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    To Block or Not to Block…

    Fred D. Cushner, MD, from Northwell Health Orthopedic Institute in New York, New York, was initially a fan of peripheral nerve blocks for his total knee arthroplasty (TKA) patients.

    “But as it turned out, blocks aren’t so good,” he said during a presentation at a symposium last year.

    Issues arose soon after implementing a multimodal pain management protocol in his practice that included peripheral nerve blocks:

    • Operating room time. The time it took for the anesthesiologist to place the nerve block would throw off the operating roolm (OR) schedule, especially when Dr. Cushner was utilizing 2 ORs or when he was performing bilateral TKA.
    • Delayed recovery of motor function. Dr. Cushner was concerned that his patients were at risk of falls and required a knee immobilizer until the peripheral nerve block wore off. In addition, physical therapy was often delayed as much as a day due to impaired motor function.
    • Learning curve. Some of the anesthesiologists were still learning how to place the nerve blocks, and as a result, some blocks would be incomplete or fail to provide pain relief.

    Because of these issues, Dr. Cushner began looking at alternatives to nerve blocks, keeping in mind his goals for perioperative pain management in his TKA patients:

    • Keep the patients happy by minimizing pain
    • Prevent pain before it starts
    • Eliminate parenteral opioids if possible
    • Accomplish all of the above without side effects

    Periarticular injection of anesthetic/analgesic agents is one such option. The question Dr. Cushner had was whether periarticular injections would be effective without causing problems.

    A study by Ranawat et al [1] showed good results with periarticular injections, but the authors concluded that “unfortunately we have still not achieved the ideal technique.”

    Technique

    And technique is essential for the effectiveness of periarticular injections. Dr. Cushner has found that the key points for injection technique include the following:

    • Use a small-gauge needle
    • Use multiple small-volume injections
    • Follow the 20/10/20 rule: 20 mL of solution in the posterior capsule; 10 mL in the periosteum and fat pad; and 20 mL in the subcutaneous tissues, favoring the medial side

    The goal is to concentrate these injections where the nerves are, Dr. Cushner said, and as a “rule of thumb,” nerves go where the blood vessels go. A 2015 study by Guild et al [2] identified 6 regions of the knee with increased neurosensory perception that should be targeted with periarticular injections:

    • Suprapatellar pouch/quadriceps tendon
    • Medial retinaculum
    • Patella tendon and fat pad
    • Medial collateral ligament/medial meniscus/medial capsule
    • Both cruciate ligaments
    • Lateral collateral ligament/lateral meniscus/lateral capsule

    Dr. Cushner recommends getting into a routine in which the periarticular injections are done the same way and at the same stage of the procedure. His preference is to do the injections after he has completed the trial step.

    Results

    How do periarticular injections compare with femoral/sciatic nerve blocks in TKA patient? A study by Spangehl et al [3] found similar pain scores between the periarticular injection and nerve block groups. The periarticular group had a shorter length of stay and fewer nerve symptoms, and they used only slightly more opioids on the day of surgery.

    Dr. Cushner also shared his initial findings comparing nerve blocks and periarticular injections in patients undergoing bilateral TKA. The study included 14 patients who had the nerve block on 1 knee and periarticular injection on the other. Only 4 patients preferred the femoral/sciatic block; the other 10 preferred the periarticular side or had no preference. No rebound pain was found in any of the patients.

    Solution Injected

    Dr. Cushner’s preferred periarticular injection cocktail contains 20 mL of liposomal bupivacaine (EXPAREL) and 30 mL of 0.25% bupivacaine and epinephrine (Marcaine), for a total of 50 mL of injectable. The 0.25% bupivacaine and epinephrine provides more-immediate pain relief, while the liposomal bupivacaine provides longer-duration pain control, he said.

    This cocktail can be expanded using 0.9% normal saline if more volume is desired.

    Dr. Cushner prefers 0.25% bupivacaine and epinephrine because with this concentration, the drug amount remains well below toxic levels, even when used in bilateral TKA.

    A study by Surdam et al [4] compared liposomal bupivacaine with femoral nerve block and found that the nerve block group had greater flexion, but the liposomal bupivacaine group had improved ambulation and decreased length of stay.

    The pain scores for the liposomal bupivacaine group were higher than nerve block group on POD0 but lower than the nerve block group on POD1 through POD3. [4] Dr. Cushner noted that no “Marcaine bridge” was used in the periarticular injection group, which he believes may be the reason for the higher pain scores on POD0.

    Dr. Cushner said that studies comparing liposomal bupivacaine to other cocktails containing ropivacaine or plain bupivacaine have been inconclusive.

    Click the image above to watch Dr. Cushner’s presentation.

    References

    1. Maheshwari AV, Blum YC, Shekhar L. et al. Multimodal pain management after total hip and knee arthroplasty at the Ranawat Orthopaedic Center. Clin Orthop Relat Res (2009) wol 467 no 6: p1418
    2. Guild GN 3rd, Galindo RP, Marino J, Cushner FD, Scuderi GR. Periarticular regional analgesia in total knee arthroplasty: a review of the neuroanatomy and injection technique. Orthop Clin North Am. 2015 Jan;46(1):1-8
    3. Spangehl MJ, Clarke HD, Hentz, JG et al. The Chitranjan Ranawat Award: Periarticular injections and femoral & sciatic blocks provide similar pain relief after TKA: a randomized clinical trial. Clin Orthop Relat Res (2015) vol 473 no 1 p45
    4. Surdam JW, Licini DJ, Baynes NT, Arce BR. The use of exparel (liposomal bupivacaine) to manage postoperative pain in unilateral total knee arthroplasty patients. J Arthroplasty. 2015 Feb;30(2):325-9. Epub 2014 Sep 16.