I had a total right knee replacement in September 08 - 2 years ago. I am 71 years of age, and fairly active. Throughout the past 2 years my knee has felt at least 75% better than before the replacement, but not as good as I expected. Mr. Doctor just tells me to take Naproxen. In the past 6 months I have notice my knee buckeling 2 or 3 times a day. Never enough to cause me to fall, but definitely enough to cause me to reach out to grab something. My biggest concern is that this will increas and one day I will fall. Has anyone else expreienced this problem after knee replacement?