Inclusion Criteria:  Patient has a Pain Catastrophizing Score >16 55 years of age and older. English speaking. Has a smartphone (iPhone). Able to swallow oral medications. No continuous daily opioid as defined as more than 15 days in the 30 days before surgery. Undergoing TKR surgery. Patients who are willing and able to comply with scheduled visits and study procedures.  Exclusion Criteria:  Diagnosed with Opioid Use Disorder (OUD). Actively using illicit drugs. Allergy to opioids Older than 85 years