 Recent findings spanning the pre-, intra- and postoperative periods suggest that the development of PPP after TKR is a multi-factorial process, comprised of both neurophysiologic and psychosocial factors. Likely determinates include preoperative thermal pain sensitivity, anxiety, pain catastrophizing; and postoperative area of secondary mechanical hyperalgesia or hypoalgesia numbness. There is already agreement that the intensity of early acute postoperative pain is one of the factors predicting PPP. To date, most studies have examined the role of risk factors in isolation andor within a single domain, and no prospective study has comprehensively evaluated the interaction of neurophysiologic and psychosocial variables in the evolution of PPP following TKR. The lack of information regarding how neurophysiologic pathways and patient cognitiveaffective states interact over time following otherwise successful TKR has greatly undermined the understanding of PPP after TKR. 