100 patients enrolled in this study to determine the effects of specific nonsteroidal anti-inflammatory drugs in the treatment of osteoarthritis of the knee. High and low doses of celecoxib, diclofenac and ibuprofen were administered for 2 weeks prior to TKA operation. The results taken just before the operation suggest that Interleukin-6 (IL-6), tumor necrosis factor-alpha and vascular endothelial growth factor concentrations were decreased with every drug therapy excluding the low dose of ibuprofen which only decreased IL-6. Western Ontario and McMaster University index scores improved with all drugs and dosage levels.