What are the factors of residual pain after uncomplicated TKA?

Purpose Residual pain during activities of daily living and/or at rest is a major cause of a patient's dissatisfaction after total knee arthroplasty (TKA). The management of a painful TKA, which has no obvious clinical or radiological explanation, requires further investigation with more sensitive imaging modalities (CT scan and bone scan) and hematological tests. It is often challenging for the physician to determine what level of pain warrants these more complex and expensive medical examinations. A precise knowledge of the natural history of postoperative pain following TKA is therefore of fundamental importance. Methods We reviewed the literature and highlighted the studies that investigated the evolution of pain after uncomplicated TKAs and the impact of demographic and psychosocial variables on a postoperative painful TKA. Results Factors that are associated with a more painful knee include female sex, a younger age at the time of surgery, and a higher than normal depressive or anxiety state. In particular, the Pain Catastrophizing Scale (PCS), a scale that quantifies a patient's negative or exaggerated orientation to pain, appears to significantly influence a patient's outcome after TKA. Conclusion The identification of these high-risk patients is critical so that a surgeon can provide detailed preoperative education in order to give these patients a realistic expectation of their possible satisfaction following TKA. Level of evidence V.