Adductor Canal Block
Indications: Knee surgery, Ankle/Foot surgery
Knee arthroplasty (total or revision)
Open reduction internal refixation for patellar dislocation
ACL Repair
Often used in conjunction with popliteal nerve block for procedures on the ankle/foot
Anatomy of the Adductor Canal:
The musculoaponeurotic tunnel from the apex of the femoral triangle to the adductor hiatus
Lateral border: vastus medialis
Medial border: adductor magnus and longus
Superior border: sartorius
Contents of the adductor canal:
Nerves: consistently contains the saphenous nerve (sensory branch, femoral nerve), and the nerve to the vastus medialis (mixed motor/sensory); may contain the medial femoral cutaneous nerve (sensory) and the anterior cutaneous branch of the obturator nerve (sensory)
Superficial femoral vessels
Patient Position: Patients are typically supine, with the ipsilateral leg externally rotated to allow easier access to the target zone
Technique: Probe— Linear; Needle— In-plane
Mid-thigh level (halfway between anterior superior iliac spine and superior border of the patella) for both single shot and catheter placement
Saphenous nerve usually visible as hyperechoic structure anterolateral to the superficial femoral artery (will be located more medially to the superficial femoral artery in the distal adductor canal)
In plane technique, local anesthetic deposition in the adductor canal with the saphenous nerve and femoral artery in view
Dose: 0.5 - 1.5 mg/kg of Bupivacaine or Ropivacaine (roughly 0.1 - 0.2 mL/kg).
Coverage:
An adductor canal block block (saphenous nerve) provides anesthesia to the medial aspect of the lower leg and ankle as well as the skin overlying a portion of the patella. Unlike a femoral nerve block, strength in the quadriceps is unaffected, potentially allowing early mobilization or discharge
Potential Complications:
Bleeding/hematoma formation
Infection
Intravascular injection (LAST)
Sonoanatomy
Frazer et al, 2021: retrospective chart review. 98 participants. No significant difference in quadriceps weakness at 6 months postop between adductor canal block, femoral nerve block and no nerve block groups.
Holland et al, 2020: retrospective review of adolescent patients who underwent ACL repair with either a continuous femoral nerve block or a continuous adductor canal block. 91 patients that met inclusion criteria. Mean age 15.1 years. No significant difference between oxycodone use on POD1-POD2. However, there was a statistically significant difference in oxycodone use on POD3 with more use in the continuous femoral nerve block group. No major complications in either group. Residual numbness seen in patients in both groups (3 cFNB, 1 cACB), all of which resolved within 1 year. There was no significant difference in the 6 month quadriceps function between groups.
Vora et al, 2016: review article. Adductor canal block provides equivalent analgesia to femoral nerve block for knee replacement. Recommends mid-thigh approach with 0.2% ropivacaine (or equivalent local anesthetic) with 15-30 mL of volume. No major reported complications. However, there has been report of muscle weakness following an adductor canal block.
Chen et al, 2015: Case series, 6 patients for open reduction and internal fixation for patellar dislocation. Ultrasound guided adductor canal block with 10 mL of ropivacaine 0.2% and dexmedetomidine 0.5 mcg/kg. Pain scores at 12, 24, 36 and 48 hour postoperatively. Lower pain scores in patients <50 kg. In patients >50kg, increase in pain scores at 24 hours.
Frazer, A.R., Chaussé, M.E., Held, M., St-Pierre, C., Tsai, C.Y., Preuss, R., Descoteaux, N., Chan, M., Martineau, P.A. and Veilleux, L.N., 2021. Quadriceps and Hamstring Strength in Adolescents 6 Months After ACL Reconstruction With Femoral Nerve Block, Adductor Canal Block, or No Nerve Block. Orthopaedic Journal of Sports Medicine, 9(7), p.23259671211017516.
Holland, E.L., Robbins, R.E., Low, D.K., Bosenberg, A.T., Bompadre, V. and Schmale, G.A., 2020. Comparison of Continuous Adductor Canal and Femoral Nerve Blocks for Analgesia and Return of Quadriceps Function After Anterior Cruciate Ligament Reconstruction in Adolescent Patients. Arthroscopy, sports medicine, and rehabilitation, 2(2), pp.e121-e128.
Vora, M.U., Nicholas, T.A., Kassel, C.A. and Grant, S.A., 2016. Adductor canal block for knee surgical procedures. Journal of Clinical Anesthesia, 35, pp.295-303.
Chen, J.Y., Li, N. and Xu, Y.Q., 2015. Single shot adductor canal block for postoperative analgesia of pediatric patellar dislocation surgery: a case-series report. Medicine, 94(48).
