Exercise and Pain Neuroscience Education for Patients With Chronic Pain After Total Knee Arthroplasty: A Randomized Clinical Trial

Abstract

Importance: Up to 20% of patients develop chronic pain after total knee arthroplasty (TKA), yet there is a scarcity of effective interventions for this population.

Objective: To evaluate whether neuromuscular exercise and pain neuroscience education were superior to pain neuroscience education alone for patients with chronic pain after TKA.

Design, setting, and participants: A superiority randomized clinical trial was conducted at 3 outpatient clinics at Aalborg University Hospital in Denmark. Participants with moderate-to-severe average daily pain intensity and no signs of prosthesis failure at least 1 year after primary TKA were included. Participant recruitment was initiated on April 12, 2019, and completed on October 31, 2022. The 12-month follow-up was completed on March 21, 2023.

Interventions: The study included 24 sessions of supervised neuromuscular exercise (2 sessions per week for 12 weeks) and 2 total sessions of pain neuroscience education (6 weeks between each session) or the same pain neuroscience education sessions alone. The interventions were delivered in groups of 2 to 4 participants.

Main outcomes and measures: The primary outcome was change from baseline to 12 months using the mean score of the Knee Injury and Osteoarthritis Outcome Score, covering the 4 subscales pain, symptoms, activity of daily living, and knee-related quality of life (KOOS4; scores range from 0 to 100, with higher scores indicating better outcomes). The outcome assessors and statistician were blinded. All randomized participants were included in the intention-to-treat analysis.

Results: Among the 69 participants (median age, 67.2 years [IQR, 61.2-71.9 years]; 40 female [58%]) included in the study, 36 were randomly assigned to the neuromuscular exercise and pain neuroscience education group, and 33 to the pain neuroscience education-alone group. The intention-to-treat analysis showed no between-group difference in change from baseline to 12 months for the KOOS4 (7.46 [95% CI, 3.04-11.89] vs 8.65 [95% CI, 4.67-12.63] points; mean difference, -1.33 [95% CI, -7.59 to 4.92]; P = .68). Among the 46 participants who participated in the 12-month assessment in the 2 groups, 16 (34.8%) experienced a clinically important improvement (a difference of ≥10 points on the KOOS4) with no between-group difference. No serious adverse events were observed.

Conclusions and relevance: In this randomized clinical trial, the results demonstrated that neuromuscular exercises and pain neuroscience education were not superior to pain neuroscience education alone in participants with chronic pain after TKA. Approximately one-third of the participants, regardless of intervention, experienced clinically important improvements. Future studies should investigate which patient characteristics indicate a favorable response to exercises and/or pain neuroscience education.

Trial registration: ClinicalTrials.gov Identifier: NCT03886259.

Figure 1.. Patient Flow Diagram From Baseline to the 12-Month Follow-up

PNE indicates pain neuroscience education.

Figure 2.. Changes in the 4 Knee Injury and Osteoarthritis Outcome Score Subscales (KOOS₄)

The KOOS₄ primary outcome includes the subscales pain, symptoms, function of daily living, and knee-related quality of life; scores range from 0 to 100, with higher scores indicating better outcomes. Data points are means; error bars represent 95% CI. PNE indicates pain neuroscience education.

Figure 3.. Individual Changes in the 4 Knee Injury and Osteoarthritis Outcome Score Subscales (KOOS₄) From Baseline to the 12-Month Follow-up

The KOOS₄ primary outcome includes the subscales pain, symptoms, function of daily living, and knee-related quality of life; scores range from 0 to 100, with higher scores indicating better outcomes. Positive scores indicate improvements in KOOS₄, and negative scores indicate a decline in KOOS₄. PNE indicates pain neuroscience education.