Articular cartilage injury is one of the more common diseases in orthopedics. In the field of orthopaedic surgery, arthritis caused by traumatic and degenerative cartilage tissue injury due to disease and trauma is a challenge in the medical field worldwide. Since cartilage tissue has no blood supply and is nourished by the surrounding synovial fluid, it is difficult to regenerate after injury. Traditional treatments for cartilage injury include joint grinding and shaping, drilling, microfracture and arthroscopic lavage, all of which fail to repair the damaged cartilage and subchondral bone to their original normal tissue structure. Autologous tissue transplantation is more effective but has a limited supply of material; allogeneic material is relatively more available but may cause immune rejection and has the risk of spreading disease. In this context, the development of injured tissue substitutes using tissue engineering is a promising therapeutic approach. The principle of tissue engineering for cartilage repair is to clinically extract the patient’s autologous cartilage cells and then adsorb the cells into a collagen cartilage carrier that is biocompatible and can be gradually absorbed by the body, which provides a three-dimensional space for the cells to survive, facilitates the cells to obtain sufficient nutrients, conduct gas exchange, excrete waste, and allows the cells to grow and expand according to a pre-designed three-dimensional morphological scaffold . The obtained grafts are implanted into the diseased part of the tissue in the organism, and the implanted cells continue to proliferate and secrete matrix during the gradual absorption of the biological scaffold, forming new corresponding cartilage tissues with the special morphology and function of the tissue cells in situ, and the patient obtains the repair and functional reconstruction of the cartilage defect by customizing and transplanting autologous cartilage grafts to achieve complete cure and lasting recovery. Autologous chondrocyte transplantation is one of the more widely used tissue engineering techniques for the treatment of articular cartilage injuries. The MACI technique is one of the more mature autologous chondrocyte transplantation techniques in clinical practice. MACI (Matrix-induced autologous chondrocyte implantation) is a technique in which clinically collected chondrocytes are pre-grafted onto a biofilm and the resulting graft is transplanted into the defect by means of fibrous adhesive fixation. The advantages of MACI technology over traditional chondrocyte transplantation technology are: 1. The MACI technique has the following advantages over the traditional chondrocyte grafting technique 2. Using collagen membrane as the chondrocyte carrier, no need to cut the periosteum, avoiding various complications caused by periosteal transplantation to the joint surface. 3.The graft site is closed with biocompatible fiber glue instead of sutures, so sutures are not needed. 4.Small surgical incision, short operation time and fast postoperative recovery. In the current clinical application in this field, the Cartilage Regeneration System (CaReS) jointly developed by the UK and Germany has won the German Science and Technology Major Achievement Award and is of international leading level. The technology was introduced into China in 2007, and 27 clinical applications were completed in Hong Kong in the same year. In 2009, the technology was licensed by the State Food and Drug Administration for clinical trials, and has been carried out in many tertiary hospitals in China, and its clinical efficacy has been confirmed by a large number of clinical cases. According to the “Measures for the Administration of Clinical Application of Medical Technologies” and “Notice of the First Catalogue of Class III Medical Technologies Allowed for Clinical Application” published by the Ministry of Health on June 11, 2009 and the “Technical Management Specification for Tissue Engineering Tissue Transplantation Therapy” issued on November 13, 2009, “Cartilage Regeneration System” can be carried out in tertiary hospitals with the conditions for tissue engineering tissue transplantation therapy. Clinical application. The introduction of this cartilage regeneration technology in our hospital will enable more patients with cartilage injury to receive satisfactory treatment. CaReS autologous cartilage grafting is used to treat cartilage defects in the knee with a defect area of 2.5-10 cm2 and an Outerbridge classification of III to IV. The CaReS treatment protocol is divided into four steps: Step 1: Preoperative evaluation; Step 2: Minimally invasive arthroscopic surgery to remove the sample; Step 3: Implantation of the cartilage regeneration system; Step 4: Postoperative rehabilitation. Step 1: Preoperative evaluation Articular cartilage damage may be found during arthroscopy of many knees. Many patients with other injurious knee conditions (such as cruciate ligament or meniscal injuries) have concomitant articular cartilage damage. Prior to arthroscopic management, it is best to have your doctor also perform an articular cartilage evaluation. Articular cartilage damage can be diagnosed by physical examination, x-ray and MRI. Once you have been diagnosed with a knee cartilage injury, if you agree to be treated with the CaReS technique, your doctor will give you a detailed description of your treatment plan and schedule an appointment for your surgery. If you have any other medical conditions that may adversely affect your surgery, especially heart disease, diabetes, high blood pressure, liver disease, kidney disease or dental disease, please inform your doctor so that they can be effectively managed or treated prior to surgery, which will help you heal and reduce the risk of surgery. Step 2: Minimally invasive arthroscopy: Through a minimally invasive arthroscopic procedure, a 75mg sample of healthy cartilage tissue (the size of a grain of rice) will be scraped from the non-weight-bearing area of your damaged knee cartilage and approximately 120ml of your own blood will be taken prior to anesthesia for the preparation of your cartilage graft. Because the sample size is small and the cartilage tissue is taken from a non-weight-bearing area, there is no impact on your health. Step 3: Implantation of the Cartilage Regeneration System It takes only 12-18 days after the minimally invasive arthroscopic procedure to obtain a graft containing your own cartilage cells, which will be surgically fixed to your cartilage defect using fibrin glue. Step 4: Post-operative rehabilitation Because CaReS is a simple procedure, the incision has a low chance of infection and recovery is quick. In order for the cartilage graft implanted into your body to grow into the same hardness and shape as your healthy cartilage tissue, and thus achieve better repair results, your doctor will develop a rehabilitation plan during and after your hospitalization according to the location and size of your cartilage defect, which will be especially important for you.