What Causes Worsening Left Lateral Leg Pain, Heaviness, And Tightness, With Stroke-like Ambulation After A Successful TKR Two Years Ago?

I had a tkr (left knee), without incident 2 years ago. I have had no problems to date with exercise and movement. At the end of last week, my left lateral leg pain became worse, and my leg felt heavy and I appeared to have stroke-like ambulation, in that, I appeared to be carrying my leg. Some pain upon adduction. No redness. Leg and foot feel tight.