Table 3

GRADE summary of findings for total knee arthroplasty

ComplicationsAnticipated absolute effects* (95% CI)Relative effect
(95% CI)
Participants
(studies) (n)
Certainty of the evidence
(GRADE)
Risk with no PNBRisk with PNB
Mortality1 per 1000 1 per 1000
(1 to 1)
OR 1.07
(0.92 to 1.24)
932 102
(5 RCTs, 5 observational studies)
⨁⨁◯◯
low
Cardiac without MI23 per 1000 19 per 1000
(19 to 20)
OR 0.83
(0.79 to 0.86)
720 282
(7 RCTs, 4 observational studies)
⨁⨁⨁◯
moderate†
MI10 per 1000 6 per 1000
(2 to 18)
OR 0.57
(0.18 to 1.78)
1360
(7 RCTs, 1 observational study)
⨁⨁⨁◯
moderate†
Pulmonary12 per 1000 10 per 1000
(9 to 10)
OR 0.84
(0.79 to 0.89)
721 469
(16 RCTs, 5 observational studies)
⨁⨁⨁◯
moderate†
Respiratory failure41 per 1000 16 per 1000
(8 to 31)
OR 0.37
(0.18 to 0.75)
1246
(9 RCTs, 4 observational studies)
⨁⨁⨁⨁
high†
Pneumonia22 per 1000 26 per 1000
(11 to 60)
OR 1.15
(0.47 to 2.80)
705
(6 RCTs)
⨁⨁⨁◯
moderate†
Gastrointestinal4 per 1000 3 per 1000
(3 to 4)
OR 0.93
(0.83 to 1.04)
720 230
(7 RCTs, 2 observational studies)
⨁⨁⨁◯
moderate†
Renal15 per 1000 14 per 1000
(13 to 15)
OR 0.96
(0.91 to 1.02)
720 111
(3 RCTs, 3 observational studies)
⨁⨁◯◯
low
Renal failure26 per 1000 21 per 1000
(8 to 52)
OR 0.82
(0.32 to 2.04)
685
(3 RCTs, 2 observational studies)
⨁⨁⨁◯
moderate†
Cognitive dysfunction130 per 1000 72 per 1000
(48 to 107)
OR 0.52
(0.34 to 0.80)
1563
(8 RCTs, 4 observational studies)
⨁⨁⨁⨁
high
Delirium143 per 1000 69 per 1000
(36 to 128)
OR 0.44
(0.22 to 0.88)
899
(3 RCTs, 2 observational studies)
⨁⨁⨁⨁
high
Stroke1 per 1000 1 per 1000
(1 to 1)
OR 0.95
(0.76 to 1.18)
719 734
(3 RCTs, 1 observational study)
⨁⨁◯◯
low†
Surgical site infection10 per 1000 9 per 1000
(8 to 9)
OR 0.86
(0.80 to 0.91)
796 090
(18 RCTs, 7 observational studies)
⨁⨁◯◯
low
Any infection21 per 1000 16 per 1000
(16 to 17)
OR 0.77
(0.73 to 0.80)
789 622
(8 RCT, 3 observational studies)
⨁⨁◯◯
low
Sepsis5 per 1000 6 per 1000
(1 to 32)
OR 1.37
(0.27 to 7.05)
433
(2 RCTs, 1 observational study)
⨁⨁◯◯
low*‡
Thromboembolism11 per 1000 10 per 1000
(9 to 10)
OR 0.90
(0.84 to 0.96)
790 835
(17 RCTs, 6 observational studies)
⨁⨁◯◯
low
Perioperative nerve injury6 per 1000 7 per 1000
(4 to 11)
OR 1.02 (0.59 to 1.76)8590
(1 observational study)
⨁⨁◯◯
low
Blood transfusion165 per 1000 152 per 1000
(151 to 154)
OR 0.91
(0.90 to 0.92)
1 250 014
(3 RCTs, 3 observational studies)
⨁⨁⨁◯
moderate†
Blood lossMD 42.53 lower
(52.08 lower to 32.98 lower)
890
(8 RCTs, 2 observational studies)
⨁⨁⨁⨁
high
Critical care admission67 per 1000 72 per 1000
(70 to 74)
OR 1.07
(1.04 to 1.10)
719 767
(2 RCTs, 2 observational studies)
⨁⨁◯◯
low
Readmission52 per 1000 35 per 1000
(32 to 37)
OR 0.66
(0.61 to 0.70)
146 453
(3 observational studies)
⨁⨁◯◯
low
Length of stayMD 0.02 higher
(0.01 lower to 0.04 higher)
86 770
(37 RCTs, 21 observational studies)
⨁⨁◯◯
low†‡
  • GRADE Working Group grades of evidence.

  • High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.

  • Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.

  • Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.

  • Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

  • *The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

  • † Optimal Information Size (OIS) low.

  • ‡Heterogeneity detected.

  • GRADE, Grading of Recommendations Assessment, Development, and Evaluation; MD, mean difference; MI, myocardial infarction; PNB, peripheral nerve block; RCT, randomized controlled trial.