The potential of [¹⁸F]FDG PET/MRI for identifying pain sources in patients with diagnostically challenging chronic hip pain after total hip replacement.

Abstract

Chronic hip pain after total hip replacement (THR) poses a diagnostic challenge and frequently yields lengthy and unsatisfactory diagnostic work-up. This study aims to evaluate the diagnostic role and clinical impact of [¹⁸F]FDG PET/MRI compared with regular diagnostic work-up in patients with chronic hip pain after THR. In this randomized study, 20 patients with persistent hip pain of unclear origin after THR underwent either PET/MRI-guided clinical management or regular diagnostic work-up. Additional diagnostic and therapeutic procedures during 12-month follow-up were recorded and a final expert diagnosis was determined through expert opinion based on all available information. Patient reported outcomes included pain scores, functional scores and quality of life. In the PET/MRI group, a final expert diagnosis could be established for 8/10 patients compared to 5/10 in the control group. PET-MRI contributed to this diagnosis in 7 of 10 patients by identifying 5 new pain sources, confirming 3 clinically suspected pain sources, and excluding 1 clinically suspected pain source. At 6 months, mean pain scores on NRS 0-10 decreased in both groups (PET/MRI: 6.1 to 5.2; control: 5.2 to 3.4). Between-group differences could not be statistically tested due to insufficient statistical power. Initial results demonstrate the potential of [¹⁸F]FDG PET/MRI for the identification of pain sources in patients with diagnostically challenging chronic hip pain after THR. Further research regarding clinical outcome is warranted in a larger cohort with standardized treatment strategies incorporating PET/MRI findings.