Effect of Plane of Arm Elevation on Glenohumeral Kinematics A Normative Biplane Fluoroscopy Study
Understanding glenohumeral motion in normal and pathologic states requires the precise measurement of shoulder kinematics. The effect of the plane of arm elevation on glenohumeral translations and rotations remains largely unknown. The purpose of this study was to measure the three-dimensional glenohumeral translations and rotations during arm elevation in healthy subjects.
Eight male subjects performed scaption and forward flexion, and five subjects (three men and two women) performed abduction, inside a dynamic biplane fluoroscopy system. Bone geometries were extracted from computed tomography images and used to determine the three-dimensional position and orientation of the humerus and scapula in individual frames. Descriptive statistics were determined for glenohumeral joint rotations and translations, and linear regressions were performed to calculate the scapulohumeral rhythm ratio.
The scapulohumeral rhythm ratio was 2.0 ± 0.4:1 for abduction, 1.6 ± 0.5:1 for scaption, and 1.1 ± 0.3:1 for forward flexion, with the ratio for forward flexion being significantly lower than that for abduction (p = 0.002). Humeral head excursion was largest in abduction (5.1 ± 1.1 mm) and smallest in scaption (2.4 ± 0.6 mm) (p < 0.001). The direction of translation, as determined by the linear regression slope, was more inferior during abduction (-2.1 ± 1.8 mm/90°) compared with forward flexion (0.1 ± 10.9 mm/90°) (p = 0.024).
Scapulohumeral rhythm significantly decreased as the plane of arm elevation moved in an anterior arc from abduction to forward flexion. The amount of physiologic glenohumeral excursion varied significantly with the plane of elevation, was smallest for scaption, and showed inconsistent patterns across subjects with the exception of consistent inferior translation during abduction.
- SourceAvailable from: Mickael Begon
- "These exercises, by decreasing the ratio of deltoid to rotator cuff activation, could minimize upward translation (Blasier et al., 1997). Investigations that actually measured glenohumeral translations have shown that upward translation was smaller during scaption than during abduction when the arm is externally rotated (Giphart et al., 2013). However, to the best of our knowledge, no study assessed elevations with other axial rotations of the arm. "
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- "hinge, parallel mechanism, ball and socket as well as the segment length become another source of error (Duprey et al., 2010), which could lead to an increased joint kinematics error (Andersen et al., 2010). Double calibrations are efficient for quasi-planar movements in both lower (Stagni et al., 2009) and upper limb (Giphart et al., 2013), but has never been tested on daily living and sports activities. The latter are three-dimensional and may require multiple calibrations and a more complex correction model. "
ABSTRACT: Local and global optimization algorithms have been developed to estimate joint kinematics to reducing soft movement artifact (STA). Such algorithms can include weightings to account for different STA occur at each marker. The objective was to quantify the benefit of optimal weighting and determine if optimal marker weightings can improve humerus kinematics accuracy. A pin with five reflective markers was inserted into the humerus of four subjects. Seven markers were put on the skin of the arm. Subjects performed 38 different tasks including arm elevation, rotation, daily-living tasks, and sport activities. In each movement, mean and peak errors in skin- vs. pins-orientation were reported. Then, optimal marker weightings were found to best match skin- and pin-based orientation. Without weighting, the error of the arm orientation ranged from 1.9° to 17.9°. With weighting, 100% of the trials were improved and the average error was halved. The mid-arm markers weights were close to 0 for three subjects. Weights of a subject applied to the others for a given movement, and weights of a movement applied to others for a given subject did not systematically increased accuracy of arm orientation. Without weighting, a redundant set of marker and least square algorithm improved accuracy to estimate arm orientation compared to data of the literature using electromagnetic sensor. Weightings were subject- and movement-specific, which reinforces that STA are subject- and movement-specific. However, markers on the deltoid insertion and on lateral and medial epicondyles may be preferred if a limited number of markers is used. Copyright © 2015 Elsevier Ltd. All rights reserved.Journal of Biomechanics 04/2015; 48(10). DOI:10.1016/j.jbiomech.2015.03.023 · 2.75 Impact Factor
Annals of Physical and Rehabilitation Medicine 05/2014; 57:e113. DOI:10.1016/j.rehab.2014.03.391
- "However, it is not possible to insert sensors into the bones in clinical practice. Biplane fluoroscopy (Giphart et al., 2013) is another highly reliable technique but cannot be used in clinical practice either. Motion capture of the scapula using external sensors fixed over bony landmarks is subject to artefacts caused by skin sliding and muscle bulging (van Andel et al., 2009). "