Objectives: Chondral defects of the knee cartilage are prevalent. Autologous chondrocyte implantation (ACI) and mosaicplasty are increasingly used to treat symptomatic knee defects. This study assessed the costs and health status outcomes after ACI and mosaicplasty.

Methods: Patients were eligible to participate in this cross-sectional study if they received ACI or mosaicplasty at the Royal National Orthopaedic Hospital between 1997 and 2001 or were on a waiting list for ACI. Secondary-care resource use was collected to 2 years postoperatively using a resource collection proforma. Participants responded to postal questions about sociodemographic characteristics and knee-related (Modified Cincinnati Knee Rating System) and general health status (EQ-5D).

Results: Fifty-three ACI, twenty mosaicplasty, and twenty-two patients waiting for ACI participated. The average cost per patient was higher for ACI (£10,600: 95 percent confidence interval [CI], £10,036–£11,214) than mosaicplasty (£7,948: 95 percent CI, £6,957–£9,243). Postoperatively, ACI and mosaicplasty patients (combined) experienced better health status than those waiting for ACI. ACI patients tended to have better health status outcomes than mosaicplasty patients (not statistically significant). Estimated average EQ-5D social tariff improvements for quality-adjusted life year (QALY) calculations were 0.23 (ACI) and 0.06 (mosaicplasty). Average costs per QALY were £23,043 (ACI) and £66,233 (mosaicplasty). The incremental cost effectiveness ratio (ICER) for providing ACI over mosaicplasty was £16,349.

Conclusions: Average costs were higher for ACI than mosaicplasty. However, both the estimated cost per QALY and ICER for providing ACI over mosaicplasty fell beneath an implicit English funding threshold of £30,000 per QALY. Prospective studies should include measures of utility to confirm the estimated cost utility ratios of ACI and mosaicplasty.