Debrided articular cartilage: A novel source of chondrocytes for articular cartilage repair

Autologous chondrocyte implantation (ACI) is the most promising treatment for large full thickness knee joint articular cartilage (AC) defects where cells from healthy non-weight bearing area AC are grown in vitro and implanted into defects. In a routine surgical procedure for knee joint defects, AC around the edge of defects is usually debrided and discarded. The purpose of this study is to examine if this 'debrided' AC (DAC) can proliferate, synthesize a cartilage specific matrix and can thus be used for ACI. Biopsies were retrieved from 11 patients (DAC, aged 27-61) and from 2 autopsies (Normal AC, NAC, aged 21 & 25). Chondrocytes were isolated, seeded at low density in Type I collagen gels and cultured for 4 weeks. Cells from DAC proliferated more than cells from NAC. Rate of proteoglycan synthesis was similar but rate of collagen synthesis from DAC was lower than NAC. Newly synthesized matrices consisted predominantly of type II collagen as shown by immunolabeling and SDS-PAGE followed by fluorography. Chondrocytes from 'debrided human AC' cultured at low density in Type I collagen gels can be used for ACI procedure as they provide sufficient viable cell numbers for ACI and also synthesize a cartilage-like matrix.