Geoffrey Westrich, MDDirector of ResearchAdult Reconstruction and Joint Replacement ServiceHospital for Special SurgeryNYC

Hip Replacement Surgery Pain: No Benefit To IV Acetaminophen over Pills Interview with:

Geoffrey Westrich, MDDirector of ResearchAdult Reconstruction and Joint Replacement ServiceHospital for Special SurgeryNYC

Dr. Westrich

Geoffrey Westrich, MD
Director of Research
Adult Reconstruction and Joint Replacement Service
Hospital for Special Surgery
NYC What is the background for this study?

Response: Recent mortality trends in the U.S. associated with opioid use disorders have brought to the forefront of national debate the desirability of minimizing the use of potentially addictive pain management therapies.  Pain management after hip replacement surgery is an important part of patient care, and  opioids are frequently given as a major part of postoperative pain management.

At the same time, multimodal analgesia, the administration of anesthetic agents and medications agents targeting multiple pain pathways, has seen increased popularity in pain management after hip replacement surgery.  At Hospital for Special Surgery (HSS), the multimodal protocol entails the use of several different anesthetic agents and medications both during and after surgery to control pain, minimize the use of opioids and reduce side effects.

The use of non-opioid analgesics such as acetaminophen allows for a reduction in opioid administration after surgery [1]. Acetaminophen, commonly known as Tylenol, has traditionally been administered orally, but more recently an intravenous (IV) preparation has become available.  IV acetaminophen after major orthopedic surgery was shown to provide effective analgesia and reduce morphine administration by 33%, compared to placebo [2].

Unless a patient is unable to take acetaminophen, it is commonly used as part of the multimodal protocol due to its efficacy and minimal contraindications. Although intravenous (IV) acetaminophen presents pharmacokinetic benefits, such as increasing both serum blood and cerebrospinal fluid levels more rapidly, there is limited analysis of its potential clinical advantages compared to oral acetaminophen.  We hypothesized that there could be a reduction in pain with activity, opioid usage, or opioid- related side effects among patients receiving IV acetaminophen compared to oral acetaminophen following hip replacement surgery What are the main findings?

Response: All 154 patients in the study had hip replacement surgery at HSS. They all received the standard multifaceted pain control protocol after surgery and were randomly assigned to one of two groups. One group received intravenous acetaminophen, while the other group was given the oral pill form. It was a double blinded study, which meant that neither the patients nor their doctors knew which individuals were receiving intravenous versus oral acetaminophen. Those getting IV acetaminophen also received a placebo in pill form, and those given oral acetaminophen received a placebo IV solution.

The study found that there was no benefit to using the more costly and more invasive intravenous form of acetaminophen. Both groups in the study had low pain scores with activity, minimal opioid-related side effects, limited opioid usage after hip replacement surgery, and most important, high patient satisfaction scores (9/10 in both groups). What should readers take away from your report?

Response: The study highlights our specific Hospital for Special Surgery multimodal analgesia protocol as an effective method of pain control for patients having hip replacement surgery, with very high patient satisfaction (rated 9/10). Regarding oral versus intravenous acetaminophen, the study supports the routine use of the oral form, which is less costly and less invasive to administer, if our specific protocol is followed.  Other institutions that follow different protocols may see a benefit from the intravenous form of acetaminophen. What recommendations do you have for future research as a result of this work? 

Response: Every patient is different, and how to optimize multimodal therapy for a given patient is an important field of research.  At HSS, research is ongoing in the area of pain management, including both randomized trials of various other pain medications and also other pain management protocols.  Clearly, our ability to reduce pain following surgery is of paramount importance and we will continue to focus our efforts to achieve these goals. 


  1. Remy C, Marret E, Bonnet F. Effects of acetaminophen on morphine side-effects and consumption after major surgery: meta-analysis of randomized controlled trials. British journal of anaesthesia 94(4): 505, 2005
  2. Sinatra RS, Jahr JS, Reynolds LW, Viscusi ER, Groudine SB, Payen-Champenois C. Efficacy and safety of single and repeated administration of 1 gram intravenous acetaminophen injection (paracetamol) for pain management after major orthopedic surgery. Anesthesiology 102(4): 822, 2005

Citation: AAOS 19 abstract

Oral Acetaminophen as a Component of Multimodal Analgesia After Total Hip Arthroplasty: A Randomized, Double Blinded, Controlled Trial

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Mar 19, 2019 @ 11:33 pm

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