Comparison 4. Subgroup analyses by co‐analgesic agents.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Pain at rest: day 1 (10‐point numerical rating scale or equivalent)	5	511	Mean Difference (IV, Random, 95% CI)	‐0.59 [‐1.12, ‐0.07]
1.1 None	1	70	Mean Difference (IV, Random, 95% CI)	‐0.25 [‐1.65, 1.15]
1.2 At least one agent	4	441	Mean Difference (IV, Random, 95% CI)	‐0.65 [‐1.27, ‐0.03]
2 Pain on movement: day 1 (10‐point numerical rating scale or equivalent)	3	407	Mean Difference (IV, Random, 95% CI)	‐1.13 [‐2.26, ‐0.01]
2.1 None	0	0	Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
2.2 At least one agent	3	407	Mean Difference (IV, Random, 95% CI)	‐1.13 [‐2.26, ‐0.01]
3 Opioid consumption via patient‐controlled analgesia: day 1 (mg morphine equivalent)	6	528	Mean Difference (IV, Random, 95% CI)	‐11.98 [‐19.80, ‐4.17]
3.1 None	1	70	Mean Difference (IV, Random, 95% CI)	‐45.70 [‐82.74, ‐8.66]
3.2 At least one agent	5	458	Mean Difference (IV, Random, 95% CI)	‐10.34 [‐17.23, ‐3.45]