Validity of US measurements of cam-type femoroacetabular impingement parameters: a preliminary study in an asymptomatic adult population.
PURPOSE
To determine the accuracy of US for the quantitative parameters of cam-type femoroacetabular impingement (FAI) in an asymptomatic adult population, using MRI as the reference standard.


MATERIALS AND METHODS
We prospectively evaluated 158 hips of 79 adult subjects (44 males, 35 females; age range 18-49 years) with a negative anterior impingement test. Two observers independently measured anterosuperior quadrant alpha angles and anterior femoral distances (AFDs) on both US and MRI.


RESULTS
US measurements of alpha angle and AFD had a moderate-to-high positive correlation with MRI measurements and there was substantial and/or almost perfect agreement between observers on both imaging modalities. Anterior femoral distance measurements for both observers and alpha angles at MRI for Observer 1 showed no statistically significant difference between genders.


CONCLUSION
Ultrasonography can be used for anterosuperior alpha angle and AFD measurements in asymptomatic adults. However, when used as the sole imaging method, its inherent limitations and possible discrepancies with MRI should be kept in mind.
['Balci|Sinan|S|http://orcid.org/0000-0002-1356-9795', 'Karanfil|Yigitcan|Y|', 'Oguz|Berna|B|', 'Aydingoz|Ustun|U|']
D000077:Acetabulum D000293:Adolescent D000328:Adult D005260:Female D057925:Femoracetabular Impingement D005269:Femur D006621:Hip Joint D006801:Humans D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D011446:Prospective Studies D015203:Reproducibility of Results D014463:Ultrasonography D055815:Young Adult
Femoroacetabular impingement Ultrasonography Magnetic resonance imaging