Adjuvant therapies for the enhancement of microfracture technique in cartilage repair

The classic technique of microfracture does not promote hyaline cartilage restoration. Subchondral bone perforations lead to the formation of a clot containing pluripotent progenitor cells and finally the cartilage defect is filled by fibrocartilage tissue. Researchers have focused on enhancing the quality of the newly formed tissue in cartilage defects after microfracture arthroscopic surgery. Adjuvant treatments are categorized in four main groups: scaffolds, pharmaceutical agents, growth factors and combinations of the aforementioned. Several experimental studies utilize pharmaceutical or biological agents in combination with microfracture, to improve the quality of the regenerated cartilage. The mechanism of action of the agents used is either to exert a chondroprotective effect on the newly formed fibrocartilage tissue, or to induce the recruitment of mesenchymal stem cells towards chondrogenesis instead of osteogenesis during microfracture repair. Additionally, scaffolds have been used for both release of the biological agents and mechanical support of the newly formed blood clot. This review highlights current data regarding the combination of microfracture technique with adjuvant treatments in order to ameliorate the final outcome.