Measurement considerations on examiner-dependent factors in the ultrasound assessment of developmental dysplasia of the hip.

Our findings show that the standardized plane defined by Graf's criteria allows notable inclinations of the transducer positions. Transducer inclinations show an impact on measurement results, which are clinically relevant. Those effects cannot be ruled out using Graf's ultrasound criteria alone. The examiner should pay attention to avoid transducer inclinations in the frontal plane and a combination of posterior and cranial inclination.