Pre-operative Waterlow score: Predicts risk of post-operative infection in patients with neck of femur fractures.

INTRODUCTION

Nursing staff prospectively collect Waterlow scores (Ws) on all inpatients across most NHS hospitals, identifying patients at risk of pressure ulcers. This bedside score has not been applied in predicting other negative outcomes in patients with neck of femur (NOF) fractures.

OBJECTIVES

To investigate the relationship between increasing Waterlow score and 30-day post-operative infection in patients with NOF fracture.

PATIENTS AND METHODS

Pre-operative Ws and 30-day clinical outcome data were collected on 97 consecutive operatively treated NOF fracture patients at our institution (level one trauma centre).

RESULTS

30-day infection rate was 36%, which manifested as hospital acquired pneumonia (66%) and urinary tract infection (34%). For every one point increase in Ws, the odds of having an infection increased by 1.68 times (95% CI 1.37-2.08). The relationship between Ws and 30-day infection was similar when adjusted for potential confounders: patient demographics (age and gender), number of medical comorbidities, ASA grade, and days to surgery. For our data, the Ws predictive of infection was ≥17. This has a sensitivity of 84.9% (95% CI 68.1-94.9%) and a specificity of 84.1% (95% CI 74.7-92.1%). The area under the curve was 0.89 (95% CI 0.82-0.96).

CONCLUSION

Our study demonstrates a strong relationship between increasing Ws and post-operative infection risk. This raises the interesting yet controversial question of using Ws to identify patients at high-risk of developing post-operative infections and the potential benefit of an extended period of antibiotic prophylaxis.