Comparison Between 3 Solutions of Bupivacaine of Adductor Canal Block for Anterior Cruciate Ligament Reconstruction
Comparison Between 3 Solutions of Bupivacaine of Adductor Canal Block for Anterior Cruciate Ligament Reconstruction
Adductor canal block (ACB) is a new technique gaining acceptance as an alternative analgesic
 method of femoral nerve block (FNB) following knee surgery. The advantage of ACB is its
 dominant sensory nerve block effect. It preserves quadriceps muscle strength compared with
 the FNB. This will serve as potential gain for early rehabilitation and thereby functional
 outcome. Adequate direct injection of local anesthetic into the canal will block four nerves:
 the saphenous nerve, the nerve to the vastus medialis, the medial femoral cutaneous nerve,
 and the terminal end of the posterior division of the obturator nerve. Anterior cruciate
 ligament reconstruction (ACLR) is often associated with postoperative severe pain.
 Postoperative early rehabilitation is the primary focus to restore pre-injury status and is
 an essential part of the full recovery, especially that this rehabilitation extents over a 6
 month period. Early elimination of pain is necessary to achieve this goal. However, there are
 no clear conclusive clinical reports defining the adequate analgesic volume-dosage of local
 anesthetic for ACB for postoperative ACL pain management. The investigators speculated that
 volume-dosage manipulation play key role in the effective of ACB for postoperative pain. The
 investigators conducted this prospective, randomized, observer-blinded trial to compare 3
 combinations of volume and dosage of 0.25 % bupivacaine for US-guided ACB. The first aim of
 the investigation is to compare the analgesic effect of ACB 0.25% bupivacaine of the 3 doses
 as assessed by the visual analog scale (VAS) pain scores. The second aim were duration of
 analgesia, as defined by first demand for analgesia, and subsequent 24-h consumption.
 Physiotherapy tolerance and time to discharge were evaluated. Side effects were also
 assessed.
After institutional review board approval and informed written consent, 90 males patients,
 elective unilateral arthroscopic anterior cruciate ligament reconstruction surgery under
 general anesthesia, The investigators enrolled adult male patients aged 18 to 50 yr, with
 American physical classification (ASA) I, II body mass index ≤ 35 kg/m2 and surgery lasting
 less than 2 h. Exclusion criteria were: infection at the side at the procedure site, patients
 with diabetes mellitus, intake of any analgesic during the last 48h, history to local
 anesthetics allergy.

 After arrival in the operating room, an 18-gauge intravenous in the upper limb catheter and
 ASA standard monitoring was placed. Standard intravenous premedication (3 mg of midazolam and
 50 mcg of fentanyl) was given to all patients and supplemental oxygen was administered via
 facemask (5 L/min) throughout the block period. All Patients were randomly allocated to
 received an ultrasound-guided (GE Logic; GE, USA) ACB with 0.25% bupivacaine 1 of 3
 solutions: group 1 (G20) 20 ml, group 2 (G25) 25 ml and group 3 (G30) 30 ml. ACB was
 performed in supine position at the mid-thigh level with leg slightly rotated externally.
 After skin sterilization, a 100-mm 21Gauge needle inserted in-plane through the sartorius
 muscle and fascia and next to the femoral artery into the adductor canal. Three anesthesia
 operators participated in the study: the first operator performs all US-guided needles
 insertion, the second operator perform the injection of the local solution. Blinding of the
 first operator was ensured as follow: (i) the first operator was unaware of volume-dose
 injected with his back toward to the second operator. (ii) the second operator using opaque
 syringes. The solution was injected in increment doses after negative aspiration to avoid
 intravascular injection. The blinded third operator performed the postblock assessment of
 sensory block and motor blockade flowing the block placement. All patients were evaluated for
 block success by checking pinprick and cold sensation in the saphenous distribution on the
 lower medial leg using a 25-gauge needle and a 3-point scale (0 = normal sensation, 1 = cold
 touch without pinprick, and 2 = absence of sensation). Successful blockade was defined as a
 change from normal sensation at baseline (0) to a score of 1 or 2. Sensation was tested at 15
 and 30 minutes after nerve block and if block success was not achieved after 30 min, the
 operator consider the block as failure. Motor assessment was performed every 15 min up to 60
 mn using a handheld isometric force electromechanical dynamometer (MicroFET2; Hoggan Health
 Industries Inc., USA) for quadriceps muscle power evaluation. Before the operation, all
 patients received instructions for using a 100-mm VAS score (with 0 = no pain, to 100 = the
 worst imaginable pain). Hereafter, all patients received standard general anesthesia and were
 induced with propofol (2.5 mg/kg), cisatracurium (0.2 mg/kg) and fentanyl (0.002 mg/kg) and
 maintained with nitrous oxide 50% in oxygen and sevoflurane. No other supplementary analgesic
 medication was given during the operation after the first dose of fentanyl. During
 anesthesia, controlled ventilation was performed via an endotracheal tube. Before surgical
 incision, a thigh pneumatic tourniquet on the same side as the surgery, at a pressure of 300
 mm Hg, was applied to all patients. The same surgeon performed all surgical procedures using
 a standard surgical technique.

 After the end of anesthesia, patients were transferred to the post-anesthesia care unit
 (PACU). Arrival at PACU was recorded as time zero. The VAS was assessed at predetermined
 intervals after surgery (0, 15, 30, 45, 60, 90, 120 min) and following PACU discharge at 4,
 6, 12, and 24 h. In PACU, when the VAS was greater than 4, IV morphine was titrated every
 5min by 3mg. Pain was assessed every 5 min until pain relief, defined as a VAS ≤ 4. The
 modified Aldrete score were used to assure safe PACU discharge. Following PACU discharge, the
 first 24-h analgesia consisted of Pethidine 25 to 50 mg IV infusion repeated every 2 to 4 h
 as required. VAS score measurement in PACU and the first 24 postoperatively were assessed.
 PACU Morphine consumption and subsequent 24 -pethidine consumption were recorded. In
 addition, Time to discharge and the tolerance of physiotherapy as evaluated using VAS 10
 points-scale were assessed : 0 - 3 = easy physiotherapy well tolerated rated as 1 , 4 - 6 =
 physiotherapy is tolerated with moderate pain rated as 2 and 7 - 10 = physiotherapy is
 painful and not tolerated rated as 3 . Systemic side effects of analgesia were also reported.
Inclusion Criteria:

 -  American ASA I, II

 -  body mass index ≤ 35 kg/m2

 -  surgery time ≤ 2 hours

 Exclusion Criteria:

 -  Infection at the side at the procedure site,

 -  Patients with diabetes mellitus,

 -  Intake of any analgesic during the last 48h,

 -  History to local anesthetics allergy