Hi My Husband Had A Stent Put In His Left

Hi my husband had a stent put in his left leg 12-2-15 went for his follow up Dr.said it looked good..but now his knee an behind the knee is hurting and right also noticed sum swelling in his left ankle the stent that was put in was just above the knee..my question is could the stent close or could he have a blood clot..he can't hardly walk it's like his knee is stiff an locks up an hurts to walk