The invention provides photocrosslinkable, injectable, biodegradable oligo(poly(ethylene glycol) fumarate) (OPF) hydrogels made from the photopolymerization of an OPF macromer with UV light and a photoinitiator. Hydrogels with varying mechanical properties and water content can be made with changes in macromer and crosslinking agent concentration in a precursor solution. The biodegradable OPF hydrogels can be injected as a fluid into a bodily defect of any shape, may incorporate various therapeutic agents, e.g., cells and/or growth factors, and may be implanted via minimally invasive arthroscopic techniques.