The Journal of Arthroplasty xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
A Comparison of Single-Shot Adductor Canal Block vs Femoral Nerve Catheter for Total Knee Arthroplasty We thank the author of the letter to the editor for his or her question and the opportunity to clarify points from our work. With regard to patient selection, baseline characteristics including age, gender, body mass index, American Society of Anesthesiologists (ASA) physical score, anesthesia type, and initial pain score were similar between groups using statistical significance at P values less than .05. Although we used chronologically continuous total knee arthroplasty (TKA) surgical candidates to relieve potential selection bias between comparison groups, ASA physical score for the femoral nerve catheter group did contain more patients with severe systemic disease leading to a higher portion of ASA III compared to the adductor canal block group, which contained more ASA II. Although this did not reach significance (P = .06), we recognize that this may contribute to selection bias and affect outcomes. This type of limitation, with lack of complete standardization, is a function of performing a retrospective study with a small sample size and is recognized within our discussion. The purpose of both continuous femoral nerve catheters and singleshot adductor canal blocks share the equivalent goal in providing postoperative analgesia for those undergoing TKA. However, we agree that the blocks are different anatomically and in duration with catheters theoretically providing prolonged pain control. Ultimately, the premise behind using the adductor canal instead of the femoral nerve canal is to avoid placing anesthetic near motor innervation to the sartorius and quadriceps femoris muscles to improve postoperative ambulation as meeting physical therapy requirements is one of the primary determinants in hospital discharge after TKA. The adductor canal contains branches of the saphenous and obturator nerves that are primarily sensory in nature making it an enticing location to provide analgesia. We were surprised that the single-shot adductor canal block provided similar pain relief, measured via self-reported pain scores and opioid consumption, given that it was not a continuous infusion of bupivacaine. We do recognize that having several different residents, fellows, and
faculty anesthesiologists placing the blocks throughout study duration may influence outcomes. Still, this may simply be due to adductor canal injections being easier to perform by anesthetic providers than femoral nerve catheters (FNCs), leading to more optimal bolus placement. We hope that institutions will continue to refine adductor canal blocks both in comparison to femoral nerve catheters and with regard to determining volumes and concentrations of single-injection bupivacaine that will optimize postoperative outcomes without sacrificing pain relief within multimodal analgesic protocols. Jordan L. Ludwigson BS ⁎ Samuel D. Tillmans BS University of Wisconsin School of Medicine and Public Health Madison, Wisconsin ⁎Reprint requests: Jordan L. Ludwigson, BS, University of Wisconsin School of Medicine and Public Health, W1694 County Road S Alma, WI 54610 Richard E. Galgon MD Tamara A. Chambers RN, MSN Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin John P. Heiner MD Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin Kristopher M. Schroeder MD Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin Available online xxxx
http://dx.doi.org/10.1016/j.arth.2015.09.017 0883-5403/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Ludwigson JL, et al, A Comparison of Single-Shot Adductor Canal Block vs Femoral Nerve Catheter for Total Knee Arthroplasty, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.09.017
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
A Comparison of Single-Shot Adductor Canal Block vs Femoral Nerve Catheter for Total Knee Arthroplasty We thank the author of the letter to the editor for his or her question and the opportunity to clarify points from our work. With regard to patient selection, baseline characteristics including age, gender, body mass index, American Society of Anesthesiologists (ASA) physical score, anesthesia type, and initial pain score were similar between groups using statistical significance at P values less than .05. Although we used chronologically continuous total knee arthroplasty (TKA) surgical candidates to relieve potential selection bias between comparison groups, ASA physical score for the femoral nerve catheter group did contain more patients with severe systemic disease leading to a higher portion of ASA III compared to the adductor canal block group, which contained more ASA II. Although this did not reach significance (P = .06), we recognize that this may contribute to selection bias and affect outcomes. This type of limitation, with lack of complete standardization, is a function of performing a retrospective study with a small sample size and is recognized within our discussion. The purpose of both continuous femoral nerve catheters and singleshot adductor canal blocks share the equivalent goal in providing postoperative analgesia for those undergoing TKA. However, we agree that the blocks are different anatomically and in duration with catheters theoretically providing prolonged pain control. Ultimately, the premise behind using the adductor canal instead of the femoral nerve canal is to avoid placing anesthetic near motor innervation to the sartorius and quadriceps femoris muscles to improve postoperative ambulation as meeting physical therapy requirements is one of the primary determinants in hospital discharge after TKA. The adductor canal contains branches of the saphenous and obturator nerves that are primarily sensory in nature making it an enticing location to provide analgesia. We were surprised that the single-shot adductor canal block provided similar pain relief, measured via self-reported pain scores and opioid consumption, given that it was not a continuous infusion of bupivacaine. We do recognize that having several different residents, fellows, and
faculty anesthesiologists placing the blocks throughout study duration may influence outcomes. Still, this may simply be due to adductor canal injections being easier to perform by anesthetic providers than femoral nerve catheters (FNCs), leading to more optimal bolus placement. We hope that institutions will continue to refine adductor canal blocks both in comparison to femoral nerve catheters and with regard to determining volumes and concentrations of single-injection bupivacaine that will optimize postoperative outcomes without sacrificing pain relief within multimodal analgesic protocols. Jordan L. Ludwigson BS ⁎ Samuel D. Tillmans BS University of Wisconsin School of Medicine and Public Health Madison, Wisconsin ⁎Reprint requests: Jordan L. Ludwigson, BS, University of Wisconsin School of Medicine and Public Health, W1694 County Road S Alma, WI 54610 Richard E. Galgon MD Tamara A. Chambers RN, MSN Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin John P. Heiner MD Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin Kristopher M. Schroeder MD Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin Available online xxxx
http://dx.doi.org/10.1016/j.arth.2015.09.017 0883-5403/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Ludwigson JL, et al, A Comparison of Single-Shot Adductor Canal Block vs Femoral Nerve Catheter for Total Knee Arthroplasty, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.09.017
