ACB v FNB for Revision TKA

• Opioid consumption[ Time Frame: 48 hours post-op ]
  Opioid requirements during hospitalization will be measured. Total opioid consumption during this time period after surgery will be standardized to morphine equivalent doses and calculated on a milligram basis for this time period or until discharge, whichever occurs first
• Pain score measurement: we will use Numeric rating scale for measurement (NRS)[ Time Frame: 48 hours post-op ]
  Pain scores on a 0-10 numerical rating scale (NRS) where 0= no pain and 10= the worst pain ever. the scores will be assessed every 8 hours from nursing documentation through 48 hours or until discharge, whichever occurs first

This is a prospective, randomized, blinded study with a parallel design and an allocation ratio of 1:1 for the treatment groups. The investigators seek to determine if femoral nerve block (FNB) improves the quality of recovery and improve postoperative analgesia compared with adductor canal block (ACBs) for patients undergoing revision total knee arthroplasty.

• Procedure: Nerve Block for pain control post-revision total knee arthroplasty
  A 20g catheter will be introduced and advanced 2-3 cm beyond the tip of the needle under ultrasound visualization. After needle withdrawal, catheter placement will be checked by visualizing local anesthetic spread under ultrasound. 0.5% ropivacaine will be used for catheter placement. At the conclusion of surgery, the catheters will be connected to a pump that will infuse ropivacaine 0.2% at 6 mL/hr with a patient controlled bolus of 5mL and a lockout of 30 minutes.

• Experimental: Adductor Canal Block
  A 20g catheter will be introduced and advanced 2-3 cm beyond the tip of the needle under ultrasound visualization. After needle withdrawal, catheter placement will be checked by visualizing local anesthetic spread under ultrasound. 0.5% ropivacaine will be used for catheter placement. At the conclusion of surgery, the catheters will be connected to a pump that will infuse ropivacaine 0.2% at 6 mL/hr with a patient controlled bolus of 5mL and a lockout of 30 minutes.
• Active Comparator: Femoral Nerve Block
  A 20g catheter will be introduced and advanced 2-3 cm beyond the tip of the needle under ultrasound visualization. After needle withdrawal, catheter placement will be checked by visualizing local anesthetic spread under ultrasound. 0.5% ropivacaine will be used for catheter placement. At the conclusion of surgery, the catheters will be connected to a pump that will infuse ropivacaine 0.2% at 6 mL/hr with a patient controlled bolus of 5mL and a lockout of 30 minutes.