 This is a multicenter when more than one hospital or medical school team work on a medical research study, randomized the study drug is assigned by chance, open-label all people know the identity of the intervention, comparative study to compare the efficacy of tramadol hydrochloride plus acetaminophen maintenance with that of NSAIDs maintenance in participants whose pain was relieved after the add-on treatment of tramadol 37.5 milligram mg plus acetaminophen 325 mg to NSAIDs. All participants will receive tramadol hydrochloride 37.5 mg plus acetaminophen 325 mg, 1 to 3 tablets per day along with NSAIDs meloxicam 7.5 mg or 15 mg once daily or aceclofenac 100 mg twice daily from Day 1 to Day 28, and participants will be randomly assigned into 2 treatment groups at Day 29 if the numerical rating scale score less than or equal 4. Tramadol plus acetaminophen group will receive 1 or 2 tablets containing tramadol 37.5 mg plus acetaminophen 325 mg 4 times daily maximum daily dose will be 8 tablets from Day 29 to Day 85 and NSAIDs group will receive either meloxicam 7.5 mg or 15 mg per day or aceclofenac 100 mg twice a day from Day 29 to Day 85. The efficacy will be evaluated on Day 1, Day 29, Day 57 and Day 85. The primary efficacy end point will be assessed through change in Western Ontario McMaster Universities Osteoarthritis Index WOMAC total score from Day 29 to Day 85. Participants safety will be monitored throughout the study. 