2021 Undergraduate Research Showcase


Hip Mechanics of Infants: Understanding Hip Angles of an Infant in Different Baby Carrier Styles

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Student Presentation


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Faculty Sponsor

Dr. Erin Mannen


Infant position in baby carriers can affect their hip development and health. The Pavlik Harness is a device used to treat Developmental Dysplasia of the Hip (DDH) and is the standard for the healthy hip position of 90° flexion and 80° abduction angles. Standardized baby carrier styles that promote healthy hip position have not yet been established. The purpose of this study was to develop testing methods to accurately measure infant hip angles in various baby carriers. Three baby carriers under four conditions were placed on an adult manikin. One manikin representing a newborn which weighed approximately 2.83 kilograms was placed under the four conditions. The hip flexion and abduction angles were measured using a goniometer. The flexion angles were calculated through a MATLAB photo analysis function. The maximum force, peak pressure, and mean pressure that the carrier exerted onto the infant were measured during the first trial using two Novel pressure sensors. The sensors were placed around one thigh and the back and gluteus maximus. The Novel data was inconsistent and unreliable to measure forces exerted on the infant. Carrier B’s data resulted in the most similar hip position to the Pavlik Harness positioning. Carrier C’s data proved that it does not support the infant’s hips for healthy positioning. 75% of the photo analysis method resulted in smaller flexion angles compared to the measured angles using the goniometer. Labeling the anatomical landmarks for the photo analysis method was accessible and consistent. It was difficult to measure angles with the goniometer due to its shape and the positioning of the infant in the baby carrier. This preliminary data collection will lead to more advanced and detailed research with human subjects. A possible method for measuring hip flexion and abduction more accurately is to imbed a digital goniometer into the infant manikin or use a marker-based motion capture system like VICON. A standard for new baby carrier designs will be created when the optimal baby carrier style for hip position is identified.

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