Scapular kinematic reconstruction – segmental optimization, multibody optimization with open-loop or closed-loop chains: which one should be preferred?

Benjamin Michaud,Sonia Duprey,Mickaël Begon

doi:10.1080/23335432.2017.1405741

Abstract

Several numerical approaches have been developed to address the soft tissue artefact, such as the segmental optimization and multibody kinematics optimizations using either open-loop or closed-loop chains. However, it is still not clear which method is the most efficient for scapular kinematics reconstruction. In this study, six kinematic models were compared to a silver standard, i.e. a scapula palpator, during a series of 55 postures with maximal amplitudes of both the arm and scapula performed by 15 subjects. The most accurate approaches were the multibody optimization with a closed-loop chain and the segmental optimization. They provided averaged scapula misorientations of 14.9 ± 6.7° and 16 ± 7.1, respectively. Regarding the closed-loop chain integrating a point-to-ellipsoid scapulothoracic joint, the ellipsoid providing the most accurate results was a thorax-size ellipsoid fitting the area browsed by the scapula. Eventually, considering the high implementation costs of a multibody kinematics optimization, the segmental optimization could be considered as appropriate for scapular kinematics reconstruction.

Highlights

The scapulohumeral rhythm – i.e. the kinematic interaction between the scapula and the humerus – can be associated with diverse shoulder conditions (Kibler 2003) and can be used as an indicator of shoulder disabilities
Most of the studies focusing on scapula kinematics investigate classic humeral elevation motions (Lempereur et al 2014), while scapula range-ofmotion may be larger during sport or daily-living activities
All the approaches were mostly significantly different from all the others (Figure 3) except for the 6-DOF vs. ScapThoEllips and the NoEllips vs. ScapLungEllips approaches at low arm elevations; and the 6-DoF vs. NoEllips as well as the 6-DoF vs. ScapLungEllips approaches at high elevations (p > 0.05)

Summary

Introduction

The scapulohumeral rhythm – i.e. the kinematic interaction between the scapula and the humerus – can be associated with diverse shoulder conditions (Kibler 2003) and can be used as an indicator of shoulder disabilities. To calculate the scapulohumeral rhythm, both the scapular and the humeral kinematics must be acquired. The scapular kinematics is not trivial to measure. The large amount of muscles covering the scapula and the sliding movements of this bone under the skin can generate artefact up to 90 mm (Matsui et al 2006). Most of the studies focusing on scapula kinematics investigate classic humeral elevation motions (i.e. flexion or abduction) (Lempereur et al 2014), while scapula range-ofmotion may be larger during sport or daily-living activities. To assess the reliability of a measurement method dedicated to scapula kinematics, tasks requiring large scapula amplitude could bring a more thorough insight

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Conclusion