Standardized ultrasound assessment with a classification system in greater trochanteric pain syndrome: a pilot study

Ultrasound (US) plays an important role in identifying the underlying cause of greater trochanteric pain syndrome (GTPS). However, establishing standardized US protocols and diagnostic criteria is essential for reproducible grading of GTPS severity. Such standardization would enhance radiological assessment, facilitating more informed treatment decisions by clinicians and patients. In this study, we performed standardized US examination and interpretation, and proposed a US classification system to better understand GTPS progression and severity.

In this prospective cross-sectional study, patients clinically diagnosed with GTPS between October 2023 and December 2024 were included and underwent standardized US examinations of the lateral hips. US findings of peritrochanteric bursitis, tendon abnormalities, calcification, increased vascularity, and bony alterations of greater trochanter (GT) were recorded and correlated with the visual analogue scale (VAS) score. Patients were classified into 1 of the 4 following categories: type I, isolated bursitis; type II, gluteal tendinosis with or without bursitis; type IIIA, gluteus tendon partial-thickness tear; and type IIIB, gluteus tendon full-thickness tear. Cohen's kappa coefficient was used to assess interobserver agreement of the US classification system.

Among the 55 hips with GTPS, US detected gluteus tendon abnormalities in 50 (90.9%) hips, peritrochanteric bursitis in 18 (32.7%), intratendinous calcification in 9 (16.4%), vascularity in 9 (16.4%), and bony abnormalities of GT in 40 (80%) hips. US findings of tendon abnormalities (P=0.002), tendon calcification (P<0.001), and tendon vascularity (P<0.001) predicted worse pain. There were 5 hips with type I, 44 hips with type II, and 6 hips with type III GTPS, and they had significantly increased VAS score (4.6±0.55 vs. 6.0±1.33 vs. 8.0±0.63, P<0.001). Interobserver agreement for the US classification system in assessment of GTPS was good [weighted k =0.77, 95% confidence interval (CI): 0.58-0.97, P<0.001].

Standardized US assessment with a classification system is a reliable tool to assess the severity of GTPS, and poses a potential to guide a more targeted treatment.