Clinical Evaluation of an Electronic Guidance System for Optimizing the Ultrasound Screening for Developmental Hip...

Background: Graf ultrasound screening is considered an established method for early detection of developmental dysplasia of the hip (DDH). Although characterized by a high degree of standardization to allow for good reproducibility of results, examination-related factors may still affect sonographic measurements. The relative tilt angle between the hip and the probe is a potential pitfall as it significantly influences sonographic measurements and consequently classification of DDH according to Graf. Objectives: Evaluation of an electronic guidance system developed to reduce relative tilt angles and increase reliability and comparability in ultrasound screening of DDH. Materials and Methods: Twenty-five newborns were examined using a prototype guidance system, which tracks the position of the transducer and the pelvis to calculate the relative tilt angles. Two ultrasound images were obtained, one conventionally and the other one using the guidance system. Subsequently, relative roll and pitch angles and sonographic measurements were determined and analyzed. Results: The relative inclination angles in the conventional group ranged from -12.6° to 14.3° (frontal plane) and -23.8° to 32.5° (axial plane). vs. -3.7° to 3.0° and -3.2° to 4.5° in the guidance system group. The variances were significantly lower in the guidance system-assisted group for both planes (p < 0.001 and p < 0.001, respectively). The optimized transducer position showed significant effects and consequently significantly reduced alpha angles were observed (p = 0.001, and p = 0.003). Conclusions: The guidance system allowed a significant reduction in the relative tilt angles, supporting optimal positioning of the transducer, resulting in significant effects on Graf sonographic measurements. This technique shows great potential for enhancing the reproducibility and reliability of ultrasound screening for DDH.