Inclusion Criteria:  Patients who were decided to undergo total knee replacement surgery with the diagnosis of osteoarthritis, Patients who will undergo elective surgery Patients who will undergo unilateral total knee replacement surgery for the first time Patients who can be communicated verbally Patients without any psychiatric disease Patients who use smartphones and agree to participate in the study  Exclusion Criteria:  Patients under the age of 18 Patients who have had previous total knee replacement surgery Patients who underwent total knee replacement with emergency surgery Patients who will undergo bilateral total knee replacement surgery Patients with a previous psychiatric diagnosis Patients with verbal communication disorders