HI, thanks for using healthcare magic Severe OA can be very painful in some cases. The definite treatment option , if it is very severe would be knee replacement. Other than this, treatment would involve pain management and physiotherapy to strengthen the muscles around the knees (this helps with stabilization and improves pain). There are different types of pain killers and you can combine oral medication with topical agents such as voltaren gel. Oral medication consists of paracetamol, ibuprofen, naproxen, cataflam, celebrex, arcoxia, tramadol, hydrocodone, oxycodone Your doctor may combine pain medication from different drug families. I Hope this helps