[Cultivation and implantation of chondrocytes]

Autologous chondrocyte transplantation is applied in patients with symptomatic articular cartilage defect due to a prior unsuccessful procedure on damaged cartilage, with a purpose to regenerate the cartilage. The procedure starts with an orthopedic surgeon establishing chondral defect in a joint and, during the knee arthroscopy, referring to the laboratory a cartilage biopsy specimen of a rice size from a non-weight-bearing part of the joint (usually the lateral part of the knee trochlea). Qualified biologists and technicians at the laboratory will then separate the cartilage cells from the extracellular matrix, followed by storing parts of healthy cartilage (300-500 mg) into a medium containing antibiotics, antimycotics and ascorbic acid, Individual cartilage cells (chondrocytes) will be isolated by enzymatic digestion. Chondrocytes are finally grown in sterile conditions in the patient's autologous serum during the next 14-21 days. During that time, the culture medium is tested several times in the micro laboratory and the cells' chondrogenic phenotype is determined. Multiplied chondrocytes are then removed from the bottom of the dish, washed several times, counted and prepared in a low volume medium (50-100 microL) suitable for implantation into the injured joint. During the surgery, orthopedic surgeon injects the cell implant under the periosteum or a similar biological membrane covering the defect. Active joint movement starts after 2-3 days, and full weight bearing is achieved in the next several weeks, following the rehabilitation protocol. Full physical condition is achieved within one year. Autologous chondrocyte transplantation is used for treatment of focal articular cartilage defects in the early stages of the disease, thus preventing or delaying progression to osteoarthritis and, consequently, replacement of the joint by an endoprosthesis.