Effect of Adductor Canal Nerve Block Compared to a Simulated Block on Quadriceps Strength Following Knee Arthroplasty
Condition: Knee Arthroplasty
Study type: Interventional

Summary: 
      Total knee arthroplasty (TKA) is a frequent and effective surgery for knee osteoarthritis.
      This major surgery is associated with a reduction in knee extensor muscle strength persisting
      several weeks after surgery. This decrease in strength correlates with poor functional
      recovery. Its cause is multifactorial, including a deficit of the quadriceps activation, an
      acute postoperative atrophy of the muscle and an important limitation related to
      postoperative pain.

      Peripheral nerve blocks using local anesthetics are frequently used for postoperative
      analgesia following TKA. Femoral nerve blockade reduces pain and opioid consumption and
      allows early passive mobilization after surgery. This block also facilitates functional
      recovery and allows early discharge from the hospital. However, blocks involving the proximal
      femoral nerve contribute to quadriceps weakness for the duration of nerve blockade.
      Quadriceps weakness, in turn, results in functional impairment and increases recovery time. A
      possible long-term quadriceps weakness associated with the femoral nerve block has even been
      suggested in a recently published abstract. Hence, there is a need for an alternative
      technique that could minimize postoperative pain as well as the femoral nerve block without
      causing weakness of the quadriceps muscle.

      Femoral nerve block performed at the level of the adductor canal seems to be a promising
      alternative to the classic inguinal approach of the femoral nerve block. Studies comparing
      femoral nerve block performed at the canal adductor level to the inguinal approach reported a
      similar quality of analgesia, a reduction in motor block and a better functional recovery in
      the early postoperative period in the canal adductor block group. The long-term effect of
      femoral nerve block performed at the level of the adductor canal on knee extensor strength
      after surgery remains to be studied.

      This study will assess knee extensor muscle strength (principally quadriceps muscle) at 24h,
      48h and 6 weeks following TKA in patients having a femoral nerve block at the adductor canal
      level compared to a simulated block.

      Hypothesis: The adductor canal block will allow superior recovery of knee extensor muscle
      strength when compared to a simulated block at 6 weeks after total knee arthroplasty.
    

Detailed description: 
      On arrival in the operating room, patients will be randomly assigned to receive an adductor
      canal block under ultrasound guidance or a simulated block.

      In the adductor canal block group, a 18 Gauge Tuohy needle will be inserted and its position
      in the adductor canal adjacent to the femoral artery will be confirmed using ultrasound
      guidance. Once the adequacy of the position is confirmed, the anesthesiologist will
      administer 15 mL of bupivacaine 0.25% with epinephrine in divided doses and examine the
      quality of its spread. A 20 Gauge polyamide catheter will be inserted at 2 cm in the space.
      The needle will then be withdrawn and the catheter will be fixed in place. Three mL of the
      same mixture of local anesthetics will be administered through the catheter and the
      anesthesiologist will observe the quality of its distribution.

      In the simulated block group, the insertion of the Tuohy needle and the injection of 15 mL of
      bupivacaine 0.25% with epinephrine will be simulated. The insertion of the polyamide
      catheter, the withdrawal of the needle and the injection of local anesthetics through the
      catheter will also be simulated.

      Surgery will be performed under spinal anesthesia. A standardized dose of bupivacaine and
      morphine will be administered for spinal anesthesia.

      In both groups, an infusion of local anesthetics will be initiated on arrival in the recovery
      room and will continue for the first 48 hours. To preserve the blinding in the simulated
      block group, a Luer-lock connector and a 50 mL empty pouch of intravenous fluids will be
      affixed to the catheter to collect the infused local anesthetics. The empty pouch will be
      inserted under the opaque dressing. Patients in the adductor canal block will receive an
      infusion of bupivacaine 0.125% at 12 mL/h and patients in the simulated block group will have
      an infusion of the same medication but at an infusion rate of 1 mL/h. The infusion rate will
      be hidden from the patient. Multimodal analgesia will be used in all patients.

      Patients will be asked to complete the Knee injury and Osteoarthritis Outcome Score (KOOS)
      questionnaire before and 6 weeks following surgery.

      Knee extensor muscle strength will be measured using a hand-held dynamometer pre-operatively
      and 24 hours, 48 hours and 6 weeks following surgery. Pain scores at rest and during strength
      assessment will be collected. Opioids consumption and side-effects attributable to analgesia
      will be recorded. Patients will be asked to rate their global satisfaction regarding the
      quality of analgesia 48 hours after surgery. Time to discharge will be recorded.
    

Intervention name(s): Adductor canal femoral nerve block; Simulated nerve blockade
Intervention type(s): Device; Device
Intervention description(s): A 18 Gauge Tuohy needle will be inserted and its position will be confirmed using ultrasound guidance. Once the adequacy of the position is confirmed, the anesthesiologist will administer 15 mL of bupivacaine 0.25% with epinephrine in divided doses and examine the quality of its spread. A 20 Gauge polyamide catheter will be inserted at 2 cm in the space. The needle will then be withdrawn and the catheter will be fixed in place. Three mL of the same mixture of local anesthetics will be administered through the catheter and the anesthesiologist will observe the quality of its distribution. Bupivacaine 0.125% will be administered through the catheter using an infusion pump for 48 hours. Knee extensor muscle strength, pain and side-effects will be assessed at different time-points.; The insertion of the Tuohy needle and the injection of 15 mL of bupivacaine 0.25% with epinephrine will be simulated. The insertion of the polyamide catheter, the withdrawal of the needle and the injection of local anesthetics through the catheter will also be simulated. The infusion of bupivacaine 0.125% will also be simulated for 48 hours. Knee extensor muscle strength, pain and side-effects will be assessed at different time-points.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Knee arthroplasty; Adductor canal block; Quadriceps strength