WITH COPOLYMERIC COLLAGEN SCAFFOLDS - INVITRO AND INVIVO STUDIES EVALUATED CLINICALLY, HISTOLOGICALLY, AND BIOCHEMICALLY

We sought to create a regeneration template for the meniscal cartilage of the knee to induce complete meniscal regeneration, and to develop the technique for implanting the prosthetic appliance in vivo. We designed a resorbable collagen-based scaffold and conducted in vitro and in vivo studies. In vivo, the scaffold was implanted in the knees of immature swine and mature canines and evaluated clinically, histologically, and biochemically. Because the canine stifle joint meniscus is more clinically relevant to the human meniscus, this paper emphasizes those results. We studied 24 mixed breed dogs (14 males and 10 females) with an average weight of 25.5 kg (range, 20 to 35) that were obtained from a USDA-licensed supplier. The dogs were deemed clinically and radiographically skeletally mature. None of the dogs had a preexisting knee joint abnormality. All dogs underwent an 80% subtotal resection of the medial meniscus bilaterally. A collagen template was implanted in one stifle (N = 24). The contralateral side served as a control: 12 dogs had a total resection alone and the other 12 dogs had an immediate replantation of the autologous meniscus. Results were tabulated at 3, 6, 9, and 12 months. At final evaluation, before the animals were euthanized, the results were submitted for statistical analysis as well as histologic and biochemical analyses. The results demonstrated that a copolymeric collagen-based scaffold can be constructed that is compatible with meniscal fibrochondrocyte growth in vitro and in vivo, that does not inhibit meniscal regeneration in an immature pig, and that may induce regeneration of the meniscus in the mature dog. Although additional studies are necessary to perfect the scaffold and to evaluate the implant in the environment of the knee, these studies suggest that effective meniscal regeneration can be supported by an implanted collagen-based scaffold designed to support cellular ingrowth.