I had PKR about 3 years ago and things have been going good this last week I came down with Penuemonia feeling alot better on that part. But a couple of days before getting sick I noticed my knee would catch and then I would have to straighten it out to make it if you would say pop to get the catching feeling to go away. Now it is swollen and sore and it seems it has fluid in the knee, and is also when I am standing and straighten it out all the way it really hurts just below the knee cap all the way to the middle of the knee joint. I am also having pain at the back of my leg at the knee and some calf pain... At first I was thinking may the infection from the pneumonia possibly had gone to the replacement but it is not hot and I have been on Levaquin for 5 days now for the pneumonia... I have not injured it that I know of so this all the sudden is frustrating me. But I know from the past I don't have to injur myself for my knees to act up.. I have severe OA reason why they did the replacement and I am only 47 I have been dealing with OA since I was 23 so scopes etc I have had my share... Didn't know what this new symptoms could be.. I thought cyst, synovial inflamation or has something come loose or what. the procedure they did was put a plastic button on the back of the knee cap and titanium plate at the end of my femur. Has anyone had this problem several years after PKR or could this just be a flair up. Just really frustrated because things have been going really well. Thanks in advance for any advice.