Periprosthetic Hip Infections: the possible role of ultrasonography.

Background: Periprosthetic joint infections (PJI) of the hip represent a severe and debilitating complication following hip arthroplasty, associated with significant morbidity and healthcare costs. The early diagnosis of PJI is challenging due to its nonspecific clinical signs and symptoms, often overlapping with non-infectious conditions.

Methods: Our study was conducted on 30 patients with periprosthetic hip infections to analyze specific ultrasonographic patterns. Ultrasound examinations were performed by experienced sonographers, blinded to patient clinical and laboratory data. The assessment included joint effusion, periprosthetic fluid collections, synovial thickening, fistulous tracts, and hyperemia using Doppler imaging, correlated with laboratory markers, such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), D-dimer and white blood cell count (WBC).

Results: The most frequently observed ultrasonographic patterns associated with PJI were intra- and peri-articular tracts (80%), and joint effusion (73.33%), with supra-fascial effusion (60%) and sub-fascial effusion (56.67%). Doppler ultrasound revealed prosthetic hyperemia in 50% of patients and tissue hyperemia in 20%. Elevated CRP and ESR levels were present in 80% and 93.33% of patients, respectively. Indicative WBC count were found on the entirety of the examined sample and indicative D-dimer levels were present in 83.33% of patients.

Conclusions: Ultrasonography, enhanced by Doppler imaging, is a valuable diagnostic modality for assessing periprosthetic joint infections of the hip. The presence of intra- and peri-articular tracts and joint effusion were the most consistent findings. Integrating ultra-sonographic findings with laboratory tests is crucial for the accurate and timely diagnosis of PJI, and further multicenter studies are required to standardize its use and improve its clinical applicability.