['Intrathecal morphine and psoas compartment block represent two accepted techniques to provide postoperative analgesia after hip arthroplasty. We designed a prospective, randomized, single-blinded study to compare these two techniques.', "Patients scheduled for primary hip arthroplasty under general anesthesia were randomized to receive either an intrathecal administration of 0.1 mg morphine (Group I, n = 27) or a psoas compartment block with ropivacaine 0.475% 25 mL (Group II, n = 26). Pain scores, morphine consumption, associated side-effects were assessed for 48 hr postoperatively. In addition, patient's acceptance and satisfaction of the postoperative analgesic technique were also recorded.", 'During the first 24 hr, pain scores (3.3 +/- 9.6 mm vs 22.8 +/- 27.1 at H+6, 3.3 +/- 8.3 mm vs 25 +/- 26.7 mm at H+12, 7 +/- 14.9 mm vs 21.9 +/- 29 mm at H+18) and morphine consumption (0.56 +/- 2.12 mg vs 9.42 +/- 10.13 mg) were lower in Group I than in Group II. Urinary retention was the more frequent side-effect occurring in 37% of cases in Group I vs 11.5% in Group II (P < 0.05). No major complication occurred. Despite better analgesia provided by the use of intrathecal morphine, there was no difference in the satisfaction scores between groups.'] Does intrathecal morphine provide better postoperative analgesia than psoas compartment block after primary hip arthroplasty?