Intravenous vs Oral Acetaminophen as a Component of Multimodal Analgesia After Total Hip Arthroplasty: A Randomized, Blinded Trial.

Background: Multimodal analgesia including acetaminophen is increasingly popular for analgesia after total hip arthroplasty (THA). Intravenous (IV) administration of acetaminophen has pharmacokinetic benefits, but unclear clinical advantages. The authors hypothesized that IV acetaminophen would reduce pain with activity, opioid usage, or opioid-related side effects, compared to oral acetaminophen.

Methods: In this double-blinded, randomized, controlled trial, 154 THA patients received either IV or oral acetaminophen as part of a comprehensive opioid-sparing multimodal analgesia strategy. Primary outcomes were pain with physical therapy on postoperative day (POD) 1, opioid side effects (POD 1), and cumulative opioid use.

Results: There was no difference in opioid side effects, pain scores, or opioid use between the groups.

Conclusion: Patients in both groups had low pain scores, minimal opioid side effects, and limited opioid usage (corresponding to 6 doses of tramadol 100 mg over 3 days). This highlights multimodal analgesia as an effective method of pain control for THA.