New Technique Reduces Pain After Knee Replacement

Infusion of a local anesthetic in the adductor canal during knee replacement surgery reduced postoperative pain and improved the ability of patients to get up and move following surgery.

For patients undergoing total knee replacement, one of the biggest concerns is: Will I be able to handle the pain? Total knee replacement, also know as total knee arthroplasty, usually requires local anesthesia during surgery and a course of analgesics following surgery (usually opioids and non-steroidal anti-inflammatory agents). But one of the biggest concern following surgery is: How quickly can I begin moving and start rehab?

Some pain specialists have argued that patient do better if they experience less pain immediately after surgery. Less pain equals better outcomes. So in order to study the best pain treatments to use both before and during surgery, investigators have looked at perioperative techniques—such as nerve blocks and local infiltration of analgesics at the surgical site.

A new study from Virginia Mason Hospital in Seattle, Washington, has found that a specific nerve block technique that avoids the femoral nerve, called the adductor canal block, results in the need for less morphine and a potentially speedier recovery for orthopedic surgery patients. The study was published in the June edition of Anesthesia & Analgesia, the publication of the International Anesthesia Research Society.

How the Study Was Performed

The study involved 80 patients undergoing total knee replacement. It concluded that continuous infusion of a local anesthetic  0.2% ropivacaine) through a catheter in the adductor canal of the mid-thigh—rather than higher up near the femoral nerve—provides better pain control and prevents temporary weakness of the leg muscles. This allows recovering patients to walk sooner with less weakness in the legs, resulting in improved physical therapy participation. Patients in the study also needed less morphine (opioid) to control post-surgery pain.

Virginia Mason anesthesiologists Neil Hanson, MD, and David Auyong, MD, were members of the research team and co-authors of the article. “No one in the world has shown all these possible outcomes in the same study with the adductor canal technique,” Dr. Hanson said in a release from the Virginia Mason.

Dr. Auyong added, “Use of the adductor canal for pain-block infusion appears to improve safety and clinical outcomes, and reduces the length of time needed for hospitalization. All patients now get this nerve block at Virginia Mason as part of our standard work for knee replacement surgery.”


Updated on: 05/29/14