AUTOLOGOUS CHONDROCYTE IMPLANTATION (ACI-C) AND MATRIX-CARRIED AUTOLOGOUS CHONDROCYTE IMPLANTATION (MACI) IN THE MANAGEMENT OF CHONDRAL AND OSTEOCHONDRAL DEFECTS OF THE KNEE: NINE-YEAR FOLLOW-UP OF A SINGLE CENTRE PROSPECTIVE STUDY

Abstract

Introduction: Initial results for the management of osteochondral defects with both ACI-C and MACI have been encouraging, showing significant clinical improvements. This study set out to report the functional, clinical and histological outcomes in our institution following nine years experience of cartilage-cell transplants.

Aim: Reporting results of nine-year experience of clinical and arthroscopic assessment in the use of ACI and five year experience of MACI in the management of symptomatic, full-thickness chondral and osteochondral defects in the knee.

Method: Following preoperative functional assessments, arthroscopic harvesting of chondrocytes for culture was performed and patients underwent ACI-C or MACI. In ACI-C a covered technique is employed using a porcine-derived type I/III collagen membrane sutured in place; MACI requires cultured autologous chondrocytes to be seeded in a bi-layered type I/III collagen membrane which is glued into position. An arthroscopy was performed between 12 and 24 months post-procedure to assess graft coverage and biopsies taken to determine extent of hyaline, mixed and fibro-cartilage proliferation.

Results: 354 patients underwent either ACI-C (103) or MACI (251) with an average age of 31.3 (15–54). Cincinnati knee rating scores recorded prior to assessment arthroscopy for ACI-C: 58.6 (12 – 92) and MACI: 48.4 (11 – 90) showed improvement at follow up with means of 84.0 for ACI-C, with 78% of patients scoring good or excellent at nine years, and a mean of 82.3% in the MACI group at five years, with 87% of patients recording good or excellent scores; statistically significant improvement was also noted in Bentley Functional score. Biopsies of the transplants taken between 12 and 24 months revealed proliferation of hyaline and mixed cartilage (hyaline and fibro-cartilage) in 47% patients; the later the biopsy was taken post-implantation, it was more likely to reveal hyaline tissue.

Conclusion: Results to date suggest significant clinical and arthroscopic improvement following ACI-C and MACI, with evidence of proliferation of hyaline cartilage at the transplant site and evidence to suggest dynamic improvement in hyaline-nature of cartilage. Limited differences are noted between the outcomes of the two techniques.