BACKGROUND AND PURPOSE: To our knowledge, there is no evidence to support the use of local infiltration analgesia (LIA) for postoperative pain relief after periacetabular osteotomy (PAO). We investigated the effect of wound infiltration with a long-acting local anesthetic (ropivacaine) for postoperative analgesia after PAO. PATIENTS AND METHODS: We performed a randomized, double-blind, placebo-controlled trial (ClinicalTrials.gov: NCT00815503) in 53 patients undergoing PAO to evaluate the effect of local anesthetic infiltration on postoperative pain and on postoperative opioid consumption. All subjects received intraoperative infiltration followed by 5 postoperative injections in 10-hour intervals through a multi-holed catheter placed at the surgical site. 26 patients received ropivacaine and 27 received saline. The intervention period was 2 days and the observational period was 4 days. All subjects received patient-controlled opioid analgesia without any restrictions on the total daily dose. Pain was assessed at specific postoperative time points and the daily opioid usage was registered. RESULTS: Infiltration with 75 mL (150 mg) of ropivacaine did not reduce postoperative pain or opioid requirements during the first 4 days. INTERPRETATION: The clinical importance of ropivacaine as single component in postoperative treatment of pain is questionable, and we are planning further studies to explore the potential of LIA in larger volume-and also a multimodal regimen-to treat pain in this category of patients.