Abstract: An injectable viscoelastic hydrogel formulation comprising photocrosslinked hyaluronic acid in order to relieve pain caused by osteoarthritis (OA), to support synovial fluid which has decreased activity, and to treat osteochondral lesions is provided. In the production of hyaluronic acid (HA) hydrogels, the crosslinking process is carried out via biocompatible camphorquinone instead of synthetic crosslinkers having toxic effects. Therefore, long process times in the purification process of synthetic crosslinkers are significantly reduced with the present invention.