I found that the only thing that helps with arthritis pain is reducing inflammation- which I have chronically (very high ESR and CRP every blood test), and the best way I've found to do that is to fast. By giving your system a rest, it can heal you. And you also lose weight which helps everything. By eating food that suits you (ie- for many, avoiding gluten and dairy helps) that will reduce inflammation in your system. It won't repair your knee but it might help with the pain.