Intra-articular magnesium to alleviate postoperative pain after arthroscopic knee surgery: a meta-analysis of randomized controlled trials

Table 2 The GRADE evidence quality for each outcome

Outcome	Number of Included Studies	Total Participants (Mg/ Control)	MD (95% CI)	Heterogeneity	Quality of Evidence (GRADE)
VAS at rest
at 2h	8	212/211	-0.74 (-0.84, -0.64)	I² = 0%, P = 0.51	LOW
at 4h	6	152/151	-0.24 (-0.37, -0.11)	I² = 45%, P = 0.11	MODERATE ^d
at 12h	6	152/152	-0.53 (-0.64, -0.41)	I² = 47%, P = 0.10	HIGH
at 24h	7	186/186	-0.33 (-0.42, -0.24)	I² = 30%, P = 0.20	HIGH
VAS with movement
at 2h	7	140/139	-0.46 (-0.64, -0.27)	I² = 39%, P = 0.14	HIGH
at 4h	6	150/149	-0.85 (-1.40, -0.30)	I² = 95%, P <0.00001	MODERATE ^b
at 12h	6	150/149	-0.83 (-1.17, -0.48)	I² = 71%, P = 0.004	MODERATE ^c
at 24h	7	170/169	-0.58 (-0.79, -0.36)	I² = 45%, P = 0.09	HIGH
Anesthetic Consumption	8	229/220	-4.23 (-4.64, -3.82)	I² = 27%, P = 0.21	HIGH
Anesthetic duration	11	311/302	329.99 (228.73, 431.24)	I² = 99%, P<0.00001	LOW ^b

(1) GRADE working group grades of evidence:
High quality: Further research is very unlikely to change our confidence in the estimate of effect
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate
Very low quality: Any estimate of effect is very uncertain
(2) Explanations:
^aStudy limitation: included trials are quasi design
^bInconsistency of results: large heterogeneity
^cIndirectness of evidence: large differences between the interventions in different trials
^dImprecision: small sample size and wide 95%CI
^eReporting bias: positive values showing benefits of the studied intervention

ISSN: 1749-799X