Use of allografts in knee reconstruction: I. Basic science aspects and current status.

Allografts were first used in reconstructive surgery of the knee early in this century. Their widespread use and acceptance paralleled the development of modern tissue banks and our increased understanding of the immune system. Advantages of allogeneic tissue use include less surgical morbidity, shorter surgical time, smaller incisions, and the wider selection of graft sizes and types of tissue. Disadvantages include the risk of disease transmission, a slower biologic remodeling process, and the potential for a subclinical immune response. Allografts can be obtained in several forms, including fresh, fresh-frozen, freeze-dried, and cryopreserved, each with its own advantages and disadvantages. Graft sterility is most commonly ensured by aseptic techniques of harvest and procurement. Other methods, such as irradiation and chemical sterilization, have the potential to damage the collagen structure of the graft and must be used with care. Surgeons who use allografts should make sure that the tissue bank supplying their graft adheres to any applicable guidelines of the Food and Drug Administration and the American Association of Tissue Banks, and uses top-quality testing procedures. In addition, the physician should thoroughly understand the structural and biologic influence of the preservation technique used for that tissue.