Basic science of articular cartilage repair

Although highly desirable, functional restoration of diseased and damaged human articular cartilage continues to remain one of the most challenging orthopaedic problems. The clinical outcomes of treatments that are intended to promote successful and complete repair of full- and partial-thickness articular cartilage defects essentially remain unpredictable. One of the most exciting theories is that replacement of damaged articular cartilage can be achievable with ex vivo produced cartilage. This is a tissue engineering approach that promises functional restoration of cartilage defects using scaffolds, cells, and bioactive agents. Tissue engineering of articular cartilage represents an exciting direction in the efforts to solve the complex problem of cartilage regeneration. The ex vivo fabrication of cartilage constructs is central in addressing this complex problem in a cogent manner. An accurate delivery system for ex vivo cells has generated great interest. Biodegradable polymer scaffolds of polyglycolic acid material, seeded with articular chondrocytes, support ex vivo genesis of a cartilaginous extracellular matrix, especially when scaffolds are maintained in a system that delivers precise medium composition, supplements, and flow rate.(23,27) This article discusses selected techniques that have been employed to improve the repair potential of articular cartilage, ranging from conventional cell culture to use of complex bioreactors. h treatment regimen that promises consistently good clinical results would constitute an enormous advancement in musculoskeletal surgery.