OP: What I do and I have a lot of years of knee issues that I've talked about here...the knee has been pretty damaged with OA and then a nasty infection that went undiagnosed for months..long story.
I was given a arthroscopic clean out while in hospital last year and I think it's worse from that clean out...they just clean out more cartilage each time....knee replacements are likely after all these arthroscopic jobs.
What I hear all the time from a doctor here is that cortisone "softens" cartilage. These may help but very temporary and then the longterm damage.
Since you are so young with all the issues, replacement may be your way....but if you could look into PRP/Stem Cells, they could save the knee...
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I've come to believe the more surgeries, the more damages done. Since my hip replacement in 2010, my whole right side of body is a mess. It was right hip.
What I use to save my knee from more surgery is: Cosamin DS, Higher Doses Omega 3's and will be adding Curcumin soon again.
Did you do a lot of sports? My grandkids do and I think about their future joints..but can't control their lives. I moved a lot in my live but didn't go overboard but still damage.
I'm far from any doctor but have been working with my health and headed to 80 this year. Good luck to you.