Suggest Treatment For Swollen And Painful Knee And Legs

I have had half knee replacements which have left me with severe pains and swelling in leg and knees. Ops were 2years ago . I had X-rays which have shown marks all around lower part of leg just below knee. Have had lots of test to see if there were any infection but all test come back clear of any infection. My consultant can't explain what is wrong meantime I have to use my crutches every day and am on strong pain killers . Do you have any ideas what may be the problem surly something can be done.