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Patient factors do not significantly influence infection risk during orthopedic surgery
Bacteria shed in the OR causes contamination and, ultimately, infection during TKA and THA.
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The number one way for a total knee arthroplasty patient to develop infection is a contaminated operating room, while predisposing patient factors, such as obesity and diabetes, do not significantly influence the infection risk.
Merrill A. Ritter, MD, of the Center for Hip and Knee Surgery in Mooresville, Ind., has studied surgical site infection for the past 15 years and follows two main principles for reducing infection risk: fewer people in the operating room and applying environmental controls.
Source: Ritter MA |
Because people shed 1,000 to 10,000 viable bacteria per minute, reducing the number of people in the OR reduces the bacteria levels in the environment. In addition, �if you have something that controls the environment, like ultraviolet light or horizontal laminar flow then that [will also] help,� Ritter told Orthopedics Today.
In a recent study, Ritter and his colleagues also found that no patient factors had any significant effect on infection. �Direct correlations are noted between sepsis and environmental contamination. Things that don�t affect [infection risk] are the head cover, mask, conventional gown, shoe covers and body exhausts on just the OR team,� Ritter said at the 7th Annual Current Concepts in Joint Replacement Spring 2006 Meeting.
In the literature, documented infection risk factors include obesity, diabetes, malignancies and immune deficiencies, such as HIV, Ritter said. But in a review of all total knee replacements at the Center for Hip and Knee Surgery over 35 years, Ritter and his colleagues found no significant infection risk factors.
Surgeons at the center saw 17,561 cases of total hip and total knee infections from 1969 to 2004, Ritter said. He and his colleagues analyzed the infected joint patients vs. the non-infected patients to determine risk factors. The patient group included 4,974 men and 6,919 women with an average age of 68.1 years.
�There were 91 deep infections in the 17,000 [group] for a 0.52% infection rate,� Ritter said.
Ritter and his colleagues found no significant risk factors for deep infection alone. However, obesity was a statistically significant risk factor when the researchers analyzed the data for all aspects of infection, including deep infection and superficial infection, Ritter said. The infected patient group had an average 30.3�7.6 BMI and the uninfected group had an average 29.8�5.7 body mass index.
For more information:
- Ritter MA. Intraoperative controls for bacterial contamination during total knee replacement. Orthop Clin North Am. 1989;20(1):49-53.
- Ritter MA. Minimizing infection risk: Dodging the bullet. #32. Presented at the 7th Annual Current Concepts in Joint Replacement Spring 2006 Meeting. May 21-24, 2006. Las Vegas.