Analgesic Value of Adductor Canal vs Femoral Block After Total Knee Arthroplasty

Evaluation of the Comparative Analgesic Value of Adductor Canal Block Versus Femoral Block Following Total Knee Arthroplasty

An observational study of the effect of femoral nerve block in addition to an adductor canal block for pain following total knee arthroplasty.

Subjects undergoing total knee arthroplasty will receive a preoperative adductor canal block with continuous catheter. Following a standardized general anesthetic for the procedure, subjects will be asked to rate their pain using the NRS-11 pain scale in the recovery room. Once the pain is reported at a 5/10 or above, a femoral nerve block will be performed using either 2% chloroprocaine or saline placebo (randomized). Pain scores are then evaluated over the next 30 minutes by a blinded investigator to determine if the femoral block adds any additional analgesic benefit over an adductor canal block.

Inclusion Criteria:

• Patients scheduled for elective total knee arthroplasty
• ASA Physical Status I-III
• BMI 18-40 kg/m2

Exclusion Criteria:

• Inability to cooperate with protocol
• Inability to understand or speak English
• Allergy to any local anesthetic
• Chronic opioid consumption/abuse (30 or more morphine mg equivalents/day)
• Contraindication to adductor canal or femoral nerve block