Impact of Temperature and Humidity on Periprosthetic Joint Infections Following Total Knee Arthroplasty: A 12-Year Study in a Mediterranean Climate

Purpose: This study aimed to examine the influence of temperature, humidity, and seasonal trends on periprosthetic joint infections (PJI) following total knee arthroplasty (TKA) over a 12-year period in a Mediterranean climate. Methods: A retrospective cohort study was conducted on 5520 patients who underwent TKA between January 1, 2011, and December 31, 2022. Data were collected on patient demographics, surgical details, and PJI incidence, which were defined by Musculoskeletal Infection Society (MSIS) criteria. Meteorological data on daily average temperature and relative humidity were obtained for the same period. Statistical analyses were performed to assess the associations between PJI incidence, seasonal variations, temperature, and humidity. Results: The overall incidence of PJI was 1.4%, with a significant downward trend over the 12 years (β coefficient= -0.115; p = 0.011). The highest PJI incidence (2%) was observed in winter, but no significant association was found between PJI incidence and seasonal variations (p = 0.080). The temperature range ≤5°C had the highest PJI rate (6.7%), while the 20-25°C range showed the lowest rate (0.4%). No significant effect of humidity levels on PJI incidence was identified (p=0.174). Conclusion: The study demonstrates a general decline in PJI incidence over time and suggests that colder temperatures are associated with higher PJI rates, with ≤5°C posing the most significant risk. However, humidity and seasonal variations did not significantly influence infection rates. These findings underscore the importance of considering environmental factors like temperature when planning TKA procedures, particularly in regions with Mediterranean climates. Level of evidence: Level III, Retrospective cohort study