Effects of pain neuroscience education combined with blood flow restriction training on chronic postoperative pain following total knee arthroplasty: a randomized controlled trial protocol.

INTRODUCTION: Chronic postsurgical pain (CPSP) remains a major clinical challenge following total knee arthroplasty (TKA), with psychological maladaptation and persistent neuromuscular dysfunction considered key contributors to ongoing pain and disability. Pain neuroscience education (PNE) may improve maladaptive pain cognitions, whereas blood flow restriction training (BFRT) can enhance muscle function and induce exercise-related hypoalgesia. Although both interventions have shown potential benefits in chronic pain rehabilitation, no randomized controlled trial has investigated the combined efficacy of these two interventions in patients with CPSP after TKA. This study aims to determine whether combined PNE + BFRT produces greater improvements in pain and function in this population. METHODS AND ANALYSIS: This study is a single-blind, four-arm, parallel-group randomized controlled trial. A total of 148 participants will be randomly assigned (1:1:1:1) to the Control, PNE, BFRT, or combined PNE + BFRT group. PNE will be delivered in two structured sessions. BFRT involves a 12-week supervised low-load resistance training program. The primary outcome is the group-by-time interaction effect on KOOS₄ over time. Secondary outcomes include pain intensity (NRS), global perceived effect, pain distribution, psychological measures (HADS, PCS), physical performance (40-m fast-paced walk test, stair climb test, and 30-s chair stand test), and neuromuscular strength. Assessments will be conducted at baseline, post-intervention (12 weeks), and at 12-week, 24-week, and 36-week follow-ups. Data will be analyzed using linear mixed-effects models under the intention-to-treat principle. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the Ethics Committee of the Chengdu Sport University, with permission number CDSUEC2026- 177. This study has been registered with the Chinese Clinical Trial Registry (ChiCTR2600125544). Written informed consent will be obtained from all participants prior to enrollment. TRIAL REGISTRATION NUMBER: Chinese Clinical Trial Registry ChiCTR2600125544, registered on May 28, 2026.