Advances in injectable hydrogels for cartilage repair of osteochondral lesions of the talus

Osteochondral lesions of the talus (OLT) have been a prevalent clinical condition which poses significant challenges in surgical treatment. Extensive surgical incisions, high risk of infection, limited biocompatibility, insufficient early-stage support for the injured cartilage after surgery, long recovery time, and inferior mechanical properties of the fibrocartilage, all these challenges increase the probability of injury recurrence and the risk of secondary infection. This review was performed in accordance with PRISMA-Scr guidelines. A systematic search in PubMed using the string: (osteochondral OR osteochondrosis) AND injectable hydrogel retrieved 100 records. Studies on hydrogel microspheres, non-weight-bearing cartilage, and those published before 2019 were excluded. This review focuses on summarizing the advances of injectable hydrogels to address the challenges and problems faced in OLT. A total of 34 eligible studies focusing on injectable hydrogels for osteochondral lesion repair were included in analysis. It has been well demonstrated that the mechanical stability and biocompatibility of hydrogels in vivo can be markedly improved by modifying their chemical and physical properties. In addition, the injectability and minimally invasive implantation of hydrogels can reduce incision size, decrease the risk of infection, and accelerate patients’ recovery. In recent years, a hydrogel, a new type of biomaterial, has shown potential in the clinical treatment of OLT thanks to its good biocompatibility, adjustable mechanical properties, and ability to carry cells and bioactive factors. The injectability of hydrogels confers a significant advantage in minimally invasive implantation, which provides a new strategy for the treatment of OLT. • Osteochondral lesions of the talus (OLT) is a challenging clinical condition awaiting new therapeutic approaches. • Hydrogel has good biocompatibility, adjustable mechanical properties, and ability to carry cells and bioactive factors. • Hydrogel applications can reduce surgical wound infections, mitigate post-operative support issues, and speed up cartilage repair. • Addressing the translational gaps is critical for successful implementation of hydrogel-based therapies of OLT.