Diagnostic Accuracy of Image-Guided Hip Joint Aspirations and Analysis of Predictive Parameters

Abstract

Caleb Bhatnagar, Andrew Pasion, Elizabeth Sager, Mathew Illimoottil, Stanley Chu and Emad Allam*

This study compares how well the findings from image-guided hip joint aspirations match those from subsequent surgery and investigates the factors that may explain any differences. We reviewed hip aspirations done from September 2014 to January 2023. Patients who had hip surgery within six months after aspiration were included, except those with incomplete records. We looked at differences in culture results and fluid samples between radiological and surgical procedures. Out of 94 hip aspirations, 63% were patients who had prior hip replacements. We found discrepancies in culture results in 17% of cases. In 69% of these, hip aspiration samples showed no bacterial growth, while surgery samples found growth. Delays in processing the samples correlated with these discrepancies (p=0.0166). P. acnes showed a significant tendency for discrepancies (p=0.0001). Differences in fluid acquisition occurred in 41% of cases, but lavage improved culture sensitivity by 80%. Overall, there are notable differences between image-guided hip aspirations and surgical findings. To improve results, lavage should be performed when there is no spontaneous aspiration of fluid, samples should be processed expeditiously, and special cultures should be used for fastidious organisms.