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Saphenous Nerve Block vs. Femoral Nerve Block for Total Knee Arthroplasty: A Comparative Effectiveness Study in Bilateral Total Knee Arthroplasty Patients

IRB Number: 2012-033

November 22, 2011

Institutional Review Board, Hospital for Special Surgery

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Principal Investigator

Stavros G. Memtsoudis, MD, PhD


David H. Kim, MD
Mary F. Chisholm, MD
Kethy M. Jules-Elysee, MD
Yan Ma, MD
Alejandro Gonzalez Della Valle, MD
Lazaros Poultsides, MD
Thomas P. Sculco, MD
Thomas Danninger, MD
Carey Ford
Jodie Curren, RN
Isabelle Kao
Heather Reel
Daniel Yoo


Our study will compare the use of saphenous nerve blocks performed at the adductor canal versus femoral nerve blocks for total knee replacements in the same patient undergoing a bilateral procedure. We hypothesize that the saphenous nerve block performed at the level of the adductor canal provides adequate pain relief without significantly compromising muscle strength, enabling patients to mobilize early and possibly be discharged earlier to the rehabilitation center.
We will enroll a total of 60 patients. Before and after surgery, we will assess pain levels and motor strength of the operative legs by using a hand held dynamometer. We will also record patients’ pain scores, physical therapy progress and satisfaction up to 48 hours.
If our study proves the saphenous nerve block to be an effective method of postoperative pain control without compromising quadriceps strength, it would be seen as a better alternative to femoral nerve blocks. 

Inclusion/Exclusion Criteria

Inclusion Criteria
All patients ages 40-80 undergoing primary bilateral total knee arthroplasty
Planned use of neuraxial anesthesia
Ability to follow study protocol

Exclusion Criteria
Contraindication to a spinal or epidural anesthetic
Not candidate for bilateral total knee arthroplasty
Chronic opioid use (defined as daily or almost daily use of opioids for >3 months)
Hypersensitivity and/or allergy to local anesthetics
Intraoperative use of any volatile anesthetic
Patients with a pre-existing neuropathy on the operative limb
      - Contraindication to a femoral nerve block or saphenous nerve block
      - Allergy to any of the study medications
      - ASA Class 4-5
      - Non-English speaking patients