Dissatisfaction is still an important problem in a small but important group of patients who undergo total knee arthroplasty. This study was designed to evaluate the effectiveness of showing patients the change in their standing posture, before and after total knee replacement, using standing photographs (anterior, posterior, and lateral view), on improving self-reported quality of life and satisfaction. Full-length lower extremity radiographs and standing photographs were obtained prior to total knee replacement and 6 months after surgery in the study group. In the control group, radiographs and photographs were not obtained. The hip–knee–ankle angle and mechanical axis deviation were compared between the two limbs and two groups. The changes in the following outcome measures were evaluated from baseline to 6 months after surgery: Short Form-36 Survey, Knee Injury and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, Oxford Knee Score, and Knee Society score. Postoperative measures were also compared before and after showing patients their standing photographs, and between two groups. The study and control groups included 71 and 44 patients, respectively, with unilateral or bilateral knee osteoarthritis (Kellgren–Lawrence Grade 3 or 4), with a mean age of 66 years. All patients had a varus malalignment, with significant improvement in postoperative limb alignment (p < 0.001). All self-reported outcome measures improved after surgery (p < 0.05), with the exception of mental health in the Short Form-36. Self-reported scores further improved after patients seeing their standing photographs (p < 0.05), with the exception of mental health and social role functioning. There were also significantly improved scores in the study group than control group after showing photographs (p < 0.05). Showing patients the pre-to-postoperative change in their standing posture might be an easy-to-administer method to improve patient satisfaction with the outcome of total knee replacement and self-reported quality of life. The Level of Evidence for this study is four.