What are the risk factors and microorganism profiles of periprosthetic hip joint infections with a concomitant sinus tract?

Introduction: A sinus tract, an abnormal channel between the skin and joint, is a major criterion that proves the presence of an underlying periprosthetic joint infection. Its presence not only increases failure rates but also leads to poor outcomes. Despite its clinical relevance, little is known about risk factors and underlying microorganism profiles. The aim of this study was to investigate PJIs of the hip with a sinus tract, identifying risk factors and microorganism profiles.

Materials and methods: This was a retrospective case control study of all PJI cases of the hip treated at our institution. A total of 4,368 cases with a PJI of the hip were identified of which 653 patients (14.95%), displayed a sinus tract. Univariate and multivariate analysis was performed. Odds ratio (OR) and 95% confidence interval (CI) were presented.

Results: Multivariate analysis identified diabetes mellitus (p = 0.004; OR = 1.62; 95% CI 1.17-2.44), history of ileus (p < 0.001; OR = 4.65; 95% CI 2.38-9.08), osteomyelitis (p < 0.001; OR = 2.35; 95% CI 1.65-3.35) and prior revisions (p = 0-014; OR = 1.36; 95% CI 1.07-1.74) as risk factors for a sinus tract. Polymicrobial infections (p < 0.001; OR = 2.35; 95% CI 1.86-2.96), Staphylococcus aureus (p < 0.001; OR = 3.67; 95% CI 2.86-4.71) and Escherichia coli (p = 0.014; OR = 1.65; 95% CI 1.11-2.46) were associated with a sinus tract in PJIs of the hip.

Conclusions: Microorganism profiles and risk factors differ significantly in patients with PJI of a THA with a sinus tract. These insights can help surgeons in planning and selecting appropriate antibiotics for cement loading and empiric antibiotic treatment, as well as in risk stratification of patients, who may develop a sinus tract following THA.