PTGS2 and osteoarthritis, knee: Knee osteoarthritis (OA) patients suffer from joint pain and immobility, which isusually treated by nonsteroidal anti-inflammatory drugs (NSAIDs) and physicaltherapy, with total knee arthroplasty (TKA) as an end-stage diseasesolution.1,2Over the years, several disease-modifying OA drugs came to attention.3 Selective cyclooxygenase-2 (COX-2) inhibitors are a type of disease-modifyingOA drugs and are investigated for their effect on the inhibition of prostaglandins(PGs).