Meniscal regeneration with copolymeric collagen scaffolds

Abstract

We sought to create a regeneration template for the meniscal cartilage of the knee to induce complete men iscal regeneration, and to develop the technique for implanting the prosthetic appliance in vivo. We de signed a resorbable collagen-based scaffold and con ducted 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 me niscus is more clinically relevant to the human menis cus, 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 sup plier. The dogs were deemed clinically and radiograph ically skeletally mature. None of the dogs had a preex isting knee joint abnormality. All dogs underwent an 80% subtotal resection of the medial meniscus bilater ally. 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 scaf fold 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 environ ment of the knee, these studies suggest that effective meniscal regeneration can be supported by an im planted collagen-based scaffold designed to support cellular ingrowth.