Tissue Engineering for Cartilage Repair

Abstract

Articular cartilage lacks intrinsic regenerative capacity, and current surgical interventions produce fibrocartilage that degrades under joint loading within years, leaving tissue engineering as the most promising route to durable hyaline cartilage restoration. We evaluated 218 cartilage tissue engineering programmes conducted across orthopaedic research centres in France, Austria, and Estonia between 2014 and 2024, spanning five scaffold categories: hydrogel-based constructs, decellularised matrix scaffolds, electrospun fibre mats, bioprinted osteochondral units, and scaffold-free cell-aggregate approaches. A Cartilage Tissue Engineering Translational Index (CTETI) was constructed from five sub-scores -- hyaline cartilage phenotype fidelity, mechanical competence under loading, construct-host integration quality, in vivo durability beyond 12 months, and manufacturing reproducibility -- with weights from regression against progression to next-phase clinical trials. CTETI correlated with translational advancement at r = +0.83 and discriminated advancing from stalled programmes with an AUC of 0.876. Hydrogel-based constructs scored highest (mean CTETI 0.812), while scaffold-free approaches trailed at 0.594. Only 32.6 percent of programmes exceeded the 0.75 CTETI threshold. Hyaline phenotype fidelity carried the largest regression weight (beta = +0.278), followed by mechanical competence (beta = +0.228).