Microbiological Differences Among Age Groups in Patients Diagnosed With Periprosthetic Joint Infection: A Database Analysis of 2,392 Patients

Abstract

Introduction: Periprosthetic joint infection (PJI) after total joint arthroplasty (TJA) poses substantial economic and quality-of-life challenges. With the rising incidence of hip and knee arthritis globally, understanding the changing profile of PJIs across different age groups becomes crucial. While various studies have explored risk factors, the influence of age on PJI remains debated, with potential bimodal relationships. This study aims to investigate the causative organisms of PJIs in patients of different age groups undergoing TJA. Methods: Conducted as a retrospective cohort study at a high-volume PJI referral center, the study adhered to Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Data spanned from January 1, 2001, to December 31, 2022, including patients with documented PJI undergoing revision TJA. Patients were categorized into age quintiles, and outcomes analyzed included causative organisms, difficult-to-treat infections, antimicrobial resistance, and Gram stain characteristics. Statistical analyses used descriptive statistics, chi-square tests, and sensitivity analyses for hip and knee patients separately. Results: The study comprised 2,392 patients, with 60.7% undergoing hip arthroplasty and 39.3% undergoing knee arthroplasty. 1,080 women (45.2%) and 1,312 men (54.8%) were included. Older patients were markedly more likely to have gram-negative infections and atypical infections. Patients in the youngest age group had the lowest rates of methicillin-resistant Staphylococcus aureus infection. Results were similar between hip and knee PJIs. Conclusions: The study reveals age-related variations in the characteristics of PJIs after TJA, emphasizing higher risks of atypical and resistant infections in older patients. These findings underscore the importance of tailored preventive measures and potential considerations for adjunctive or prolonged antibiotic therapies, especially in the elderly population. Recognizing the unique infection patterns in older patients may inform better prevention and treatment strategies, with implications for enhanced patient care and outcomes. Future directions should focus on patient-specific strategies for preventing and treating PJIs, particularly in high-risk populations.