Saphenous Nerve Block Versus Femoral Nerve Block for Total Knee Arthroplasty

Study Overview
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Brief Summary
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Currently, the regional anesthetic standard of care for total knee replacement surgery is combined spinal/epidural, with or without a femoral nerve block, or FNB. Lasting approximately 18 hours, the FNB works by numbing the femoral nerve (and its branches), which is the major nerve controlling the knee joint. The femoral nerve also provides movement and sensation. While this regional anesthetic technique offers significant postoperative pain relief, it is possible that it may cause muscle weakness and increase patients' recovery time. Hence there is a need for an alternative technique, one that may help minimize postoperative pain as effectively as the FNB, while not causing weakness of the quadriceps muscle. The saphenous nerve, a branch of the femoral nerve, provides sensation to the knee. Thus it is hypothesized that by blocking or anesthetizing the saphenous nerve with local anesthetic closer to where it branches off, the area around and below the knee will feel numb. Yet unlike with the FNB, the quadriceps muscle itself will still be able to function. Patients will be randomized to receive FNB or saphenous nerve block. Quadriceps strength will be tested using a dynamometer before surgery (baseline), 6-8 hours following anesthesia administration, and on postoperative days 1 and 2. It is hypothesized that patients who receive FNB will experience a 50% decrease in quadriceps strength compared to baseline.

Official Title
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Saphenous (Adductor Canal) Nerve Block Versus Femoral Nerve Block for Total Knee Arthroplasty: A Novel Approach for Postoperative Analgesia

Conditions
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Total Knee Arthroplasty

Intervention / Treatment
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* Procedure: Study Group: Experimental
* Procedure: Control Group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients ages 18-90 undergoing primary unilateral total knee arthroplasty Planned use of neuraxial anesthesia Ability to follow study protocol American Society of Anesthesiology (ASA) Class 1-3 Exclusion Criteria: Contraindication to a spinal or epidural anesthetic 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 Non-English speaking patients

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental<br>Saphenous (Adductor Canal) Nerve Block | Procedure: Study Group: Experimental<br>* The study group will receive the saphenous nerve block, at the level of the adductor canal. The block will be under ultrasound guidance. The local anesthetic will be 15 ml of 0.5% bupivicaine. The study group will also receive a combined spinal epidural, with 2.5 ml of 0.5% bupivacaine as the spinal agent. Additional drugs include anti-emetics, specifically Ondansetron (4 mg).<br>* Other names: Saphenous (Adductor Canal) Nerve Block;|
| Active Comparator: Control<br>Femoral Nerve Block | Procedure: Control Group<br>* The control group will receive the femoral nerve block. The block will be under ultrasound guidance. The local anesthetic will be 30 ml of 0.25% bupivicaine. The control group will also receive a combined spinal epidural, with 2.5 ml of 0.5% bupivacaine as the spinal agent. Additional drugs include anti-emetics, specifically Ondansetron (4 mg).<br>* Other names: Femoral Nerve Block;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quadriceps Muscle Strength | Measurements were made by a handheld dynamometer while patients perform isometric exercises. Results are presented in kilogram-force (kgF) units. One kgF is equal to 9.80665 N. | 48 hours following administration of anesthesia. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total Opioid Usage | Opioid consumption data were collected and converted to oral morphine equivalents. | Postoperative day 4. | 
| NRS Pain Scores at Rest | Patients rated pain on a scale of 0-10, with 0 representing no pain and 10 representing worst pain. | Postoperative day 4. | 
| Patient Satisfaction With the Nerve Block. | Patient satisfaction was measured on a 0-10 scale (0=not satisfied; 10=very satisfied). | 24 hours following administration of anesthesia. | 
| Incidence of Postoperative Complications. |  | Postoperative day 4. | 
| Total Length of Hospital Stay |  | Total length of hospital stay | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Total Knee Replacement, Regional Anesthesia, Quadriceps, Muscle Strength, Muscle Strength Dynamometer, Quadriceps muscle strength after regional anesthesia for TKA