You have to take more fibre, protein, variety of veg, 3-4 fruit servings in a day but in moderate amounts because of diabetes
, very sweet fruits like banana, mango, sitaphal etc are restricted, dry fruits especially wall nuts & flex seeds for omega 3 and virgin fats etc. You knee cartilage (cushion) is gone so you have to take some supplements to naturally make the cartilage, to prevent arthritis
. Even if it has come - it could be cured with right nutrition therapy.