Background and ObjectivesThe precise location of the adductor canal remains controversial among anesthesiologists. In numerous studies of the analgesic effect of the so-called adductor canal block for total knee arthroplasty, the needle insertion point has been the midpoint of the thigh, determined as the midpoint between the anterior superior iliac spine and base of patella. “Adductor canal block” may be a misnomer for an approach that is actually an injection into the femoral triangle, a “femoral triangle block.” This block probably has a different analgesic effect compared with an injection into the adductor canal. We sought to determine the exact location of the adductor canal using ultrasound and relate it to the midpoint of the thigh.MethodsTwenty-two volunteers were examined using ultrasound. The proximal end of the adductor canal was identified where the medial border of the sartorius muscle intersects the medial border of the adductor longus muscle. The distal end of the adductor canal is the adductor hiatus, which was also visualized ultrasonographically.ResultsThe mean distance from the anterior superior iliac spine to the midpoint of the thigh was 22.9 cm (range, 20.3–24.9 cm). The mean distance from the anterior superior iliac spine to the proximal end of the adductor canal was 27.4 cm (range, 24.0–31.4 cm). Consequently, the mean distance from the midpoint of the thigh to the proximal end of the adductor canal was 4.6 cm (range, 2.3–7.0 cm).ConclusionsIn all volunteers, the midpoint of the thigh was proximal to the beginning of the adductor canal, suggesting that an injection performed at this level is in fact a femoral triangle block.

Background: A femoral nerve block relieves pain after total hip arthroplasty, but its use is controversial due to motor paralysis accompanied by an increased risk of fall.Assumedly, the iliopsoas plane block (IPB) targets the hip articular branches of the femoral nerve without motor blockade. However, this has only been indicated in a cadaver study. Therefore, we designed this volunteer study.Methods: Twenty healthy volunteers were randomly allocated to blinded paired active vs. sham IPB (5 mL lidocaine 18 mg/mL with epinephrine vs saline). The primary outcome was reduction of maximal force of knee extension after IPB compared to baseline. Secondary outcomes included reduction of maximal force of hip adduction, and the pattern of injectate spread assessed with magnetic resonance imaging.Results: Mean (confidence interval) change of maximal force of knee extension from baseline to after IPB was −9.7 N (−22, 3.0) (P = .12) (n = 14). The injectate was consistently observed in an anatomically well-defined closed fascial compartment between the intra-and extra-pelvic components of the iliopsoas muscle anterior to the hip joint. Conclusion:We observed no significant reduction of maximal force of knee extension after an IPB. The injectate was contained in a fascial compartment previously shown to contain all sensory branches from the femoral nerve to the hip joint. The clinical consequence of selective anesthesia of all sensory femoral nerve branches from the hip could be a reduced risk of fall compared to a traditional femoral nerve block. Registration of Trial:The trial was prospectively registered in EudraCT (Reference:2018-000089-12, https ://www.clini caltr ialsr egist er.eu/ctr-searc h/searc h?query =2018-000089-12).

Perineural dexamethasone as an adjuvant for the single-injection subsartorial saphenous nerve block can prolong analgesia and reduce opioid-requiring pain after major ankle surgery.

Background and objectives For pain relief after total knee arthroplasty (TKA), an injection at the midthigh level may produce analgesia inferior to that of a femoral nerve block as the anterior femoral cutaneous nerves (intermediate femoral cutaneous nerve (IFCN) and medial femoral cutaneous nerve (MFCN)) are not anesthetized. The IFCN can be selectively anesthetized in the subcutaneous tissue above the sartorius muscle and the MFCN by an injection in the proximal part of the femoral triangle (FT). The primary aim was to investigate the area of cutaneous anesthesia in relation to the surgical incision for TKA and anteromedial knee area after intermediate femoral cutaneous nerve blockade (IFCNB) in combination with an injection in the proximal or distal part of the FT (proximal vs distal femoral triangle block (FTB)). Methods The study was carried out as two separate investigations: first, dissection of nine cadaver sides to verify a technique for IFCNB; second, a volunteer study with 40 healthy volunteers. The surgical midline incision for TKA was drawn bilaterally. All volunteers received an active distal FTB combined with a placebo proximal FTB on one side and vice versa on the other side. All volunteers were randomized to an active IFCNB on one side and placebo IFCNB on the contralateral side. Results Identification of IFCN was successful in all cadaver sides. Fifteen out of 20 volunteers had complete anesthesia of the incision line after IFCNB combined with proximal FTB, which was significantly higher compared with proximal FTB alone and with distal FTB+IFCNB. A gap at the anteromedial knee area was present in 2/20 volunteers with proximal FTB compared with 17/20 with distal FTB when all volunteers had active IFCNB. Conclusion Ultrasound-guided blockade of the IFCN and MFCN anesthetize the surgical midline incision and the anteromedial area of the knee relevant for TKA. In contrast, an injection at the midthigh level produces insufficient cutaneous anesthesia not covering the areas of interest. Trial registration number EudraCT: 2018-004986-15.

Addition of 8 mg dexamethasone to 0.5% bupivacaine-epinephrine significantly prolongs the duration of sensorimotor popliteal sciatic nerve blockade, and reduces pain and opioid consumption in patients after major hind foot and ankle surgery.