Method, instruments, and kit for autologous transplantation

#The instant invention concerns the field of chondrocyte transplantation, bone and cartilage grafting, healing, joint repair and the prevention of arthritic pathologies. In particular methods for the preparation of the graft site, instruments for such preparation and for the autologous transplantation of cells to the prepared graft site.

#More than 500,000 arthroplastic procedures and total joint replacements are performed each year in the United States. Approximately the same number of similar procedures are performed in Europe. Included in these numbers are about 90,000 total-knee replacements and around 50,000 procedures to repair defects in the knee per year in Europe. The number of procedures are essentially the same in the U.S. (In: Praemer A., Furner S., Rice, D. P., Musculoskeletal conditions in the United States, American Academy of Orthopaedic Surgeons, Park Ridge, Ill., 1992, 125). A method for regeneration-treatment of cartilage would be most useful, and could be performed at an earlier stage of joint damage, thus reducing the number of patients needing artificial joint replacement surgery. With such preventative methods of treatment, the number of patients developing osteoaithritis would also decrease.

#Techniques used for resurfacing the cartilage structure in joints have mainly attempted to induce the repair of cartilage using subchondral drilling, abrasion and other methods whereby there is excision of diseased cartilage and subchondral bone, leaving vascularized cancellous bone exposed (Insall, J., Clin. Orthop. 1974,101,61; Ficat R. P. et al, Clin Orthop. 1979, 144, 74; Johnson L. L., In: Operative Arthroscopy, McGinty J. B., Ed., Raven Press, New York, 1991, 341).

#The present invention will be better understood by examining the following figures which illustrate certain properties of the instant invention wherein:

#FIG. 1A is a drawing showing a typical articulating end of a bone. Typically, the bone material is covered on the articulating surface with a cartilaginous cap (shown by cross-hatching).

#FIG. 1B shows an example of where a defect or injury to the cartilaginous cap occurs (gap in the cross-hatching), and such a defect can be treated directly, enlarged slightly, or sculpted to accept the grafted material by surgical procedures prior to treatment.

#This invention concerns the use of certain products that inhibit the formation of vascular tissue, for instance such as capillary loops projecting into the cartilage being established, during the process of autologous transplantation of chondrocytes into defects in the cartilage. The formation of vascular tissue from the underlying bone will tend to project into the new cartilage to be formed leading to appearance of cells other than the mesenchymal specialized chondrocytes desired.

#The contaminating cells introduced by the vascularization may give rise to encroachment and over-growth into the cartilage to be formed by the implanted chondrocytes. One of the types of commercial products which can be used in this invention is Surgicel® (Ethicon Ltd., UK) which is absorbable after a period of 7-14 days. The use of this material in the method of the instant invention is contrary to the normal use of a hemostatic device, such as Surgicel® as it is described in the package insert from Ethicon Ltd.

#Surprisingly, we have found that in a situation where you wish to inhibit re-vascularization into cartilage, a hemostatic material material will act like a gel-like artificial coagulate. If red blood cells should be present within the full-thickness defect of articular cartilage that is capped by such a hemostatic barrier, these blood cells will be chemically changed to hematin, and thus rendered unable to induce vascular growth. Thus a hemostatic product used as a re-vascularization inhibitory barrier with or without fibrin adhesives, such as for example the Surgicel®, is effective for the envisioned method as taught by the instant invention. Another part of this invention is the use of a cell-free component, that is used as a patch covering the defective area of the joint into which the cultured chondrocytes/cartilage are being transplanted, using autologous chondrocytes for the transplantation. The method of the invention also contemplates the use of suitable allogenic chondrocytes or xenogenic chondrocytes for the repair of a cartilage defect.