Background: Total Knee Arthroplasty (TKA) is a common and generally effective procedure performed mainly due to advanced osteoarthritis, pain, physical disability and reduced quality of life. However, approximately 20% of the patients respond poorly to the surgery and chronic pain and disability following TKA remains a major health burden for many patients. Among the most well documented and powerful psychological predictors of poor outcome following TKA is pain catastrophizing. Recent research has shown that patients with these thoughts are at higher risk of having persistent pain and lower physical function after the operation than patients with low levels of pain catastrophizing before TKA. There is high need of developing treatments aimed at improving self-management for this group of patients and the aim of this study is to investigate the effectiveness of a patient education in pain coping on physical function and pain among patients with high pain catastrophizing score before a TKA. Methods: This study is a two-arm parallel group trial design including 56 patients with high levels of pain catastrophizing referred for total knee arthroplasty due to osteoarthritis. Patients eligible for participation will be randomized into the two arms, usual care or usual care and patient education. Usual care consists of operation and standard rehabilitation. The patient education consists of 7 individual sessions focusing on pain behavior and pain coping managed by a physiotherapist. Three before the operation and four after. Measurements will be taken at baseline before the operation and 3 and 12 months after the operation. Primary outcome will be pain after 12 months measured with VAS (Visual Analogue Scale). Secondary outcomes include physical function and activity, quality of life, pain management and psychological factors. Discussion: Only few studies have evaluated the effectiveness of psychological interventions on patients with high levels of pain catastrophizing before the operation. This trial will provide evidence for the effectiveness of a cognitive-behavioral patient education delivered by physiotherapists and may provide better functional outcome and less pain for a vulnerable group of TKA patients. We expect that the results can provide important new knowledge to the current care recommendations.