Acta Anaesthesiol Scand 2012; 56: 357–364 © 2012 The Authors Printed in Singapore. All rights reserved Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation ACTA ANAESTHESIOLOGICA SCANDINAVICA doi: 10.1111/j.1399-6576.2011.02621.x Effects of Adductor-Canal-Blockade on pain and ambulation after total knee arthroplasty: a randomized study M. T. Jenstrup1, P. Jæger2, J. Lund1, J. S. Fomsgaard3, S. Bache3, O. Mathiesen2, T. K. Larsen3 and J. B. Dahl2 1Department of Anaesthesia, Hamlet Hospital, Frederiksberg, Denmark, 2Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Denmark and 3Department of Anaesthesia, Copenhagen University Hospital, Glostrup, Denmark Background: Total knee arthroplasty (TKA) is associated with compared with the placebo group (40 Ϯ 21 vs. 56 Ϯ 26 mg, intense post-operative pain. Besides providing optimal analge- P = 0.006). Pain was significantly reduced in the ropivacaine sia, reduction in side effects and enhanced mobilization are group during 45 degrees flexion of the knee (P = 0.01), but not at important in this elderly population. The adductor-canal- rest (P = 0.06). Patients in the ropivacaine group performed blockade is theoretically an almost pure sensory blockade. We the ambulation test, the Timed-Up-and-Go (TUG) test, at 24 h hypothesized that the adductor-canal-blockade may reduce mor- significantly faster than patients in the placebo group (36 Ϯ 17 phine consumption (primary endpoint), improve pain relief, vs. 50 Ϯ 29 s, P = 0.03). enhance early ambulation ability, and reduce side effects (sec- Conclusion: The adductor-canal-blockade significantly ondary endpoints) after TKA compared with placebo. reduced morphine consumption and pain during 45 degrees Methods: Patients aged 50–85 years scheduled for TKA were flexion of the knee compared with placebo. In addition, the included in this parallel double-blind, placebo-controlled rand- adductor-canal-blockade significantly enhanced ambulation omized trial. The patients were allocated to receive a continuous ability assessed by the TUG test. adductor-canal-blockade with intermittent boluses via a catheter with either ropivacaine 0.75% (n = 34) or placebo (n = 37) (http://www.clinicaltrials.gov Identifier: NCT01104883). Accepted for publication 17 November 2011 Results: Seventy-five patients were randomized in a 1 : 1 ratio © 2012 The Authors and 71 patients were analyzed. Morphine consumption from 0 Acta Anaesthesiologica Scandinavica to 24 h was significantly reduced in the ropivacaine group © 2012 The Acta Anaesthesiologica Scandinavica Foundation otal knee arthroplasty (TKA) is associated with blocks involving the femoral nerve may be associ- Tintense, early post-operative pain. This surgical ated with the risk of falling.7–13 Consequently, population consists primarily of elderly patients, regional anesthesia techniques with preserved often with significant co-morbidity. The post- muscle function are warranted. operative analgesic regimen should aim to reduce A number of different nerves and nerve branches morbidity and enhance functional recovery as well traverse the adductor canal (Hunter’s canal), includ- as provide efficient analgesia with minimal side ing the saphenous nerve, the nerve to the vastus effects.1 medialis, the posterior branch of the obturator Femoral and lumbar nerve blocks are effective for nerve, and in some cases, the medial cutaneous post-operative pain relief after TKA.2–5 However, nerve and the anterior branch of the obturator femoral nerve block (FNB) reduces the strength of nerve.14 Except for the nerve to the vastus medialis, the quadriceps muscle by more than 80%.6 This these branches have a sole sensory function, and adverse effect is particularly undesirable because most of them play a major role in the sensory inner- early mobilization after surgery is important in vation of the knee region. We have recently hypoth- order to enhance functional recovery and to reduce esized that administration of high-volume local immobility-related complications. In addition, anesthetic into the adductor canal [(‘adductor-canal- recent reports have shown that peripheral nerve blockade’ (ACB)] could be a useful option for post- 357 M. T. Jenstrup et al. operative analgesia after TKA.14 This hypothesis discretion of the anesthetist, and a femoral tourni- has not, however, been investigated in controlled quet was used at the discretion of the surgeon. clinical trials. The ACB was performed immediately post- The objective of this prospective, randomized, operatively. At the midthigh level, approximately double-blind, placebo-controlled study was there- halfway between the superior anterior iliac spine fore to investigate the efficacy of ACB on opioid and the patella, a high-frequency