Efficacy of intravenous acetaminophen in multimodal management for pain relief following total knee arthroplasty: a meta-analysis

Table 3 Subgroup analysis of the total morphine consumption

Subgroups	No. of studies	Mean difference [95% CI]	P value	I² (%)	Between subgroup significance
Total morphine consumption
Allocation concealment
Adequate	2	− 2.39 (− 43.70, 38.92)	0.910	94.5	0.002
Unclear	2	− 18.62 (− 23.56, − 0.08)	0.000	0	0.002
Study type
RCT	1	− 19.70 (− 22.35, − 15.43)	0.029	0	0.124
RCS	3	− 20.45 (− 24.04, − 16.85)	0.038	0	0.124
Acetaminophen dose
1000 mg/day	3	− 4.42 (− 33.04, 24.20)	0.762	89.4	0.139
4000 mg/day	1	− 19.00 (− 24.03, − 13.97)	0.000		0.139
Anesthesia
GA	2	− 2.39 (− 43.70, 38.92)	0.910	94.5	0.048
SA	2	− 18.62 (− 23.56, − 13.68)	0.000		0.048

GA general anesthesia, SA spinal anesthesia, RCT randomized controlled trials, RCS retrospective controlled studies

ISSN: 1749-799X