The association between chronic pain and central sensitization following total knee replacement: A retrospective cohort study

Background: Pain still persists in 20% of patients who have had total knee replacement (TKR) surgery. It is important to investigate the reason for the persistent pain after surgery and related factors. This study aimed to elucidate any connection between central sensitization and ongoing pain after knee replacement surgery and other associated factors. Methods: The population was composed of 182 patients who had undergone TKR, and in follow-up visits from 1 mo to 2 yr after the operation, they were evaluated using the Pressure Pain Threshold (PPTs), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Central Sensitization Inventory (CSI), the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS), the Beck Depression Inventory (BDI), and the painDETECT test. Results: The mean follow-up period was 6.84 +/- 4.10 (1-24) months. According to the postoperative LANSS score, neuropathic mechanisms were responsible for pain in 48.4% (88/182) of the patients. CSI showed central sensitization in 41.2% (75/182) of the patients (CSI score >= 40). Patients whose pain was not associated with neuropathic mechanisms (LANSS score <12 or painDETECT score<19) saw more benefit from surgery (P<0.001). Additionally, pain relief after TKR was more prevalent in patients whose CSI score was <40 points (P<0.001). Conclusions: This study showed that neuropathic mechanisms and central sensitization are important sources of persistent pain in patients who have had total knee replacement. Evaluation of central sensitization and neuropathic mechanisms may play an important role in management of pain