A randomized, controlled trial on the effect of anesthesia on chronic pain after total knee arthroplasty

Aim: The study sought to evaluate the influence of anesthesia on chronic pain after total knee arthroplasty (TKA). Methods: This was a single-center, randomized controlled study, with patients receiving a spinal anesthetic (SP) alone or a general anesthetic (GA) with femoral block, with follow-up at 3 and at 6 months. The primary outcome was the WOMAC(R) score at 6 months. Results: 199 patients were enrolled. Group SP had better function (WOMAC: GA: 16.9 vs SP: 14.4, p = 0.015) and less pain (WOMAC pain: GA: 3.04 vs SP: 2.69, p = 0.02) at 3 months, but not at 6 months. Overall, 11% of patients had chronic postsurgical pain (CPSP), with Group GA having a higher incidence of CPSP at 6 months. Neuropathic pain increased during the follow-up and was more common in patients with CPSP. Conclusion: An SP reduces pain and incidence of CPSP after TKA. Clinical Trial Registration: NCT04206046 (ClinicalTrials.gov) Plain language summary Patients who have knee replacement surgery are at risk of remaining in significant pain even up to one year after surgery. Our study aims to look into the potential of reducing this risk by comparing two common forms of anesthesia. 199 patients were randomized to either have a spinal anesthetic (SP) or a general anesthetic with a femoral nerve block. Patients were then followed-up for 6 months, and then asked to report on a validated functional and pain scoring system (WOMAC(R)). Patients who had had an SP had better function and less pain at 3 months after surgery, but not at 6 months. The incidence of chronic pain at six month seems to be less with an SP