Anthropometric study of normal glenohumeral relationships

McPherson, Edward J.; Friedman, Richard J.; An, Yuehuei H.; Chokesi, Rakesh; Dooley, R. Larry

doi:10.1016/s1058-2746(97)90030-6

Cited by 133 publications

(99 citation statements)

References 20 publications

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“…The model was then scaled so as to set the radius of the humeral head to 24 mm, for future comparison purpose. The articular cartilage was reconstructed from general anatomical observations: an elliptical surface was fitted at the bony side (McPherson et al, 1997), while the articular side was represented by a spherical surface with a radius of 26 mm, which was positioned in such a way that the thickness in the middle was 2 mm (Soslowsky et al, 1992a). Muscles were modelled partly by 3D volumes and by cables (Fig.…”

Section: Methodsmentioning

confidence: 99%

Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction

Terrier

Reist

Vogel

et al. 2007

Clinical Biomechanics

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Background. Supraspinatus deficiency is the most frequent and important problem associated to rotator cuff pathologies. It reduces shoulder stability and can lead to osteoarthritis. The goal of this study was to develop a numerical model of the shoulder to analyse the biomechanical consequences of this pathology.Methods. A 3D finite element model of the shoulder was developed from a normal cadaver specimen. It included the scapula, the humerus and the major abduction muscles. Instead of the usual ball-socket assumption, which prevents the natural translation of the humerus, shoulder stability was actively achieved by muscles. A feedback algorithm was developed to synchronise muscle forces during abduction. The numerical algorithm was validated against an algebraic model, and the calculated muscle moment arms were compared to the literature. Two cases were considered: a normal shoulder and the same one without supraspinatus.Findings. For the normal shoulder, the model predicted the initial upward migration of the humeral head. The maximal humerus translation occurred at 30°of abduction and was 0.75 mm above its ideal centered position. Without supraspinatus, it was 1.6 times higher and the contact point in the glenoid fossa was more eccentric. For the normal shoulder, the maximal glenohumeral force was 81% of the body weight, at 82°of abduction. Without supraspinatus, it increased by 8%, while the increase of muscle forces was 30%.Interpretation. Supraspinatus deficiency increased the upward migration of the humerus, the eccentric loading, and the joint and muscle forces, which may cause a limitation of active abduction and degenerative glenohumeral changes (osteoarthritis and the rotator cuff tear).

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Section: Methodsmentioning

confidence: 99%

Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction

Terrier

Reist

Vogel

et al. 2007

Clinical Biomechanics

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“…The second circle, representing the articular side, was chosen to have a radius 2 mm greater than radius of the humeral head [6,7], and was positioned to set the cartilage thickness in the middle of the glenoid at 2 mm [6]. These two circles were then limited in the superior and inferior part by two radius lines, forming an angle of 66 degrees [16]. The deformation law of the cartilage layer was based on a Neo-Hookean potential w = 1.8(I 1 − 3), where I 1 is the first invariant of the right Cauchy-Green stress tensor [17].…”

Section: Methodsmentioning

confidence: 99%

An algorithm to allow humerus translation in the indeterminate problem of shoulder abduction

Terrier

Vogel

Capezzali

et al. 2008

Medical Engineering & Physics

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The shoulder is one of the most complex joints of the human body, mainly because of its large range of motion, but also because of its active muscular stabilisation. Actually, the numerous stabilizing muscles and degrees of freedom yield indeterminate biomechanical models. To solve this indeterminate, most models use reverse dynamics with a simplified ball-socket joint, preventing therefore the natural humerus translation. In this paper, an algorithm was specifically developed to solve the indeterminate problem by a feedback control of muscle activation, allowing the natural humerus translation. Abduction was considered in the scapular plane, accounting for the three deltoid parts and the rotator cuff muscles. The major aim of this study was to validate the numerical algorithm, which was here restricted to two-dimensions in order to compare the numerical solution to a known algebraic one. This comparison gave a relative error below 0.1%. The joint reaction force was comparable to other models and the humerus translation was in agreement with in vivo or in vitro studies.

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“…The anatomy of the proximal humerus can vary with respect to inclination, retrotorsion and the medial and dorsal offsets (the offset of the centre of rotation in relation to the humeral axis) [1,6,9,14,17,20,21]. Due to this, many groups call for this anatomy to be repaired as precisely as possible when implanting a humeral prosthesis in order to achieve optimal postoperative joint function [1,4,5,7,8,10,13,15,16,18,20,22,23].…”

Section: Introductionmentioning

confidence: 99%

Differences in reconstruction of the anatomy with modern adjustable compared to second-generation shoulder prosthesis

Irlenbusch

End

Kılıç

2010

International Orthopaedics (SICOT)

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Reconstruction of the anatomy of the proximal humerus is a prerequisite to achieving good long-term clinical results after shoulder arthroplasty. Modern, adjustable prostheses have greater flexibility of inclination, retroversion, and medial and dorsal offset in comparison with older prostheses. Such improvements should allow for better reconstruction of the centre of rotation compared to older prostheses. Reconstruction of the humeral head centre was assessed in 106 modern adjustable (Affinis) and 47 second-generation prostheses. All reconstructions were compared both to the preoperative state and the unoperated shoulder. To describe the pre-and postoperative states, the geometry and position of the humeral head in relation to the glenoid were analysed on patient radiographs. Applying the defined parameters, modern adjustable prostheses showed better reconstruction than second generation prostheses. Parameter values measured in reconstructions using fourth generation prostheses were comparable to those of the unoperated shoulder, but differed significantly from the preoperative state. Second generation prostheses, in contrast, only show non-specific differences in parameter values. This suggests that an approximate reconstruction of normal anatomy can be achieved using a modern fourth generation prosthesis. Reconstruction of the complex anatomy of the proximal humerus is significantly better with modern adjustable prostheses compared to second generation prostheses. Improved clinical outcome can therefore be predicted in a functional and intact rotator cuff. The advantage of using modern prostheses systems over older models is clearly demonstrated in this study. IntroductionThe anatomy of the proximal humerus can vary with respect to inclination, retrotorsion and the medial and dorsal offsets (the offset of the centre of rotation in relation to the humeral axis) [1,6,9,14,17,20,21]. Due to this, many groups call for this anatomy to be repaired as precisely as possible when implanting a humeral prosthesis in order to achieve optimal postoperative joint function [1,4,5,7,8,10,13,15,16,18,20,22,23]. Others go further and insist on reconstruction of the centre of rotation specifically [17].In many cases of osteoarthritis, flattening of the humeral head can be identified (Fig. 1a, b), resulting in conditional lateral displacement of the centre of rotation in relation to shaft axis but causing a medial shift of the of the rotational centre in relation to the glenoid. Other patients show a primary osteoarthritis with no significant deformation of the humeral head (Fig. 1c). The technical demands for reconstruction of the rotational centre differ considerably in both cases.Modern prostheses allow adaptation to both the primary and also pathologically altered secondary anatomy. These prostheses generally allow eccentric adjustment of the prosthesis head in relation to the shaft. Some also feature variable, adjustable inclination.In order to reconstruct a shoulder as closely as possible to the contralateral side...

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Anthropometric study of normal glenohumeral relationships

Cited by 133 publications

References 20 publications

Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction

Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction

An algorithm to allow humerus translation in the indeterminate problem of shoulder abduction

Differences in reconstruction of the anatomy with modern adjustable compared to second-generation shoulder prosthesis

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