What are the best treatment options for severe arthritis in Thailand, especially concerning knee replacements?

Not visa advice but medical. My Thai g/f has bad arthritis in her knees, has anyone on here had a similar issue in thailand ? She’s 59 and has been countless times to various Thai hospitals for treatment and it’s always the same. take blood, X-rays, injections etc, I said she needs a knee replacement but she and the doctors are against it, she’s in constant pain from it and has tried most of the alternative fixes, creams,patches,injections,massage,etc non working, just had 6 visits to a clinic in Bkk for treatment and things are still the same,. I’m reluctant to pay thousands of baht for a private knee opp in a Bkk hospital when she as a Thai citizen can get it for free or little cost at a public Thai hospital,and before you start calling me a cheap Charlie I’ve thrown thousands of baht at this problem for years to no avail, fed up of going around in circles and need it sorting once and for all, any advice on costs of doing it private/public and the outcome at the end Tia,.