Navigation Links
New test for joint infection could spare some patients an unnecessary procedure
Date:3/3/2008

A potential diagnostic test that could help surgeons confirm or rule out the presence of infection-causing bacteria in prosthetic joints that require surgical revision has been developed by researchers at the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the National Institutes of Health (NIH). Such a test could spare a subgroup of people who need the surgery a time-consuming and costly treatment for infection, while helping to ensure that people who need the procedure get it. The test is described in the March issue of the Journal of Bone and Joint Surgery.

Each year, hundreds of thousands of joint replacement surgeries are performed in this country. And each year, thousands of them must be revised (the prosthetic joint must be removed and replaced) due to severe pain and swelling. These symptoms are often due to infection, says Rocky S. Tuan, Ph.D., chief of NIAMS' Cartilage Biology and Orthopaedics Branch.

The standard treatment for suspected infection is to remove the joint prosthesis and replace it with a spacer that has been impregnated with antibiotics. After about six weeks, patients must undergo another surgery to remove the spacer. Only then can the surgeon implant the new prosthesis.

The problem with this approach is that confirming the presence of infection-causing bacteria is an inexact science. Currently, doctors check for infection by culturing a sample of the joint fluid. A positive culture confirms live bacteria, making spacer surgery a certainty. A negative culture, however, does not necessarily mean there is no infection. In fact, Tuan says that estimates of the false negative rate for joint cultures in revision surgeries range from 27 percent to 50 percent. But because failure to treat an infected joint could lead to severe infection and limb amputation, spacer surgery is sometimes performed for safety's sake even when infection test results are inconclusive.

To get around the false-negative problem, Tuan and his colleagues developed a way to test for joint infections using polymerase chain reaction (PCR), which detects the presence of bacterial DNA. However, this approach proved to have pitfalls, too. It picked up all bacteria even dead or dying bacteria that cannot perpetuate infection thereby giving false positives.

Tuan says this new problem led them to expand their PCR approach by testing for bacterial messenger ribonucleic acid (mRNA). "When bacteria are dying, their mRNA is one of the first things to go," he says. As a result, the researchers hypothesized that a good mRNA test would not only detect bacteria, but would likely tell them if any bacteria they detected were still viable. Unlike DNA, mRNA is not directly quantifiable by known techniques, so the mRNA test that Tuan's group developed employs a process called reverse transcription PCR (RT-PCR) to convert the mRNA into DNA for measurement.

Tuan's group tested the validity of their new method by introducing bacteria into infection-free joint fluid to simulate infection. To ensure that the bacteria were indeed present, they used the PCR test, which accurately showed the amount of bacterial DNA. The researchers then treated the joint fluid cultures with potent antibiotics designed to kill off the bacteria. As expected, the PCR-DNA test still showed that the fluid contained plenty of bacteria, but when the group analyzed the cultures with the RT-PCR test for mRNA, they found that the viable bacteria population was declining.

Now Tuan's team is recruiting 50 people who need joint revision for a clinical trial that will involve testing patients' joint fluid for bacteria and then following them for 6 months to a year after surgery. They hope that the results from this study will validate the protocol to identify or rule out infections before a person begins a surgical revision.

Tuan would like to be able to tell patients who need infection treatment, "There is a really bad infection and we know what to do."

"But we also want to tell the person without infection that it's O.K. to put in a revision joint. That saves the spacer, the additional surgery and its associated risk, and 6 weeks of being laid up," Tuan says.


'/>"/>

Contact: Trish Reynolds
reynoldsp2@mail.nih.gov
301-496-8190
NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases
Source:Eurekalert

Related medicine news :

1. MaxLife Fund Corp. and Capital Growth Planning Inc., sign a joint venture agreement
2. International Federation of Sports Medicine Selects Celadrin(R) Topical Cream as its First and Only Official Joint and Muscle Topical Cream
3. Reynolds American Subsidiary to Receive Payment Following Gallaher Joint-Venture Termination
4. BioMed Realty Trust Joint Venture Enters Into New $245 Million Construction Loan and Extends Term of Existing Loan Facility
5. Joint Commission Alert Shines Light on Preventing MRI Accidents, Injuries
6. Joint Commission, National Quality Forum Now Accepting Applicants for the 2008 John M. Eisenberg Patient Safety and Quality Awards
7. Laser Energetics Provides Joint Venture Update to Shareholders
8. LiquidAgents Healthcare, LLC Awarded Accreditation from the Joint Commission
9. NutraCea Forms Joint Ventures With HerbalScience to Develop Nutraceutical Extracts and Pharmaceutical Chemistries From Stabilized Rice Bran
10. Joint Commission International Achieves Accreditation from ISQua
11. Grubb & Ellis Healthcare REIT Acquires Chesterfield Rehabilitation Center in Chesterfield, Missouri in a Joint Venture with Duke Realty
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/25/2016)... ... June 25, 2016 , ... Experts from the American ... Annual Research Meeting June 26-28, 2016, at the Hynes Convention Center in Boston. ... including advance care planning, healthcare costs and patient and family engagement. , AIR ...
(Date:6/25/2016)... ... June 25, 2016 , ... "With 30 hand-drawn hand gesture ... said Christina Austin - CEO of Pixel Film Studios. , ProHand Cartoon’s package ... Final Cut Pro X . Simply select a ProHand generator and drag it ...
(Date:6/25/2016)... City, Oklahoma (PRWEB) , ... June 25, 2016 ... ... helping both athletes and non-athletes recover from injury. Recently, he has implemented orthobiologic ... the Oklahoma City area —Johnson is one of the first doctors to perform ...
(Date:6/24/2016)... ... 24, 2016 , ... A recent article published June 14 on ... article goes on to state that individuals are now more comfortable seeking to undergo ... such as calf and cheek reduction. The Los Angeles area medical group, Beverly Hills ...
(Date:6/24/2016)... ... 24, 2016 , ... Marcy was in a crisis. Her son James, eight, was out of ... verbally and physically. , “When something upset him, he couldn’t control his emotions,” remembers Marcy. ... throw rocks at my other children and say he was going to kill them. ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... and SAN CLEMENTE, Calif. , June 24, 2016 ... mobile pulmonary function testing company, is now able to perform sophisticated ... by ndd Medical Technologies , Inc. Patients ... hospital-based labs.  Thanks to ndd,s EasyOne PRO ® , ARL patients ... get any needed testing done in the comfort of her own ...
(Date:6/24/2016)... June 24, 2016   Pulmatrix, Inc ., (NASDAQ: ... innovative inhaled drugs, announced today that it was added ... reconstituted its comprehensive set of U.S. and global ... is an important milestone for Pulmatrix," said Chief Executive ... awareness of our progress in developing drugs for crucial ...
(Date:6/23/2016)... , June 23, 2016  MedSource announced today ... its e-clinical software solution of choice.  This latest ... possible value to their clients by offering a ... preferred relationship establishes nowEDC as the EDC platform ... MedSource,s full-service clients.  "nowEDC has long been a ...
Breaking Medicine Technology: