2.1. Patients
opioid abuse, multimodal basal pain, cognitive impairment
One hundred forty-nine patients scheduled for primary TKA at St. Olavs hospital, Trondheim University Hospital, Norway, were included in the study. The inclusion took place between November 26, 2015, and November 7, 2018. Patients were recruited by an anesthesiologist at the outpatient preoperative clinic. The inclusion criterion was an age of 18 to 80 years. The exclusion criteria were cognitive impairment, not reading/speaking Norwegian, no cellphone or wireless Wi-Fi connection at home, use of drugs (e.g., antidepressive drugs or angiotensin II receptor blockers), or medical conditions that, according to the Norwegian Pharmaceutical Compendium, conflicted with one or more of the study drugs or any of the multimodal basal pain medications given in the study. Patients with regular opioid use or previous opioid abuse were excluded. Pregnant or breastfeeding women and patients scheduled for general anesthesia were not included in the study.