There’s no cure for osteoarthritis as yet, but there are a number of treatments that can help ease symptoms and reduce the chances arthritis becoming worse...options are analgesics, NSAIDs,intraosseous steroid injection and hyaluronic acid injections,Physiotherapy like strengthening exercises etc ....Regarding diet - have small multiple meals instead of 3 big meals, eat food rich in proteins and fibres like egg white boiled chicken vegetables fruits pulses, avoid carbohydrate rich foods like rice curds oily foods sweets ghee and other junk food...good luck.