Fluid retention after a knee replacement

Hi everyone! I had a tkr October of 22. Everything was going great until my knee started retaining fluid 6 months after. I had an aspiration performed & was checked for infection. None was found. Several months later I had another aspiration performed & things were good for 2 months. No tightness, pain until it filled with fluid again. I have been to 3 orthopedic doctors, they all look at me like I have some rare disease & have no clue what is causing this. Last doctor told me to change my way of thinking & accept that this is as good as its going to get. REALLY! Has anyone experienced this or know of someone. Any help would be appreciated.