<qa>  What is the risk factor for preoperative thermal pain sensitivity?These risk factors are preoperative thermal pain sensitivity, pain anxiety and catastrophizing; postoperative area of secondary mechanical hyperalgesia or hypoalgesia numbness and pain intensity. PPP for this study will be defined as pain in the operated knee at six months after TKR, with other causes of pain excluded and reported intensity on 0-10 Numerical Response Scale NRS scale of 4. The study will also evaluate the relationship of PPP incidence with the severity of functional impairment. This is a single-site prospective clinical investigation of 300 consented OA patients undergoing primary, unilateral TKR. 