BACKGROUND: We previously reported that extending an overnight continuous posterior lumbar plexus nerve block to 4 days after hip arthroplasty provides clear benefits during the perineural infusion in the immediate postoperative period. However, it remains unknown whether the extended infusion improves subsequent health-related quality of life. METHODS: Patients undergoing hip arthroplasty received a posterior lumbar plexus perineural infusion of ropivacaine 0.2% from surgery until the following morning, at which time patients were randomized to continue either perineural ropivacaine (n = 24) or normal saline (n = 23) in a double-masked fashion. Patients were discharged with their catheter and a portable infusion pump, and catheters were removed on postoperative Day 4. Health-related quality of life was measured using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index preoperatively and then at 7 days and 1, 2, 3, 6, and 12 mo after surgery. The WOMAC evaluates three dimensions of health-related quality of life, such as pain, stiffness, and physical functional disability (global score of 0-96, lower scores indicate lower levels of symptoms or physical disability). For inclusion in the primary analysis, we required a minimum of three of the six timepoints, including Day 7 and at least two of Months 3, 6, and 12. RESULTS: The two treatment groups had similar global WOMAC scores for the mean area under the curve calculations (point estimate for the difference in mean area under the curve for the two groups [extended infusion group-overnight infusion group] = 0.8, 95% confidence interval: -5.3 to + 6.8 [-5.5% to + 7.1%]; P = 0.80) and at all individual timepoints (P > 0.05). CONCLUSIONS: This investigation found no evidence that extending an overnight continuous posterior lumbar plexus nerve block to 4 days improves (or worsens) subsequent health-related quality of life between 7 days and 12 mo after hip arthroplasty.