Cartilage Repair Using Hydrogels: A Critical Review of in Vivo Experimental Designs

This review analyzes the outcomes and technical aspects of in vivo studies published in the past decade using gels and hydrogels for cartilage repair. Using PubMed search engine, original research publications during the period of 2002/01/01 to 2015/04/30 identified 115 published papers. Of these, 3 studies failed to find a statistically significant improvement of treatment group as compared to control and 18 studies did not clearly identify hyaline-like cartilage formation in the treated groups. The most frequent repaired lesion was the rabbit acute full thickness trochlear defect, using a scaffold combining a gel or hydrogel and other material. One third of the scaffolds were cell-free (35%) and the majority of the studies did not use growth factors (71%). The present review may constitute a useful tool in design of future studies, as limitations of study designs are pointed and results in terms of translation to human application is discussed.