PROSAP-A is a perioperative randomized, controlled trial with a 12-month follow-up period after total knee arthroplasty (TKA) or total hip arthroplasty (THA), aiming to investigate both acute and long-term postoperative effects of preoperative sleep-promotion. Participants with clinically significant insomnia symptoms will be randomized to a brief, hybrid version of cognitive behavioral therapy for insomnia (CBT-I) or sleep education therapy, administered over a 4-week period, prior to surgery. The primary objective is to evaluate effects of preoperative sleep-promotion on acute postoperative pain control. Secondary objectives include evaluation of postoperative sleep, recovery, mental health, cognitive function and alterations in blood biomarkers.