Our data shows, for the first time, that administration of intra-articular injections of FGF18 into the TMJ of mice with induced cartilage degeneration led to an increase in cartilage thickness, proteoglycan distribution, proliferation of chondroprogenitors and decreased markers for osteoarthritis, suggesting that FGF18 promotes repair of the TMJ fibrocartilage. This evidence concerns the gene FGF18 and osteoarthritis.