It's all fine talking about diet etc, etc, but she's the one in pain.
We went through the injections. In the end they just speed up the break down of the knee by masking the problem, and allowing the joint to wear faster.
In the end it's your partner's pain, you should really do what she wants or requires.
My wife has had both knees replaced. She has minimal pain now (right knee only), which could yet improve because it's not yet a year since it was done.
After she had her first knee replaced, they asked about her second knee, and she had no hesitation at all. Which tells you all you need to know.
I can assure you that 'this' is not playing out, and people assuming are certainly living out their own prejudices.
We've been married more than 25 years, the property in Chiang Mai, we've owned more than 20 years. We own plenty of properties here in the UK which we let out.
So perhaps we could hold up with the newbie horror stories, and stick with the original question.