I have had both knees replaced the first 9 months ago and the second 5 months ago and I'm struggling with every step also. Like you doctor says I'm doing great.. Really don't understand how he comes to that conclusion when I am telling him how limited my life has become. Rehab done up to 3 times a week steroid injections, and nerve ablution. The pain is accompanied by a feeling of extreme heaviness in my legs like I've been dragging a 50lb lead ball chained to both legs, and they both swell within the first 200 steps a day. I understand your frustration and am searching for something to give me hope. Best wishes to you on your journey.