Effectiveness of a physiotherapist delivered cognitive-behavioral patient education for patients who undergoes operation for total knee arthroplasty: a protocol of a randomized controlled trial

Total Knee Arthroplasty (TKA) is a common and generally effective procedure and most of the operated patients have less pain and higher functional ability after the surgery [1]. However, some patients respond poorly to the surgery and chronic pain following TKA remains a major health burden for many patients [2]. “Poor” outcome following TKA is due mainly to disabling pain and impaired function [3, 4]. Thus, persistent knee pain was reported 12 months after TKA in 16.4% of the patients by Baker et al. who followed 9417 patient’ pain using the Oxford Knee Score (OKS) [3]. Similar pain results were reported by Nilsdotter et al. [5]. Most recently, in a systematic review Beswick and colleagues stated that 20% reported persistent function-limiting pain 6 months or more following a TKA, despite an apparently normally functioning prosthesis [4]. Routinely screening for patients at high risk for persistent pain after the surgery is suboptimal and not common practice [6]. This practice has potential to change because resent research shows that we are able to identify several psychological predictors of poor outcomes after knee arthroplasty. From the literature on non-surgical chronic pain the evidence suggests that pain disability does not result solely from the severity of pain but is largely influenced by patients’ adjustment and interpretation to their pain [7, 8]. Among the most well documented and powerful psychological predictors of poor outcome following TKA is pain catastrophizing [9]. Pain catastrophic thoughts are related to pain rumination, pain magnification and helplessness in the face of pain. New 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 [2, 10‐14].

Cognitive Behavioural Therapy (CBT) is one of the most widely accepted models in the field of pain psychology and the biopsychosocial approach of CBT focuses on the complex interaction between psychological (mood, personality, behavior, cognition etc.), social (cultural, familial, socioeconomic, medical, etc.) and biological (genetic, biochemical, etc.) factors. The biopsychosocial model assumes that health problems are hardly ever limited to just one domain of human experience but by multiple domains of human experience. CBT is a treatment that helps patients understand the thoughts and feelings that influence behaviors. CBT consists of a cognitive aspect and a behavioural aspect. The cognitive aspect is based on Becks cognitive model [15]: the way that individuals perceive a situation is more closely connected to their reaction than the situation itself. A person’s cognition has impact on their mood and emotions, their bodily reactions and their behavior. This is illustrated in Fig. 1. The second part of cognitive behavior therapy focuses on the actual behaviors that are contributing to the problem. The client begins to learn and practice new skills and one of the aims is to decrease maladaptive pain behaviors. The goal of CBT is to identify maladaptive thoughts and consequently change them into more realistic and constructive thoughts to modify feelings and behaviour and thereby the experience of pain [15, 16]. CBT protocols are typically delivered by psychologists but they are often not integrated into primary care where most of the patients are seen. It may be beneficial to use a single health care professional to deliver the patient education in pain coping and in connection with the operation where the patients meet the physical therapist several times. Potential advantages of using only one health care person may be a reduced overall cost to the health care system, increased opportunity of receiving the treatment and an experience of a more consecutive treatment because the patient has contact to fewer health care persons. Physical therapists have a history of teaching patients about pain and pain coping, and given their expertise with using physical treatments to treat patients pain and their experience in using the biopsychosocial approach in their treatment, physical therapists is a qualified choice to deliver a patient education in pain coping [17, 18].

Psychological interventions as CBT that train patients in pain coping produce significant reductions in pain and improvements in self-efficacy and psychological well-being in individuals with knee osteoarthritis (OA) [19‐23]. However, there has been only been very few attempts to reduce pain by using a CBT approach in a population of patients with high preoperative pain catastrophizing score. In 2011 Riddle et al. published the results of a quasi-experimental study. They found that patients who had received training in pain coping skills had a greater reduction in pain and pain catastrophizing 2 months after TKA. Furthermore, they had a larger improvement in physical function measured with Western Ontario and McMaster Osteoarthritis Index (WOMAC) compared to patients in the control group [24]. On basis of this study Riddle et al. has published a study protocol describing a clinical randomized trial [25]. Since there have only been few studies evaluating the effect of psychological interventions on knee pain and no randomized controlled trials evaluating the effect on patients with high levels of pain catastrophizing, well designed randomized controlled trials to determine the effectiveness of such interventions are needed. Our study will supplement the trial from Riddle et al. but there will also be several differences i.e. the study from Riddle et al. will test a telephone-based pain coping skills training contrary to our study where the patients come to the hospital and meet a physiotherapist at all training sessions. Further, in our study a larger part of the sessions are placed preoperative instead of postoperative. There is need for studies examining how to improve care and treatment for patients with poor pain coping at high risk of chronic pain after the operation. Our study aims to target this need. Our primary aim is to investigate the effectiveness of a patient education in pain coping on pain among patients with high pain catastrophizing score before a TKA. The secondary aims of the study are to investigate the effectiveness on physical function, physical activity, quality of life and pain catastrophizing. We hypothesize that patients with high pain catastrophizing scheduled for TKA who participate in a patient education in pain coping will experience 1) lower pain intensity 2) a higher physical function 3) a higher self-reported quality of life 4) and a lower pain catastrophizing score after the operation than patients who do not participate in patient education.