Super Sterility at VCC
Medicare data indicates that the rate of prosthetic infection within the first 2 years of knee surgery is 1.55%. The infection rate in the next 2 to 10 years following surgery is an additional .46%. Therefore you can approximate your risk of infection after a TKR to be about 2 in 100. There are several risk factors that skew the overall infection rate and increase an individual’s risk of infection. These include, diabetes, rheumatoid arthritis, malnutrition, smoking, obesity, steroids, excessive anti-coagulation, chemotherapy, cancer, alcoholism, urinary tract infection, complex or revision surgery and multiple blood transfusions. In a study by Winiarsky et al, morbidly obese patients were compared to a control group of non-obese patients after TKR. A 225 rate of wound complications were found in the obese group, including 5 deep infections, as compared to a 2% rate of complications in the control group with .6% infections.
This information suggests that weight is a significant factor for infection and patients should be aware of the associated risk. Nutritional status may be a risk factor, particularly in the obese patient. Serum transferrin levels < 200mg/dL, an albumin level < .35 g/dL or a total lymphocyte count < 1500 cells/mm could be of concern for malnutrition and warrant a work up by your primary care doctor. Counseling by a nutritionist can be very helpful. Bariatric surgery may be an option that the obese patient can pursue. Staph is the most common type of knee infection, which includes Staph Aureus, Staph Epi, and methicillin resistant Staph Aureus or MRSA.
Although all are serious, the most difficult may be the MRSA variety. Fortunately, hospitals have been taking great efforts to control MRSA, which is often hospital-acquired. The rates of MRSA are decreasing in many hospital facilities, although the rate of community-acquired MRSA is increasing.