LAUSR

Background Acute hip pain caused by femoral proximal fractures or acute hip arthritis requires imaging for accurate diagnosis. Although pocket-sized ultrasound (PsUS) offers several advantages over other imaging modalities, there is limited information regarding its use in diagnosing femoral proximal fractures or acute hip arthritis. Thus, we aimed to validate the diagnostic accuracy of PsUS for both disorders. Methods In this prospective observational study, outpatients with acute hip pain were diagnosed according to a fixed procedure of the PsUS probe handling. We verified the diagnostic accuracy of PsUS findings (cortical discontinuity and joint fluid retention) and compared it with that of radiography, computed tomography, and magnetic resonance imaging. Results Our study included 52 outpatients (mean age, 78.0 years; female, 88.5%). Of 26 patients diagnosed with femoral proximal fractures, 14 had femoral neck fractures and 12 had femoral trochanteric fractures. The sensitivity and specificity for identifying cortical discontinuity in femoral proximal fractures were 0.96 and 0.92, respectively. The sensitivity for identifying either cortical discontinuity or joint fluid retention in femoral proximal fractures or acute hip arthritis was 0.97. Conclusions Negative PsUS findings of cortical discontinuity and joint fluid retention in the hip are useful for ruling out femoral proximal fractures and acute hip arthritis. PsUS and radiography have comparable diagnostic accuracies, and PsUS could aid in the initial assessment of acute hip pain among the elderly in primary care settings.