Risk of Falling After CFNB Versus ACB
Condition: Falls; Total Knee Arthroplasty (TKA); Osteoarthritis
MeSH terms: Osteoarthritis
Study type: Interventional

Summary: 
      Blocking sensation from the femoral nerve by injecting local anesthetic around the nerve
      plays an important role in pain control after total knee replacement. However, femoral nerve
      block has been associated with increased risk of falls due to weakness of the thigh muscle.
      This prospective, randomized controlled trial asks the question whether blocking the more
      distal branch of the femoral nerve (saphenous nerve) will result in less muscle motor block,
      and thus less risk of falls. The study also aims to compare pain control after both
      techniques.
    

Detailed description: 
      If the patient is willing to participate and signs the consent, he/she will be randomized to
      one of the two treatment groups:

        1. Femoral nerve block

        2. Adductor canal block

      The standard of care anesthesia regimen for this surgery is as follows:

      All Patients will receive their Multimodal Perioperative Pain Protocol (MP3) medication as
      per routine care in the patient receiving area. All blocks are performed in the pre-operative
      holding area with standard ASA monitors applied. Typically, patients receive 1-2 mg of
      midazolam and 50-100 mcg of fentanyl for sedation during the placement of the block. Standard
      operating procedure of the block room will be followed. Block time out will be preformed
      according to standard operating procedure. All blocks will be done under ultrasound guidance.
      Sonosite (S nerve) machine will be used with a high frequency linear (HFL) US probe with 6-13
      MHZ frequency. Both CFNB and ACB will take be performed according to the SOP in the
      investigators department.

      For CFNB: Images of the femoral nerve will be obtained in the short axis. 1% lidocaine will
      be used for local infiltration of the skin. A 2 inch 18 G touhy needle ( B Braun) will be
      advanced in plane under US guidance . Confirmation may take place with Quadricpes muscle
      twitches and patella movement between 0.3 and 0.4mA (2Hz; 0.1ms). A bolus of 20 ml of
      Ropivicaine 0.5% will be injected. A non stimulating catheter will be advanced through the
      needle to a distance of 3-4 cm beyond the needle tip. Catheter will be secured in place using
      benzoin, Steristrips, and a tegaderm.

      For the ACB: ultrasound survey at the medial part of the thigh will take place, halfway
      between the superior anterior iliac spine and the patella. In a short axis view, the femoral
      artery will be identified underneath the sartorius muscle, with the vein just inferior and
      the saphenous nerve just lateral to the artery. The needle will be introduced in-plane and 2
      to 3 mL of LA bolus (0.2% ropivicaine) will be used to verify correct placement of the needle
      in the vicinity of the saphenous nerve in the adductor canal. A bolus of total volume of 20
      ml of Ropivicaine 0.5% will be injected through the needle. The catheter will then be
      introduced and advanced 2-3 cm beyond the tip of the needle.

      At the conclusion of surgery a large obaque dressing will be applied from the femoral crease
      to the mid thigh region so that the catheter location will be concealed. Both catheters will
      be connected to a pump that will infuse local anesthetic. Ropivicaine 0.2% at 8 ml/hour.
      There is usually a period of time before the patient transport to the operating room during
      which the investigators will be able to evaluate if the block is effective and sufficient for
      surgery.

      Patients will receive either general or spinal anesthesia in the operating room. All patients
      will receive prophylaxis for nausea and vomiting during surgery. Regimen for prophylaxis
      include a single dose of dexamethasone after induction of anesthesia and a single dose of
      Ondansetron 20 minutes before recovery from anesthesia. This study is not deviating from the
      standard of care anesthetic regimen for this surgical procedure at Penn Presbyterian Medical
      Center. Only the type of blocks will be different between the two groups.

      Postoperative analgesia All PACU analgesia will follow standard of care protocol for post
      operative care at PPMC. Hydromorphone 0.2 mg iv q5 minutes as necessary. The infusion of the
      local anesthetic will start in the PACU.

      In the PACU, patients are assessed for pain with the Visual Analog Scale (pain scale of 1 to
      10) at routine time points for the duration of their stay. The worse VAS score will be
      recorded.

      Postoperative Analgesia

      Postoperative analgesia will follow the MP3 protocol. The protocol includes administration of
      around the clock acetaminophen, Celebrex, gabapentin, immediate and extended release
      oxycodone.
    

Intervention name(s): adductor canal block; femoral nerve block
Intervention type(s): Procedure; Procedure
Intervention description(s): ultrasound guided saphenous nerve block in the adductor canal; ultrasound guided femoral nerve block
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: femoral nerve block; adductor canal block; tinetti score; 2- Results to time to up and go (TUG ) test; 3- Results to Tinetti test; 4- Ambulation distance; 5- Pain scores at rest and with movement