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Journal of Anesthesia (2018) 32:341–350
https://doi.org/10.1007/s00540-018-2480-1
ORIGINAL ARTICLE
The role of sciatic nerve block to complement femoral nerve block
in total knee arthroplasty: a meta‑analysis of randomized controlled
trials
Andres Zorrilla‑Vaca
1,2
· Jinlei Li
1,2,3
Received: 1 March 2016 / Accepted: 4 March 2018 / Published online: 8 March 2018
© Japanese Society of Anesthesiologists 2018
Abstract
Introduction Femoral nerve block (FNB) appears to have higher postoperative analgesic benefits compared with the patient-
controlled analgesia (PCA) in total knee arthroplasty (TKA). However, the role of sciatic nerve block (SNB) as a complement
to FNB remains controversial. We performed a meta-analysis assessing the benefits of the SNB as a complement to FNB,
as well as comparing the efficacy of single-injection versus continuous SNB in TKA.
Methods Our group conducted a systematic literature search in PubMed, EMBASE and Google Scholar. We retrieved
randomized trials comparing either SNB versus placebo or continuous versus single-injection SNB. The intervention group
was the use of SNB as a complement to FNB, while the control group was FNB alone. Pain score at rest and movement (at
4, 12, 24, 48 and 72 h), patient-controlled intravenous opioid consumption, length of hospital stay, and incidence of nausea
were extracted from each study. Random-effects model was used for meta-analysis and standardized mean difference (SMD)
was used as the effect size.
Results Ten articles comprising 514 patients were included to compare the effects of SNB combined with FNB versus
FNB alone. Interventional group was found to significantly reduce pain score at for 4 h (SMD = − 0.94, 95% CI − 1.42 to
− 0.47, P < 0.001, I
2
= 76.5%) compared with the control group. Pain score at rest was significantly reduced at movement
for 12 h (SMD = − 0.29, 95% CI − 0.54 to − 0.04, P = 0.02, I
2
= 0%). Opioid consumption was significantly reduced at 24
(SMD = − 0.60, 95% CI − 1.01 to − 0.17, P = 0.01, I
2
= 69.1%) and 48 h (SMD = − 1.04, 95% CI − 1.46 to − 0.61, P < 0.001,
I
2
= 43.4%) after TKA using SNB as a complement to FNB. Three articles were additionally meta-analyzed to compare the
efficacy of single-injection (n = 79) versus continuous SNB (n = 79), being the latter one significantly associated with less
pain score at 24 (SMD = -0.77, 95% CI − 1.10 to − 0.45, P < 0.001, I
2
= 0%) and 48 h (SMD = − 0.69, 95% CI − 1.01 to
− 0.36, P < 0.001, I
2
= 0%), but not at 12 h (SMD = − 0.34, 95% CI − 0.73 to − 0.06, P = 0.10, I
2
= 0%).
Conclusions This meta-analysis provides evidence-based supports to the benefits of SNB as a complement to FNB in TKA.
The combination sciatic–femoral nerve block appears to be the optimal choice for patients in high risk of postoperative
opioids consumption or acute pain after TKA.
Keywords Sciatic nerve block · Patient safety · Femoral nerve block · Peripheral nerve block · Regional anesthesia
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s0054 0-018-2480-1) contains
supplementary material, which is available to authorized users.
* Andres Zorrilla-Vaca
andres.zorrilla@correounivalle.edu.co
Jinlei Li
jinlei.li@yale.edu
1
Department of Anesthesiology and Critical Care Medicine,
Johns Hopkins University School of Medicine, 600 N Wolfe
Street, Phipps 455, Baltimore, MD, USA
2
Present Address: Faculty of Health, Universidad del Valle
School of Medicine, Cali, Colombia
3
Department of Anesthesiology, Yale University, Yale New
Haven Hospital, New Haven, CT, USA
@Phil_Robichaud
@deepthiw
@JoseServera