Cartilage repair mixture containing allograft chondrocytes

Abstract

The invention is directed toward a sterile cartilage defect implant material comprising milled lyophilized allograft cartilage pieces ranging from 0.01 mm to 1.0 mm in size in a bioabsorbable carrier taken from a group consisting of sodium hyaluronate, hyaluronic acid and its derivatives, gelatin, collagen, chitosan, alginate, buffered PBS, Dextran or mixed polymers with allograft chondrocytes added in an amount ranging from 2.5×105 to 2.5×107.

Description

RELATED APPLICATIONS [0001] There is no related application. FIELD OF INVENTION [0002] The present invention is generally directed toward an implant and is more specifically directed toward a paste or gel implant material including allograft for a cartilage defect BACKGROUND OF THE INVENTION [0003] Articular cartilage injury and degeneration present medical problems to the general population which are addressed by orthopedic surgeons. Every year in the United States, over 500,000 athroplastic or joint repair procedures are performed. These include approximately 125,000 total hip and 150,000 total knee arthroplastics and over 41,000 open arthroscopic procedures to repair cartilaginous defects of the knee. [0004] In the knee joint, the articular cartilage tissue forms a lining which faces the joint cavity on one side and is linked to the subchondral bone plate by a narrow layer of calcified cartilage tissue on the other. Articular cartilage (hyaline cartilage) consists primarily of ex...

AI Technical Summary

Benefits of technology

[0018] A cartilage implant material in paste or gel form for repairing articular cartilage defects is composed of milled allograft cartilage pieces and allograft chondrocytes in a bioabsorbable carrier. Allograft chondrocytes occurring in hyaline cartilage from a neonate (age 3 months) to young adult 20 years of age are added to the implant material and the cartilage pieces are taken from the same donor. Additives may be applied to the mixture in order to increase chondrocyte migration and proliferation The implant material can support the addition of a variety of chondrogenic stimulating factors including, but not limited to growth factors (FGF-2, FGF-5, IGF-1, TGF-β, BMP-2, BMP-7, PDGF, VEGF), human allogenic or autologous bone marrow cells, stem cells, demineralized bone matrix, iusulin, insulin-like growth factor-1, transforming growth factor-B, interleukin-1 receptor antagonist, hepatocyte growth factor, platelet-derived growth factor, Indian hedgehog and parathyroid hormone-related peptide or bioactive glue.

[0020] It is an object of the invention to provide an allograft implant material for joints which provides pain relief, restores normal function and will postpone or alleviate the need for prosthetic replacement.

[0021] It is also an object of the invention to provide a cartilage repair implant material which is easily placed in a defect area by the surgeon using an arthroscopic, minimally invasive technique.

[0023] It is yet another object of the invention to provide an allograft implant material which facilitates growth of hyaline cartilage through the use of allograft chondrocytes.

Problems solved by technology

If the lining becomes worn or damaged resulting in lesions, joint movement may be painful or severely restricted.

Whereas damaged bone typically can regenerate successfully, hyaline cartilage regeneration is quite limited because of it's limited regenerative and reparative abilities.

Articular cartilage lesions generally do not heal, or heal only partially under certain biological conditions due to the lack of nerves, blood vessels and a lymphatic system.

The limited reparative capabilities of hyaline cartilage usually results in the generation of repair tissue that lacks the structure and biomechanical properties of normal cartilage.

Generally, the healing of the defect results in a fibrocartilaginous repair tissue that lacks the structure and biomedical properties of hyaline cartilage and degrades over the course of time.

These lesions are difficult to treat because of the distinctive structure and function of hyaline cartilage.

Osteoarthritis is the leading cause of disability and impairment in middle-aged and older individuals, entailing significant economic, social and psychological costs.

None of these therapies has resulted in the successful regeneration of hyaline-like tissue that withstands normal joint loading and activity over prolonged periods.

These techniques provide temporary pain relief, but have little or no potential for further healing.

Penetration into the subchondral bone induces bleeding and fibrin clot formation which promotes initial repair, however, the tissue formed is fibrous in nature and not durable.

There have also been problems with adhesion and stability of the grafts, which result in their displacement or loss from the repair site.

As with the perichondrial graft, patient / donor age may compromise the success of this procedure as chondrocyte population decreases with increasing age.

Disadvantages to this procedure include the need for two separate surgical procedures, potential damage to surrounding cartilage when the periosteal patch is sutured in place, the requirement of demanding microsurgical techniques, and the expensive cost of the procedure which is currently not covered by insurance.

Reports of results of osteochondral plug autografts in a small number of patients indicate that they decrease pain and improve joint function, however, long-term results have not been reported.

Factors that can compromise the results include donor site morbidity, effects of joint incongruity on the opposing surface of the donor site, damage to the chondrocytes at the articular margins of the donor and recipient sites during preparation and implantation, and collapse or settling of the graft over time.

The limited availability of sites for harvest of osteochondral autografts restricts the use of this approach to treatment of relatively small articular defects and the healing of the chondral portion of the autograft to the adjacent articular cartilage remains a concern.

Drawbacks associated with this methodology in the clinical situation include the scarcity of fresh donor material and problems connected with the handling and storage of frozen tissue.

Fresh allografts carry the risk of immune response or disease transmission.

Frozen allografts lack cell viability and have shown a decreased amount of proteoglycan content which contribute to deterioration of the tissue.

The use of implants for cartilage defects is much more limited.

Concerns associated with this method are harvest site morbidity and availability, similar to the mosaicplasty method.

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