The findings of a study indicated that intravenous acetaminophen is not superior to oral acetaminophen in patients undergoing total knee arthroplasty in terms of pain scores at 24 hours, 48 hours, and total morphine intake at 24 hours. However, intravenous acetaminophen can considerably lower the length of hospital stay.

A systematic review and meta-analysis were carried out to examine the efficacy and safety of intravenous versus oral acetaminophen on pain and recovery after knee surgery. Pubmed, Cochrane Library, and Embase databases were extensively searched to find the relevant randomized trials and cohort studies. Five studies that compared intravenous acetaminophen groups with oral acetaminophen groups were incorporated in the meta-analysis.

To assure the reliability and authenticity of results, the findings were reported based on the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. The pooled outcomes demonstrated no vital differences between the intravenous acetaminophen groups and oral acetaminophen cohorts in terms of visual analog scale score at 24 hours, 48 hours, and total morphine intake at 24 hours. However, a vital difference in the patient's length of hospital stay was witnessed.

Thus, both intravenous and oral acetaminophen appears to yield comparable pain alleviation in patients undergoing total knee arthroplasty.