Cartilage tissue engineering: Current limitations and solutions

Articular cartilage repair remains one of the most intensely studied orthop aedic topics. To date the field of tissue engineering has ushered in new me thodologies for the treatment of cartilage defects. The authors' 10-year ex perience using principles of tissue engineering applied to resurfacing of c artilage defects is reported. Which cell type to use, chondrocytes versus c hondroprogenitor cells, and their inherent advantages and disadvantages are discussed. Chondrocytes initially were used as the preferred cell type but were shown to have long term disadvantages in models used by the authors. Mesenchymal stem cells can be used effectively to overcome the Limitations experienced with the use of differentiated chondrocytes. The use of mesench ymal stem cells as platforms for retroviral transduction of genes useful in cartilage repair introduces the concept of gene modified tissue engineerin g, The fundamental conditions for promoting and conducting a viable cartila ge repair tissue, regardless of which cell type is used, also were studied. Placement of a synthetic porous biodegradable polymer scaffold was found t o be a requirement for achieving an organized repair capable of functionall y resurfacing a cartilage defect. A new modular device for intraarticular f ixation of various graft composites has been developed. This new cartilage repair device is composed of bioabsorbable polymers and is capable of being delivered by the arthroscope.