Neonatal hip instability: normal values for physiological movement of the femoral head determined by an anterior-dynamic ultrasound method.
A total of 910 clinically normal hips in neonates younger than 48 h old was examined using an anterior-dynamic ultrasound method to determine normal values for the femoral head diameter and physiological movement of the femoral head in relation to the acetabulum. The femoral head diameters were found to correlate positively with both birthweight and gestational age and to be larger in boys than in girls, the mean values being 16.08 +/- 1.49 mm and 15.56 +/- 1.43, respectively. The values for maximal movement of the femoral head in relation to the acetabulum at provocation by Palmén/Barlow's test were 6.0, 6.6, and 6.8 mm for the birthweights 2,000, 3,000, and 4,000 g, respectively. No significant difference was found between the results of four independent observers in the femoral head movement at provocation. The results of the first and the fourth examination were not significantly different, suggesting that more than four examinations are required to induce hip instability by using the Palmén/Barlow test. Repeated examination after 4 h did not show any significant difference between examinations.
Department of Clinical Physiology, Norra Alvsborgs County Hospital, Trollhättan, Sweden.
J E
JE
Andersson
D005260:Female; D005270:Femur Head / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D006618:Hip Dislocation, Congenital / Q000175:diagnosis; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007231:Infant, Newborn; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D009068:Movement / Q000502:physiology; D015588:Observer Variation; D012016:Reference Values; D014463:Ultrasonography / Q000379:methods