The present invention concerns amide derivatives of hyaluronic acid (HA) andbiomaterials made of amide derivatives of hyaluronic acid (HA) , particularlythe hexadecylamide of HA, administered by the intraarticular route as apartial/total substitute for synovial fluid to treat joints affected byosteoarthrosis (OA) as well as cases of joint inflammation and/or trauma thatcause damage to the cartilage and/or synovia (associated with pain) . Lastly,we describe and claim their use in the treatment of joints where the entirestructure shows signs of wear due to physiological aging.