Featured Research

from universities, journals, and other organizations

New Diagnostic Test For Detecting Infection In Prosthetic Joints

Date:
August 17, 2007
Source:
Mayo Clinic
Summary:
Researchers have discovered a new, more accurate diagnostic test to detect infection of prosthetic joints, potentially leading to better treatment options and patient outcomes. While most people who have their hips or knees replaced experience dramatic benefit, a small percentage require additional surgery, most commonly for infection or loosening of the prosthetic joint.

A team of Mayo Clinic researchers has discovered a new, more accurate diagnostic test to detect infection of prosthetic joints, potentially leading to better treatment options and patient outcomes.

The new method, which samples bacteria that adhere to the prosthetic surface, was tested in a study of 331 patients with prosthetic hip or knee joints who were having their prosthetic joints removed for infection or another cause. The new diagnostic test detected more of the infected cases (78.5 percent) than did the conventional approach (60.8 percent).

While most people who have their hips or knees replaced experience dramatic benefit, a small percentage require additional surgery, most commonly for infection or loosening of the prosthetic joint. The conventional method for detecting infection, which has been used for decades and is still commonly performed, samples tissue around the prosthetic joint at the time of surgery.

"The problem with the conventional method is that you need multiple tissue specimens, because the sensitivity of a single specimen is not good -- in other words, the infection might be missed with just one sample," explains Robin Patel, M.D., Mayo Clinic Professor of Medicine, who led the multidisciplinary team of orthopedic surgeons, infectious diseases physicians and laboratory researchers. "Another issue is that bacteria normally found on the skin can be picked up on the tissue specimen as it is extracted and passes through the skin, yielding a false-positive result. These same bacteria may actually cause the infection, so doctors can't always tell just by the type of bacteria detected whether the patient has an infection or not. If multiple specimens are positive for the bacteria, then this indicates that the bacteria are causing the infection."

Approximately 750,000 total hip and knee replacement surgeries are performed each year in the United States. This number is expected to increase to 2.5 million by 2030, according to a March 2006 presentation at the American Academy of Orthopedic Surgeons.

According to Dr. Patel, individuals with prosthetic joints may not know that they have an infection.

"When people think of infection, they may think of fever or pus coming out of a wound," explains Dr. Patel. "However, this is not the case with prosthetic joint infection. Patients will often experience pain, but not other symptoms usually associated with infection. Often what happens is that the bacteria that cause infection on prosthetic joints are the same as bacteria that live harmlessly on our skin. However, on a prosthetic joint they can stick, grow and cause problems over the long term. Many of these bacteria would not infect the joint were it not for the prosthesis. "

Micro-organisms associated with prosthetic joint infection are found in biofilms, which are colonies of bacteria that adhere to the prosthesis surface. Researchers initiated the study with the hypothesis that methods that sample the prosthesis surface should improve the diagnosis of prosthetic joint infection.

The new test involves surgeons removing the prosthetic joint as they normally would, placing it in a special container, and sending it to the laboratory. In the laboratory, a solution is added to the container and then the container is subjected to a combination of vortexing (shaking) and sonication (exposure to ultrasound) which has been shown to remove biofilm bacteria. Then, the bacteria, which are in the solution, are quantitatively cultured.

"If you look at the study, you'll see we found a wide variety of different types of bacteria," says Dr. Patel. "This is important to recognize, because it is ideal for the doctors to know what type of infection they are dealing with in order to treat it properly -- this determines what type of antibiotic to give, and in some cases, what type of surgery to perform."

The findings are published in the August 16 issue of the New England Journal of Medicine.

The study was funded by the Orthopedic Research and Education Foundation.


Story Source:

The above story is based on materials provided by Mayo Clinic. Note: Materials may be edited for content and length.


Cite This Page:

Mayo Clinic. "New Diagnostic Test For Detecting Infection In Prosthetic Joints." ScienceDaily. ScienceDaily, 17 August 2007. <www.sciencedaily.com/releases/2007/08/070816091028.htm>.
Mayo Clinic. (2007, August 17). New Diagnostic Test For Detecting Infection In Prosthetic Joints. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2007/08/070816091028.htm
Mayo Clinic. "New Diagnostic Test For Detecting Infection In Prosthetic Joints." ScienceDaily. www.sciencedaily.com/releases/2007/08/070816091028.htm (accessed July 28, 2014).

Share This




More Health & Medicine News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
West Africa Gripped by Deadly Ebola Outbreak

West Africa Gripped by Deadly Ebola Outbreak

AFP (July 28, 2014) The worst-ever outbreak of the deadly Ebola epidemic grips west Africa, killing hundreds. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins