I just went through an Angiolplasty procedure because, though I have competed for the last 6 years in 5k's - in the 70+ groups, I could no longer do it because the artery in my left leg was clogged right behind my replaced knee. I had the procedure last Friday (5 days ago) and am thrilled with the results!
Maybe you have a clogged artery or vein in your thigh. Have you checked for that? My Primary Care physician recommended that I I see a vascular surgeon who performed the procedure.
Good Luck!