Comparative effectiveness of osteochondral restoration, cell-based regeneration and cell-free implants for knee chondral defects

Abstract

OBJECTIVES: Chondral defects of the knee can impair function, reduce quality of life and accelerate progression to osteoarthritis. Treatment aims to delay further cartilage damage and reduce the risk of early-onset osteoarthritis and knee replacement. This systematic review evaluated the effectiveness and safety of chondral defect repair procedures on the knee.

DESIGN: Systematic review.

DATA SOURCES: PubMed and Cochrane Library.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Interventions were matrix-induced autologous chondrocyte implantation (MACI), osteochondral autologous transplantation (OATS) and cell-free implants. Comparators included microfracture (MF). Eligible study designs were randomised controlled trials (RCTs) and comparative non-randomised studies of interventions (NRSIs). Eligible outcomes included patient-reported outcomes (PROs), clinical response, treatment failure, reoperation and harms. Risk-of-bias assessments (RoB) on all included studies were assessed using the Cochrane Risk of Bias (RoB 2) for the RCTs and Risk Of Bias In Nonrandomized Studies of Interventions tool for the NRSIs.

RESULTS: 13 studies reported effectiveness and 8 studies reported harms. MACI was more effective than MF, measured by PROs and response to treatment (moderate certainty of evidence (COE) from RCTs, very low to low COE from NRSIs). Evidence comparing OATS with MF suggested no difference in effectiveness, as measured by PROs (low COE from RCTs and very low COE from NRSIs). MACI and OATS had similar harms to MF (COE low and very low). Evidence for cell-free implants suggested greater effectiveness (moderate COE) and fewer harms (low COE) compared with MF. No studies compared these procedures to sham surgery or conservative management.

CONCLUSION: MACI and OATS showed greater or comparable effectiveness compared with MF. Harms were comparable between procedures, though reporting was sparse. Rigorous study design, standardised effectiveness outcomes and consistent reporting of harms would strengthen the evidence base. These findings can inform clinical decision-making and identify future research needs.