A Retrospective Analysis on the Effect of Obesity and Rurality on Infection Burden After Joint Arthroplasty in a Rural Australian Population

Rory Maguire, Alexa Seal, Kerin Fielding

Background

Periprosthetic joint infection (PJI) is a potentially disastrous complication of shoulder, hip, and knee joint replacements, associated with significant increases in morbidity and mortality, and economic burden. Literature suggests that PJI mortality is associated with preoperative morbidity and the disease process rather than treatment. Rural populations often face distinct challenges in healthcare access, lifestyle, and socioeconomic factors, which may contribute to an increase in the prevalence of obesity as a risk factor for PJIs. While the association between patient risk factors and PJIs have been extensively studied globally, there is a notable gap in understanding these dynamics within regional populations, particularly in rural Australia.

Aim

This study aims to address the existing gap in the literature by conducting a comprehensive analysis of obesity and rurality as a risk factor to PJI in a rural NSW region. Specifically, this study will:

1. Investigate the risk of infection in obesity and categories of BMI according to the World Health Organisation (underweight (BMI <18.5), normal weight (BMI 18.5-24.9), pre-obese (BMI 25.0-29.9), Obesity class I (BMI 30-34.9), Obesity class II (BMI 35.0 –39.9), Obesity class III (BMI >40)) prior to joint arthroplasty.

2. Investigate the risk of infection in categories of rurality according to the Modified Monash (MM) model (MM1 – metropolitan areas; MM2 – regional areas; `MM3 – large rural towns; MM4 – medium rural towns; MM5 – small rural towns; MM6 – remote communities; MM7 – very remote communities).

Method

Data will be requested from the Australian Orthopaedic Associations National Joint Replacement Registry (AOA NJRR) to perform a retrospective analysis of PJIs associated with primary joint arthroplasties performed at Wagga Wagga Base Hospital and Calvary Hospital Wagga Wagga between 01 January 2015 and 31 January 2023. BMI data will be classified according to the WHO guidelines and postcode data will be classified according to the MM model.

Summary

This research seeks to provide valuable insights into the regional dynamics of PJIs, enabling the development of targeted preventative measures enhancing overall orthopaedic care in rural communities.

References

• 1. Projected Economic Burden of Periprosthetic Joint Infection of the Hip and Knee in the United States. Accessed January 31, 2024.https://pubmed.ncbi.nlm.nih.gov/33422392/
• 2. High Mortality After Total Knee Arthroplasty Periprosthetic Joint Infection is Related to Preoperative Morbidity and the Disease Process but Not Treatment. Accessed January 31, 2024. https://pubmed.ncbi.nlm.nih.gov/35314288/
• 3. Summers R, Lea J, East L. An exploration of extreme obesity and weight loss management for adults in rural, remote, and regional areas: a systematic review. Contemp Nurse. Published online January 22, 2024:1-13. doi:10.1080/10376178.2024.2304712