Ultrasound scapula tracking for the motion analysis of upper extremities

• Applicant: Dr.-Ing. Julien Leboucher, Ph.D.
• Subject Area: Orthopaedics, Traumatology, Reconstructive Surgery
• Term: from 2021 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 493517840

The scapula is the part of the shoulder complex with the most peculiar motion. It is articulated at the same time with the humerus, the clavicle and the posterior part of the thorax around the gleno-humeral (GH), acromio-clavicular (AC) and scapula-thoracic (ST) joints, respectively. This joint being subject of malfunction in a variety of conditions and strongly involved in a variety of activities of daily living (ADL), its study is of great importance.If cutaneous marker based methods are mostly used to estimate the motion of the scapula, estimated errors on attitude angles have been shown to be between 1° and 10°. The alternatives to cutaneous markers based methods include medical imaging, which can be costly and very difficult to apply for a routine, and the use of intracortical pins, which use is prevented by its invasiveness. In this study, we propose to apply a method based on ultrasound imaging, called freehand 3D ultrasound (3DUS), for tracking the scapula.Freehand 3DUS is non-radiating and cost effective that has been applied recently to in the field of human motion analysis (location of the humeral head center, the hip joint center, the femoral mediolateral axis or the attitude angles of the scapula). This method consists in tracking an object rigidly attached to an ultrasound probe in order to know the position of the probe and, thanks to a calibration procedure, of the image it yields.The primary objective of this study is to develop a method based on Freehand 3DUS that will aim at matching segmented contours from US images to a surface in order to estimate the location of the scapula during regular movement analyses performed with an optoelectronic motion capture system. The method’s applicability will then be assessed on both typically developed (TD) and cerebral palsied (CP) individuals. Results obtained on these two populations will be compared in order to evaluate the discriminating power of the method. State-of-the-art modeling methods will be applied to our results in order to determine if they are relevant in a clinical context or if a synthetic model should be developed.

• DFG Programme: WBP Position