Hi Rebecca
I'm guessing that it's the actual synovium behind the knees that's causing the problems rather than the replacements themselves? I had a few similar issues following a wrist replacement and had to have further surgery to drain a build up of fluid and some odd little bits of bone (can't remember what they called them, osteophytes, I think!) that remained after the initial op. Did the trick though and no further problems!
I haven't had a knee replacement but it was on the cards. The surgeon suggested a synovectomy to scrape away the solid synovial layer from behind the kneecap and that seemed to work. He told me it would only be a temporary fix but that was years ago and knee is still holding up despite being swollen constantly!
Surgery on knees is highly successful these days so perhaps a bit of fine tuning needed? Maybe a release of fluid, perhaps? Could you perhaps go back to see the surgeon who did the ops?
Going through all the discomfort of surgery to end up with problems is bad news. Replacement should actually be the end of it ... that's the point of the operation, less pain, more mobility! Hope you get a satisfactory solution to this. Take care,
Lyn x
PS Just read Diane's post. Surgeon told me that they don't often replace kneecaps as generally they don't suffer damage in the way that the actual joint itself does. Apparently kneecap replacement is a huge job and only undertaken if absolutely necessary. The infection angle is a possibility but I would have thought they'd have checked that before injecting steroid, my GP usually draws off a little fluid first to check it's clear.