Effect of intravenous acetaminophen on postoperative outcomes in hip fracture patients: a systematic review and narrative synthesis.

PURPOSE: Hip fractures are debilitating in older adults because of their impact on quality of life. Opioids are associated with adverse effects in this population, so oral acetaminophen is commonly prescribed to minimize opioid use. Intravenous (iv) acetaminophen has been reported to have superior efficacy and bioavailability than oral acetaminophen. Nevertheless, its effect on postoperative outcomes in emergency hip fractures is unclear. This systematic review assessed the effect of iv acetaminophen on postoperative outcomes in older hip fracture patients.

SOURCE: We searched multiple databases from inception to June 2021 for studies on adults > 50 yr of age undergoing emergency hip fracture surgery who received iv acetaminophen (or paracetamol) and that reported postoperative outcomes. Relevant titles, abstracts, and full texts were screened based on the eligibility criteria. The Newcastle-Ottawa scale was used to assess the quality of the selected papers.

PRINCIPAL FINDINGS: Of 3,510 initial studies, four met the inclusion criteria. One was a prospective cohort study and three were retrospective cohort studies. All four studies used historical control groups. Three studies reported a significantly lower mean opioid dose with iv acetaminophen than with oral acetaminophen. Three studies also reported a significantly shorter hospital stay. One study each reported a significant decrease in the number of missed physical therapy sessions, the need for one-to-one supervision, and episodes of delirium.

CONCLUSION: There is very limited low-level evidence that iv acetaminophen improves preoperative and postoperative analgesia and shortens hospital stay in older hip fracture patients. Nevertheless, our results should be interpreted with caution since there are no prospective randomized trials investigating whether iv acetaminophen improves postoperative outcomes in this patient population.

STUDY REGISTRATION: PROSPERO (CRD42021198174); registered 15 August 2021.