Prosthetic Knees and Hips: New Test Helps Detect Infection

About 750,000 knee and hip replacements are performed each year in the United States. An aging population with arthritis, baby boomers remaining active later in life, and the prevalence of obesity, are among the reasons that hip and knee replacements are expected to increase dramatically over the next 25 years. By the year 2030, the American Academy of Orthopedic Surgeons expects the number to rise to approximately 2.5 million.

Infection is among the possible complications associated with prosthetic knees and hips. Patients who have an infected prosthetic joint may not experience symptoms which usually occur with an infection (i.e., fever, pus). Pain may be the only clue, but an infection may not be initially suspected. By the time the infection is discovered it may be quite advanced.

Mayo Clinic researchers have discovered a new, and potentially more accurate way of detecting infection in prosthetic joints. In a study reported in the August 16 issue of the New England Journal of Medicine, the new test was used on 331 patients who were having prosthetic knees or hips surgically removed because of infection or another reason. The new diagnostic test detected 78.5 percent of infected prosthetic joints compared to 60.8 percent using a conventional approach which samples tissues around the prosthetic joint when it is removed. The new procedure uses a method known as sonication to test the surface of a prosthetic joint, once it is removed, in order to identify the bacteria which caused the infection. Sonication is the use of sound wave energy to disrupt biological materials such as bacteria.

Related Resources:

• Too Young for Joint Replacement?
• Joint Replacement: When Is the Right Time?
• Hip Replacement: What You Need to Know
• Knee Replacement: What You Need to Know
• Test Your Knowledge: Types of Joint Surgery

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