Effectiveness of PNE on pain after TKA

Rationale: Total knee arthroplasty (TKA) is a widely used operation for osteoarthritis, with high acute and chronic pain scores. Pain neuroscience education (PNE) focuses on teaching people more about pain from a neurobiological and neurophysiological perspective and has shown effectiveness in reducing pain. More knowledge about pain could contribute to improved physical quality of life and reduction of catastrophizing thoughts.
Objective: The main objective is to compare the effectiveness of two sessions PNE versus care as usual on pain levels 3 months after surgery in patients undergoing TKA.
Secondary objective is to explore the effectiveness of two sessions PNE versus care as usual on pain levels 12 months after surgery in patients undergoing TKA. Third objective is to explore the effectiveness of two sessions PNE in comparison to care as usual on physical functioning, stiffness, health related quality of life 3 and 12 months after surgery. The fourth objective is to explore the influence of the psychological variables attention to pain, catastrophizing, anxiety and depression on treatment (PNE) outcome.
Study design: A prospective, single center, two-arm, parallel group, assessor blinded, randomized controlled trial at Tergooi hospital (Hilversum).
Study population: Patients aged 18 or older scheduled for primary TKA surgery are eligible for participation in the study. A sample of 76 patients will be randomly assigned to either PNE or usual care.
Intervention: A pre-operative and a post-operative educational session of respectively 45 and 30 minutes by a physical therapist about the neuroscience of pain, accompanied by an evidence-based booklet.
Main study parameters/endpoints: The primary outcome will be the change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale score 3 months following surgery. A variety of secondary clinical outcomes will also be evaluated.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The goal of the study is to compare usual care with usual care with two additional PNE sessions. The patients in our trial will be subjected to one of these conditions. It is hypothesized that the participants randomized to the PNE group will benefit from the intervention, since it is proven to have a positive effect on pain. Given the nature of the intervention, it is not plausible that participation will lead to an increased health risk.
In all participating patients, questionnaires will be conducted by telephone at 4 different time points (4-8 weeks pre-operative and 2 weeks, 3 and 12 months post-operative), which will take 30 minutes additional time per time point. In the experimental group, patients will also be subjected to two PNE sessions with a physical therapist. The pre-operative session will last 45 minutes and the post-operative session will last 30 minutes.

Our primary research hypothesis is that pain scores in our PNE intervention group will be lower than the pain scores in the care as usual group at 3 months after surgery, measured by the WOMAC pain score.

4 time points: 4-8 weeks pre-operative and 2 weeks, 3 and 12 months post-operative

PNE is an educational strategy used by physical therapists that provides information regarding the underlying neurophysiology and neurobiology processes involved in pain experience. In longer lasting pain complaints, the problem is not only the tissue damage or disease, but also processes in the spinal cord and in the brain as well (Moseley & Butler, 2015). In the case of chronic pain, the brain assumes that there is still a risk of tissue damage and so it continues to produce pain. The goal of PNE is to facilitate the reconceptualization of pain from a direct measure of tissue damage, to a complex human experience that serves a protective role. Achieving this reconceptualization changes the very experience of pain itself. The desired outcome of this educational intervention is pain reduction, as well as increased engagement in active pain treatment strategies i.e. graded activity, and increased social engagement.
The PNE intervention in this study will contain 2 face to face sessions with a specialized physiotherapist and a written manual (Nijs, 2011). During the first session, the view of the patient on his pain and the pain beliefs will be assessed with standardized questions. Misconceptions about pain will be traced and the trainer will provide patient specific knowledge on pain neurophysiology. In the second session, after surgery, the application of the gained knowledge on pain neurophysiology in daily practice will be discussed.