Autologous Chondrocyte Transplantation for Cartilage Defects in the Knee Joint

A Cochrane review 3 (abstract , review [Abstract]) included 6 studies with a total of 431 subjects. Three trials compared autologous chondrocyte implantation (ACI) versus mosaicplasty. One reported statistically significant results for ACI at one year in the numbers of people with 'good' or 'excellent' functional results. Conversely, another trial found significant improvement for the mosaicplasty group when assessed using one functional scoring system at two years, but no statistically significant differences based on two other scoring systems. A third trial found no difference between ACI and mosaicplasty, 10 months on average after the surgery. There was no statistically significant difference in functional outcomes at two years in single trials comparing ACI with microfracture or characterised chondrocyte implantation versus microfracture. The results of the sixth trial comparing matrix-guided ACI versus microfracture were undermined by the severe loss to follow-up.

A technology assessment report 1 on autologous chondrocyte transplantation (ACT) was abstracted in the Health Technology Assessment Database. According to cohort studies, of patients who have knee injuries with hyaline cartilage defects 71% to 77% report a good or excellent outcome with ACT at two years. With comparator treatments the range is between 10% and 95%. The wide range for comparator treatments may reflect patient heterogeneity rather than treatment effect. In the absence of controlled trials autologous chondrocyte transplantation should be regarded as an experimental therapy. Over 10 years the expected cost of treating patients with ACT was estimated at 10 400 GBP compared with 3 000 GBP for other options for treating cartilage defects. An estimate of the expected cost per QALY gained with ACT was 9 000 GBP (best case 1 700 GBP, worst case 13 700 GBP).

Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment), by inconsistency (heterogeneity in interventions and outcomes and variability in results across studies), and by imprecise results (few patients and wide confidence intervals).

References

• Jobanputra P, Parry D, Meads C, Burls A. Autologous chondrocyte transplantation for cartilage defects in the knee joint. Birmingham: West Midlands Health Technology Assessment Collaboration (WMHTAC), Department of Public Health and Epidemiology, University of Birmingham 2001:88. [DARE]
• Vasiliadis HS, Wasiak J. Autologous chondrocyte implantation for full thickness articular cartilage defects of the knee. Cochrane Database Syst Rev 2010;(10):CD003323. [PubMed].