Autologous chondrocyte implantation: a comparison between an open periosteal-covered and an arthroscopic matrix-guided technique.

In this prospective study, the authors compared the Carticel method of autologous chondrocyte implantation with the Hyalograft C technique. The aim of the study was to compare the clinical outcomes of the two methods, to identify any complications and to analyse MRI images of the repair process. Seventeen patients who had received autologous chondrocyte implantation with the Carticel technique and ten treated with Hyalograft C were assessed. A statistically significant improvement was observed in both groups at six months (p < 0.001 for Carticel and p = 0.002 for Hyalograft C) and at twelve months after surgery (p < 0.001 both for Carticel and Hyalograft C), according to HSS (Hospital for Special Surgery) and ICRS (International Cartilage Repair Society) scores. There were no statistically significant differences between the two groups. MRI images obtained one year after surgery revealed the formation of well-integrated tissue similar to the surrounding healthy cartilage in most cases, in both Carticel and Hyalograft C groups. Six patients treated with Carticel technique were also assessed by second-look arthroscopy and histology of biopsies. The newly-formed tissue presented structural features similar to normal cartilage in most cases (84%). Molecular analysis was performed to assess mRNA levels of the various collagen molecules and proliferation and differentiation factors: the results showed that the implanted material undergoes progressive remodelling to regenerate hyaline cartilage. Both Carticel and Hyalograft C implantation techniques seem to lead to comparable short- and medium-term results. Moreover, this study confirmed that MRI is a valid tool in the follow-up evaluation of autologous chondrocyte implantation.