Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Clinical Trial
. 2021 Jan 13:14:53-59.
doi: 10.2147/JPR.S282286. eCollection 2021.

Minimum Effective Analgesic Concentration of Ropivacaine in Saphenous Block Guided by Ultrasound for Knee Arthroscopic Meniscectomy: Randomized, Double-Blind Study

Ed Carlos Rey Moura  1 , Caio Marcio Barros de Oliveira  2 , Plinio da Cunha Leal  2 , Rioko Kimiko Sakata  1
Affiliations
Clinical Trial

Minimum Effective Analgesic Concentration of Ropivacaine in Saphenous Block Guided by Ultrasound for Knee Arthroscopic Meniscectomy: Randomized, Double-Blind Study

Ed Carlos Rey Moura et al. J Pain Res. .

Abstract

Background: After knee surgery, analgesia should be effective for mobilization and discharge.

Aim of the study: The primary objective of this study was to achieve the lowest effective analgesic concentration (MEC50 and MEC90) of ropivacaine for saphenous nerve block in arthroscopic meniscectomy. The secondary objective was to determine whether the block causes muscle weakness in the postoperative period.

Methods: The study was randomized, comparative, and double-blind. Fifty-one patients between 18 and 65 years old of both sexes, ASA I or II, who underwent knee arthroscopic meniscectomy at São Domingos Hospital were included. Patients underwent saphenous nerve block with 10 mL of ropivacaine administered by using the up-and-down method. The ropivacaine concentration was determined based on the previous patient's response (a biased-coin up-down design sequential method). If a patient had a negative response, the concentration of ropivacaine was increased by 0.05% in the next patient; if the response was positive, the next patient was randomized to be administered the same concentration of ropivacaine or a 0.05% lower concentration. Successful block was defined as pain <4 during 6 h. Patients underwent general anesthesia with 30 µg/kg alfentanil and propofol and maintenance with propofol, and, if necessary, remifentanil was administered. Postoperative analgesia was complemented with dipyrone, and if necessary, tramadol (100 mg) could be used. The following parameters were assessed: the success of the block; pain intensity after 2, 4, and 6 h; the consumption of remifentanil; time to the first analgesic supplementation; percent of patients who needed analgesics during 6h; and muscle strength.

Results: The MEC50 of ropivacaine was 0.36%, and the MEC90 was 0.477%. The block was successful in 45 patients.

Conclusion: Saphenous block with 10 mL of 0.36% ropivacaine provides adequate analgesia for outpatient meniscectomy.

Keywords: MEC50; MEC90; block; meniscectomy; saphenous nerve; up-and-down.

PubMed Disclaimer

Conflict of interest statement

The authors report no conflicts of interest in this work.

Figures

Figure 1
Figure 1
CONSORT flowchart. There were assessed for eligibility 51 participants, and no one was excluded. All of them were randomized and submitted to block, with blocking failure in 6 participants. All participants completed the study.
Figure 2
Figure 2
Ropivacaine concentration and successful or failure of the saphenous block for up-and-down sequence of patients.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Byrne K, Smith C. Preemptive analgesia: an unobtainable goal? J Cardiothorac Vasc Anesth. 2019;33(2):460–461. doi:10.1053/j.jvca.2018.08.008 - DOI - PubMed
    1. Barreveld A, Witte J, Chahal H, Durieux ME, Strichartz G. Preventive analgesia by local anesthetics: the reduction of postoperative pain by peripheral nerve blocks and intravenous drugs. Anesth Analg. 2013;116(5):1141–1161. doi:10.1213/ANE.0b013e318277a270 - DOI - PMC - PubMed
    1. Rahimzadeh P, Faiz HR, Imani F, Hobika GG, Abbasi A, Nader ND. Relieving pain after arthroscopic knee surgery: ultrasound-guided femoral nerve block or adductor canal block? Turk Anest Rean Dern Derg. 2017;45(4):218–224. doi:10.5152/TJAR.2017.00868 - DOI - PMC - PubMed
    1. Tantry TP, Muralishankar BG, Rajesh H. Use of a single injection femoral nerve block in the patients of total knee replacement with concomitant epidural analgesia. J Clin Diagn Res. 2012;6(10):1744–1748. doi:10.7860/JCDR/2012/4920.2620 - DOI - PMC - PubMed
    1. Yao J, Zeng Z, Jiao Z, Wang A, Wang J, Yu A. Optimal effective concentration of ropivacaine for postoperative analgesia by single-shot femoral -sciatic nerve block in outpatient knee arthroscopy. J Intern Med Res. 2013;41(2):395–403. doi:10.1177/0300060513476427 - DOI - PubMed