medwireNews: Analysis of data for over 56,000 total knee arthroplasty (TKA) procedures has identified key risk factors for deep surgical site infection that could help guide the development of preventive strategies.
Patients were significantly more likely to experience infection if they were male (hazard ratio [HR]=1.89), had a body mass index (BMI) of at least 35 kg/m2 (hazard ratio [HR]=1.47), or had an American Society of Anesthesiologists score of 3 or above, indicating severe systemic disease (HR=1.65), after adjusting for a raft of confounding factors.
Deep surgical site infection was also significantly predicted in multivariate analysis by use of quadriceps-release exposure (HR=4.76), and antibiotic-laden cement (HR=1.53), as well as diagnoses of osteonecrosis (HR=3.65), post-traumatic arthritis (HR=3.23), or diabetes mellitus (HR=1.28), report Maria Inacio (Kaiser Permanente, San Diego, California, USA) and co-authors.
By contrast, patients were significantly less likely to develop the complication if they were Hispanic (HR=0.69 vs White patients), received antibiotic irrigation (HR=0.67), underwent bilateral TKA (HR=0.51), or attended a hospital with a low annual procedure volume (<100 vs ≥200 cases per year, HR=0.33).
The study, which included data from 56,216 TKAs performed at one of 45 US sites between 2001 and 2009, found no significant correlation between the risk for infection and patient age, diagnosis of rheumatoid arthritis, or use of laminar airflow or body exhaust suits in the operating room.
However, the likelihood of deep surgical site infection increased by a significant 9% for each additional 15-minute increase in operative time.
"As is the case for the observed increase in the risk of infection after total knee arthroplasties in which a quadriceps release or a tibial tubercle osteotomy was required, increased operative time is likely a proxy for the complexity of the surgical procedure," the researchers comment.
Inacio et al recommend that men should be counseled regarding their increased risk for deep surgical site infection, and believe that "optimization" of patient weight and diabetes control may significantly reduce infection rates.
"The use of antibiotic-laden cement in routine primary total knee arthroplasty is not supported by our findings, although the addition of antibiotics to irrigation fluid appears to reduce the risk of infection," they add.
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