linear ultrasound consumption, pain relief and ambulation ability (US) transducer (GE Logiq e, GE, Waukesha, WI, after TKA. We hypothesized that ACB would reduce USA) was placed in a transverse cross-sectional morphine consumption (primary endpoint), and view. Underneath the sartorius muscle the femoral improve pain relief, enhance ambulation ability and artery was identified, with the vein just inferior reduce side effects (secondary endpoints) after TKA and the saphenous nerve just lateral to the artery. compared with placebo. From the lateral side of the transducer a 10-cm, 18-gauge Tuohy needle (Braun Medical, Melsungen, Materials and methods Germany) was inserted in plane, through the sarto- rius muscle. With the tip of the Tuohy needle placed After approval was obtained from the local Regional just lateral to the artery and the saphenous nerve, Ethics Committee (H-1-2009-143), the Danish Medi- 20 ml of study medication was injected to expand cines Agency (2009-017794-37), and the Danish Data the adductor canal. A 21-gauge catheter was then Protection Agency, this prospective, randomized, inserted 5–8 cm through the canula. To obtain the double-blind, placebo-controlled, parallel group correct position of the catheter tip, the catheter was study was conducted at Hamlet Hospital, Frederiks- slowly retracted during injection of a further 10 ml berg and at Glostrup University Hospital, the of study medication under US guidance, until an Capital Region of Denmark. Written informed expansion between the fascia and the vessels could consent was obtained from all subjects. The study be visualized. All blocks were performed by one of was conducted in accordance with the Helsinki Dec- three anesthesiologists (M. T. J., J. L., J. S. F.), all with larations and the guidelines for Good Clinical Prac- considerable experience in US-guided nerve blocks. tice (GCP), and was monitored by the Copenhagen Patients were randomly assigned to receive either University Hospital GCP unit. Data are presented ACB with ropivacaine 0.75% or isotonic saline. The in accordance with the CONSORT statement. The study groups were given 30 ml of ropivacaine or trial was registered at http://www.clinicaltrials.gov saline immediately post-operatively according to (NCT01104883). randomization. Additional boluses of 15 ml of ropi- From August 2010 to March 2011 all patients vacaine 0.75% or saline were administered at 6, 12 undergoing TKA at the two centers were screened and 18 h post-operatively. At 24 h post-operatively, for inclusion. Eligible participants were patients after assessment of pain, morphine consumption, scheduled for primary TKA under spinal anesthe- ambulation ability, and side effects, both the ropi- sia, aged 50–85 years, with an American Society of vacaine and the saline groups received a bolus of Anesthesiologists physical status classification of 15 ml of ropivacaine 0.75%. I–III, and a body mass index of 18–35. Exclusion Intravenous patient-controlled analgesia (PCA) criteria were inability to cooperate, inability to speak was provided with morphine, bolus 2.5 mg, lock-out or understand Danish, allergy to any drug used in time 10 min and no background infusion. If analge- the study, a daily intake of strong opioids (mor- sia was inadequate patients received an additional phine, oxycodone, methadone, fentanyl, ketobemi- bolus of 2.5 mg morphine i.v. until adequate analge- done), alcohol or drug abuse or inability to perform sia was obtained. Additional analgesics consisted of the mobilization test [Timed-Up-and-Go (TUG) oral acetaminophen 1 g and oral ibuprofen 400 mg 15 test ] pre-operatively. administered at 6-h intervals, initiated at 6 h post-operatively. Interventions Ondansetron 4 mg i.v. was administered in the Pre-medication consisted of acetaminophen 1 g case of moderate to severe nausea or vomiting, with orally 1 h before surgery. Spinal anesthesia was supplemental doses of 1 mg, if needed. induced with 2 ml 0.5% hyperbaric bupivacaine at the L3/4 interspace (alternatively at the L2/3 or Outcomes L4/5 interspaces). Sedation with propofol and intra- The primary endpoint was cumulative morphine operative fluid therapy were administered at the consumption during 0–24 h post-operatively. 358 Adductor-canal-blockade for TKA Secondary endpoints were pain at rest and during numbers, except for the last block, which only con- 45 degrees flexion of the knee, ambulation ability tained five numbers. Upon inclusion into the study assessed with the TUG test, post-operative nausea the participants were assigned consecutive numbers and vomiting (PONV), ondansetron consumption and received the study medication in the corre- and sedation. sponding boxes. All investigators, staff, and patients