20% of all patients are dissatisfied with the treatment outcome after primary total knee arthroplasty. Preoperative mental factors favor the occurrence of postoperative complications. Unfortunately, the use of psychotherapeutic methods according to Knie-Tep has hardly been investigated. This study examined the effect of pain psychoeducation on treatment outcome after primary total knee arthroplasty. In N = 75 patients, quality of life and knee-specific functionality were recorded five days before and three months after surgery, as seen by the patient and physician. The participants in the intervention group received pain psychoeducation four days postoperatively, while the participants in the comparison group received no additional information. Patients with education had significantly less pain than patients without pain psychoeducation three months after primary total knee arthroplasty (p <0.01). In terms of postoperative quality of life, the groups did not differ from each other.