Sonographic evaluation of hip effusion in children. Improved visualization with the hip in extension and abduction.
OBJECTIVE
To assess the difference in the sonographic appearance of hip effusions when the hip was placed in the extended and abducted position as compared to a neutral position.


METHODS
Twenty-one consecutive children (aged 2-14 years) with hip pain or limping were examined for hip effusions by means of ultrasound. The capsule-femoral-neck distance, the presence of joint fluid, and the shape of the anterior capsule were compared in hips in slight extension and abduction with those in hips in a neutral position.


RESULTS
Of the 11 positive hip effusions, the maximal distance between the capsule and femoral neck was significantly larger (p < 0.005) in the extended and abducted hip position than in the neutral hip position, with a mean difference of 1.6 mm. Convex bulging of the anterior capsule was more confidently diagnosed in 3 hip effusions in the extended and abducted hip, and better visualization of fluid between the capsule and femoral neck was achieved in 4 joint in this posture.


CONCLUSIONS
The study demonstrated an improvement in the sonographic detection of hip effusion in the extended and abducted position compared to the neutral position.
Chan
Y L
YL
Department of Diagnostic Radiology and Organ Imaging, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong.
Cheng
J C
JC
Metreweli
C
C
D000293:Adolescent; D018771:Arthralgia / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D005122:Exudates and Transudates / Q000000981:diagnostic imaging*; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006801:Humans; D007383:Intermittent Claudication / Q000000981:diagnostic imaging; D008297:Male; D016059:Range of Motion, Articular; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation