Better Pain Relief After Knee Replacement Surgery?

Study suggests injected drug might ease pain while maintaining mobility, but more research is needed

By Mary Elizabeth Dallas

Tuesday, December 30, 2014

Related MedlinePlus Pages

TUESDAY, Dec. 30, 2014 (HealthDay News) -- Postoperative pain is always a concern after knee replacement surgery, but a new study suggests a strategy that might give patients another way to ease discomfort.

Researchers at Henry Ford Hospital in Detroit note that the painful recovery process following knee replacement surgery is a persistent problem.

However, the research team found that injecting a newer, long-acting numbing medicine, known as liposomal bupivacaine, into the area surrounding the knee helps patients recover more quickly and boosts their satisfaction with the procedure.

"Patients had pain relief for up to two days after surgery and better knee function compared with the traditional method," said the study's senior author, Dr. Jason Davis, a joint replacement surgeon at Henry Ford West Bloomfield Hospital, in a hospital news release.

The study involved more than 200 patients who underwent knee replacement surgery and were then tracked for pain control during the first two days after their procedure.

Half of the patients received traditional pain control, in which a common numbing medicine is injected via a pump into the groin area. Although this method can cause leg weakness, it prolongs pain control for two days after surgery, the researchers said.

"Pain control [using this method] came at the price of weakness and made patients somewhat tentative when walking during their hospital stay," Davis noted.

The rest of the patients received the liposomal bupivacaine injection, targeted to the site of their surgery. Unlike the traditional pain control method, the newer, long-acting numbing medicine enabled patients to begin walking comfortably just hours after surgery, the study showed.

This technique "optimizes pain control early on," said Davis. "Function-wise, it was a lot easier for patients to move around more confidently. In the past decade, we've made major advancements in pain control for knee replacement surgery. This option is a promising, viable one for our patients."

Two experts not connected to the study had mixed opinions about the results.

"Innovative approaches to pain control have markedly improved the early recovery after knee replacement," said Dr. Matthew Hepinstall, an orthopedic surgeon at Lenox Hill Hospital in New York City.

"This study confirms prior studies showing that local anesthetic injections can provide analgesia similar to nerve blocks after knee replacement, without the delayed rehabilitation that some patients experience with femoral [leg] nerve blocks," he said.

But Hepinstall stressed that only further research will let doctors know for sure that the more expensive liposomal drug is better than conventional methods at reducing postoperative pain.

Dr. Jan Koenig is chief of joint replacement surgery at Winthrop-University Hospital in Mineola, N.Y. He said that one "underreported problem with the liposomal bupivacaine time-release analgesia is that we see a lot of rebound pain about day three when it wears off."

The study was presented recently at the American Association of Hip and Knee Surgeons annual meeting in Dallas. Findings presented at medical meetings are typically considered preliminary until published in a peer-reviewed journal.

SOURCE: Matthew Hepinstall, M.D., orthopedic surgeon, Lenox Hill Hospital, New York City; Jan A. Koenig, M.D., chief of joint replacement surgery and director, Computer Assisted and Robotic Orthopedic Surgery, Winthrop-University Hospital, Mineola, N.Y.; Henry Ford Health System, news release, Dec. 22, 2014

HealthDay