Is There a Difference in Factors Affecting Rest Pain and Pain Intensity during Movement at 1 Year Post–total Knee Arthroplasty?

Abstract

Objectives: Total knee arthroplasty (TKA) effectively improves motor function and reduces pain in patients with osteoarthritis (OA). However, recent research emphasizes the distinction between rest pain and post-TKA pain due to their impact on treatment and recovery. This study aimed to identify factors associated with rest pain and pain intensity during movement 1 year post-TKA. Methods: A total of 126 individuals (103 females, average age: 72.3 ± 8.1 years) undergoing TKA were included. All variables were assessed 1 year postoperatively. Multiple regression analyses were performed using rest pain and pain intensity during movement as dependent variables. Independent variables included age, sex, body mass index (BMI), short form of Central Sensitization Inventory (CSI-9) score, the Fremantle Knee Awareness Questionnaire (FreKAQ) score, inappropriate femorotibial angle, and β angle. Results: Multiple regression analyses demonstrated that FreKAQ score was a significant independent predictor for both rest pain (β = 0.583, 95% confidence interval [CI]: 0.72–1.34) and pain intensity during movement (β = 0.486, 95% CI: 0.72–1.52). Additionally, CSI-9 score (β = 0.183, 95% CI: 0.02–0.93) and the β angle (β = −0.218, 95% CI −3.17 to −0.60) were significant independent predictors for pain intensity during movement only. Conclusions: Specific treatments addressing disturbed body perception may benefit patients with rest pain. Conversely, pain intensity during movement was found to be influenced by various factors, including coronal alignment of the knee joint, central sensitization (CS)-related symptoms, and disturbed body perception. This suggests a need for more comprehensive treatment strategies for pain intensity during movement.