Effects of Exercise and Education in Patients With Chronic Pain After Total Knee Replacement

Effect of Neuromuscular Exercise in Combination With Pain Neuroscience Education Compared to Pain Neuroscience Education Alone in Patients With Chronic Pain After Primary Total Knee Arthroplasty: A Randomized Controlled Trial

The purpose of the study is to investigate whether a 12-week neuromuscular rehabilitation program (NEMEX-TJR) combined with pain neuroscience education (PNE) provides greater pain relief, improvement in physical function and quality of life than PNE alone in a population of patients with chronic pain after primary total knee arthroplasty.

Hypothesis: Rehabilitation involving neuromuscular training and PNE will provide greater pain relief, improved function and improved quality of life compared to PNE alone at the primary endpoint, which is follow-up 12months after the start of the treatment.

Osteoarthritis is considered the most frequent cause of disability and pain in the elderly population, and the knee joint is one of the joints most commonly affected.

End-stage osteoarthritis is often treated with knee replacement, and total knee arthroplasty is considered an effective treatment for pain relief and improved function. However, several studies have reported less favorable outcomes after total knee arthroplasty, and systematic reviews found chronic pain after total knee arthroplasty at 12 months post-operative in 13-17% of the patients and chronic pain rates at 2-7 years post-operative varying between 8-27%. No randomized controlled trials evaluating exercise and pain education treatments to patients with chronic pain after total knee arthroplasty exists, and this highlights the need for evidence-based knowledge of which treatment should be considered for this population.

Inclusion Criteria:

• Body Mass Index (BMI) between 19-40
• Subjects with primary total knee arthroplasty due to osteoarthritis ≥ 12 months post-operatively
• For the index knee, duration of knee pain > 6 months
• For the index knee, the average daily pain score ≥ 4 (moderate-to-severe pain) over the last week prior to visit on a numeric rating scale

Exclusion Criteria:

• Specific reasons for chronic pain, such as loosening of implant, which requires revision surgery
• Secondary causes of arthritis to the knee, e.g. rheumatoid arthritis
• Surgery (including arthroscopy) of the index knee within 3 months prior to visit
• Injury to the index knee within 12 months prior to visit
• Recent history of acute pain affecting the lower limb and/or trunk
• Participation in other pain trials two weeks prior to this study
• Pregnancy
• Drug and alcohol abuse
• Previous neurologic illnesses or primary pain area other than knee, e.g. lower back, upper extremity pain or rheumatoid arthritis
• Lack of ability to adhere to protocol