about 5 months post total knee replacement I was going up and down stairs with little trouble. I then went down two steps at a time by mistake and the pain was excruciating. The next day at the surgeon's office the xrays showed no damage to the prothesis but couldn't see any damage to soft tissue. Now, two months later I am having many problems. Going up and down stairs very difficult, sometimes have to revert to going up/down one step at a time. Swells with pain and stiffness after bike excercise, walking (sometimes medium distance sometimes short distances), Driving (TKR left knee) with imobile left leg after 15 minutes or longer. Sometimes after being active then sitting (short or long sitting time) then trying to get up I find I can't move my leg in any way. Tension in any muscle of leg results in severe pain. Had to call my daughter-in-law to come help me get out of the chair in order to use the bathroom. Once up and slow walking I can diminish the situation either a little or a lot. Can sometimes walk even without the cane but usually after an event I use the cane. Next day my knee will be much better and the doctor cannot see the problem directly so does not know what happened or what to do about it. He says he has never encountered this problem before. He has a great reputation and is very experienced. I am very frustrated and don't know what to do. I am 77 years old, learning to ride a horse, am a special education teacher and substitute as much as I can. Want to keep going!