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Current Anesthesiology Reports

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01-12-2019 | Nerve Block | Regional Anesthesia (P Kukreja, Section Editor)

Infiltration Between the Popliteal Artery and Capsule of the Knee (iPACK): Essential Anatomy, Technique, and Literature Review

Authors: Sanjay K. Sinha, Alexa Clement, Ann-Marie Surette

Published in: Current Anesthesiology Reports | Issue 4/2019

Abstract

Purpose of Review

In this review, we discuss the essential iPACK (Infiltration between the Popliteal Artery and Capsule of the Knee) anatomy, block technique as well as potential complications, contraindications, and relevant literature evaluating the efficacy of the iPACK block.

Recent Findings

Recent literature supports the efficacy of the iPACK in controlling pain, improving postoperative physical therapy performance, and decreasing hospital length of stay (LOS). Cadaver studies have demonstrated that injection of dye in the tissue plane between the popliteal artery and the femoral shaft cranial to femoral condyles spreads to the genicular nerves that innervate the posterior knee and forms the basis of the analgesic mechanism of the iPACK. Randomized controlled trials have shown that the iPACK, when used in combination with a femoral nerve block (FNB) or adductor canal block (ACB), is superior to a FNB or ACB alone in controlling postoperative pain.

Summary

The iPACK controls posterior knee pain following total knee arthroplasty (TKA) by anesthetizing the articular branches from the sciatic and obturator nerves. This is a safe and relatively simple block to perform with a low risk of serious complications.

Sinha S, Abrams J, Sivasenthil S, Freitas D, D’Allesio J, Barnett J, Weller R, Lewis C. Use of ultrasound guided popliteal fossa infiltration to control pain after total knee arthroplasty: a prospective, randomized, observer-blinded study [Abstract P 52]. Presented at: American Society of Regional Anesthesia Meeting; March 15-18 2012; San Diego, CA.

•• Terkawi AS, Mavridis D, Sessler DI, Nunemaker MS, Doais KS, Terkawi RS, et al. Pain management modalities after total knee arthroplasty: a network meta-analysis of 170 randomized controlled trials. Anesthesiology. 2017;126(5):923–37 Meta-analysis of analgesic techniques for TKA where the authors compared the efficacy of various peripheral nerve blocks and epidural analgesia, analyzing differences in pain scores, opioid consumption, and range of motion. CrossRef

Kukreja P, Feinstein J, Kalagara HK, Huntley SR, Lee SR, Naranje S, et al. A summary of the anatomy and current regional anesthesia practices for postoperative pain management in total knee arthroplasty. Cureus. 2018;10(6):e2755. https://doi.org/10.7759/cureus.2755.CrossRefPubMedPubMedCentral

• Runge C, Moriggl B, Borglum J, Bendtsen TF. The spread of ultrasound-guided injectate from the adductor canal to the genicular branch of the posterior obturator nerve and the popliteal plexus: a cadaveric study. Reg Anesth Pain Med. 2017;42:725–30. https://doi.org/10.1097/AAP.0000000000000675A cadaveric study demonstrating the anatomic communication between the adductor canal and popliteal fossa. CrossRefPubMed

Horner G, Dellon AL. Innervation of the human knee joint and implications for surgery. Clin Orthop Relat Res. 1994;301:221–6.

Gardner E. The innervation of the knee joint. Anat Rec. 1948;101:109–30.CrossRef

• Burkett-St. Laurant D, Peng P, Giron Arango L, Niazi AU, Chan V, Agur A, et al. The nerve of the adductor canal and the innervation of the knee: an anatomic study. Reg Anesth Pain Med. 2016;41:321–7. https://doi.org/10.1097/AAP.0000000000000389A cadaveric study identifying the innervation of posteromedial knee. CrossRef

•• Sinha SK. How I do it: Infiltration between Popliteal Artery and Capsule of the Knee (iPACK). ASRA newsletter; February 2019. https://www.asra.com/asra-news/article/158/how-i-do-it-infiltration-between-popliteDescriptive review of the relevant iPACK anatomy and procedural technique by the inventor of the iPACK, Dr Sanjay Sinha

•• Niesen AD, Harris DJ, Johnson CS, Stoike DE, Smith HM, Jacob AK, et al. Interspace between Popliteal Artery and posterior Capsule of the Knee (IPACK) injectate spread: a cadaver study. J Ultrasound Med. 2018;00:1–5. https://doi.org/10.1002/jum.14761A cadaveric study examining the spread of colored latex during iPACK injections, suggesting a possible mechanism for the analgesic effect of this block. The potential for local anesthetic spread to the tibial and common peroneal nerves is also highlighted. CrossRef

10.

Frank H. Netter. Atlas of human anatomy. 3rd Edn. ICON Learning Systems 2003.

11.

•• Tran J, Giron AL, Peng P, Sinha SK, Agur A, Chan V. Evaluation of the iPACK block injectate spread: a cadaveric study. Reg Anesth Pain Med. 2019;44:689–94. https://doi.org/10.1136/rapm-2018-100355A cadaveric study examining the spread of methylene blue–colored water following distal and proximal iPACK injection techniques. This study describes the different articular branches that are most likely contributing to the analgesic effect of the iPACK block. CrossRef

12.

Thobhani S, Scalercio L, Elliott CE, Nossaman BD, Thomas LC, Yuratich D, et al. Novel regional techniques for total knee arthroplasty promote reduced hospital length of stay: an analysis of 106 patients. Ochsner J. 2017;17(3):233–8.PubMedPubMedCentral

13.

•• Sankineani SR, Reddy ARC, Eachempati KK, Jangale A, Gurava Reddy AV. Comparison of adductor canal block and IPACK block (interspace between the popliteal artery and the capsule of the posterior knee) with adductor canal block alone after total knee arthroplasty: a prospective control trial on pain and knee function in immediate postoperative period. Eur J Orthop Surg Traumatol. 2018;28(7):1391–5. https://doi.org/10.1007/s00590-018-2218-7This prospective study compares pain scores between two cohorts of patients undergoing unilateral TKA. The authors found significantly lower pain scores in the combination group of adductor canal block (ACB) + iPACK when compared with adductor canal block alone. CrossRefPubMed

14.

•• Kim DH, Beathe JC, Lin Y, YaDeau JT, Maalouf DB, Goytizolo E, et al. Addition of infiltration between the popliteal artery and the capsule of the posterior knee and adductor canal block to periarticular injection enhances postoperative pain control in total knee arthroplasty: a randomized controlled trial. Anesth Analg. 2018. https://doi.org/10.1213/ANE.0000000000003794This randomized controlled trial compares postoperative pain scores between patients receiving either periarticular injection alone or periarticular injection in combination with adductor canal block and iPACK injection. The authors found significantly lower pain scores and opioid consumption in the study group of periarticular injection + ACB + iPACK.

Title: Infiltration Between the Popliteal Artery and Capsule of the Knee (iPACK): Essential Anatomy, Technique, and Literature Review
Authors: Sanjay K. Sinha
Alexa Clement
Ann-Marie Surette
Publication date: 01-12-2019
Publisher: Springer US
Keyword: Nerve Block
Published in: Current Anesthesiology Reports / Issue 4/2019
Electronic ISSN: 2167-6275
DOI: https://doi.org/10.1007/s40140-019-00358-5

At a glance: The STEP trials

Springer Medicine

Infiltration Between the Popliteal Artery and Capsule of the Knee (iPACK): Essential Anatomy, Technique, and Literature Review

Abstract

Purpose of Review

Recent Findings

Summary

At a glance: The STEP trials

Springer Medicine

Abstract

Purpose of Review

Recent Findings

Summary

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