IRCT2015101224484N1 IRCT 2016-03-15 Vice Chancellor for Research of Tabriz University of Medical Sciences Self-efficacy and pain control in the patients undergoing total knee arthroplasty Randomized controlled trial of comparison of the self-efficacy and pain control in the patients undergoing total knee arthroplasty with and without empowerment program 2016-03-20 anticipated 98 Complete https://irct.ir/trial/20654 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Supportive, Other design features: The person who collects data of outcome variables, doesn't know which patient belongs to which group. Participants are selected using convenience sampling and randomly allocated to two groups of intervention and control by randomization allocation software. N/A Knee arthroplasty. Intervention 1: In the intervention group, an empowerment program based on Linton cognitive-behavior and Bandura behavior changing models will be used which is implemented for 6 weeks (one session before surgery and 5 sessions after surgery). In control group there will be no intervention. Intervention 2: The control group receives no intervention.