Participants were randomly allocated ( @:@ ) to an intra-articular @-mL injection of the knee with methylprednisolone acetate ( Depo-Medrol ) , @ mg/mL , dissolved in @ mL of lidocaine hydrochloride ( @ mg/mL ) ( corticosteroid group ) or a @-mL isotonic saline injection mixed with @ mL of lidocaine hydrochloride ( @ mg/mL ) ( placebo group ) .