Infiltration Between the Popliteal Artery and Capsule of the Knee (iPACK): Essential Anatomy, Technique, and Literature Review
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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 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.
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.
KeywordsInfiltration of the interspace between the popliteal artery and the capsule of the knee iPACK Posterior knee anatomy Posterior knee analgesia Total knee arthroplasty analgesia
Compliance with Ethical Standards
Conflict of Interest
Sanjay K. Sinha has received compensation from Pacira Pharmaceuticals for contributing to speaker’s bureaus and from Flexion Therapeutics for service as a consultant.
Alexa Clement declares that she has no conflict of interest.
Ann-Marie Surette declares that she has no conflict of interest.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
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