Conditions: Arthroplasty, Replacement, Knee Nerve Block
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 165
Healthy volunteers: yes

Brief summary:
The purpose of this study is to further investigate the efficacy of adductor canal nerve blocks for pain management after total knee replacement. Specifically we are studying adductor canal nerve blocks in conjunction with epidural anesthesia, which is a combination that has not been extensively researched before. Our question is whether combining these modalities will enhance patient satisfaction after surgery and accelerate patients' readiness to discharge.

Detailed description:
Knee replacement surgery has become increasingly more common in the United States with hundreds of thousands of surgeries performed yearly across the country. Despite that, there is no consensus "standard of care" for optimum pain control regimen after surgery. Pain management after TKA ranges from local tissue injections and patient controlled anesthesia to regional nerve blocks to neuraxial anesthesia. Although regional anesthesia has become more common and widespread, there are wide variations depending on practice setting (academic versus private), equipment available (adductor nerve blocks require ultrasound guidance), level of training of the anesthesiologists and patient selection, among other factors. Another part of the reason for the wide variations in practice is the lack of literature demonstrating clear effectiveness or superiority of one technique over another.

To date adductor canal nerve blocks have been mainly studied in comparison with femoral nerve blocks in terms of their efficacy in controlling pain and their ability to preserve motor function. Adductor canal nerve blocks have been shown in the literature to be an effective method for postoperative pain control in total knee replacement surgery. One of the unique benefits of this particular technique is that the adductor canal nerve block is primarily a sensory block, thereby controlling pain without impairing motor strength. This is useful for total knee replacement surgery as pain is controlled while quadriceps muscle strength is preserved. With well functioning muscles patients are able to fully participate in physical therapy with less strength impairment and reduced risk of falling.

It is our aim to investigate one multimodal approach that combines the strengths of two proven pain management techniques and thereby improve overall postoperative pain control and patient satisfaction. Our hope is to establish a protocol that is safe and effective for patient care.

Arms:
arm 1: Patients randomized to the sham catheter will have a sham catheter placed on the skin and obscured with an opaque dressing and attached to a functional pump which will not be turned on. arm 2: Patients will receive a continuous adductor canal block placed under ultrasound guidance under the supervision of an attending physician who is fellowship trained.

Interventions: intervention 1: Adductor Canal Nerve Block Catheter intervention 2: Adductor Canal Nerve Block Sham Catheter intervention 3: Bupivacaine
Intervention descriptions: intervention 1: ACNB catheter will be placed by anesthesia residents under the supervision of board-certified anesthesiologists familiar with regional anesthesia techniques, who are part of the anesthesia pain service. They will be performed at the bedside, aseptically, with the patient's vital signs monitored throughout the procedure. 1% lidocaine will be infiltrated in the skin and subcutaneous tissues overlying the adductor canal as visualized on ultrasound. Via a 17 gauge touhy needle a closed tip non-stimulating, epidural catheter will be placed after 1% lidocaine is used to hydrodissect the space lateral to the superficial femoral artery within the adductor canal. The catheter will be secured to the skin. All catheters will be connected to infusion pumps with opaque plastic bags covering the pumps. The functional ACNB pumps will run 8cc/h. intervention 2: Patients randomized to the sham catheter will have a chlorhexidine prep of the skin and ultrasound examination of the adductor canal on postoperative day #1. To minimize patient risk, a wooden applicator will be used to apply 10 seconds of pressure to the leg followed by catheter securing to the skin with the same tegaderm and paper tape dressing used on functional catheters. All catheters will be connected to infusion pumps with opaque plastic bags covering the pumps. The sham catheter pumps will not be turned on. intervention 3: In the functioning continuous adductor canal block, 0.125% bupivacaine will be infused at a rate of 8cc/hr.

Protocol document: