Glenohumeral contact forces

Anglin, Carolyn; Wyss, Urs P.; Pichora, David R.

doi:10.1243/0954411001535660

Cited by 86 publications

(58 citation statements)

References 25 publications

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“…Muscular forces as well as total contact forces calculated with the model were low compared to values found in the literature [4,6,7,33]. The difference may be explained by the different motions considered.…”

Section: Discussioncontrasting

confidence: 59%

A finite element model of the shoulder: application to the comparison of normal and osteoarthritic joints

Büchler

Ramaniraka

Rakotomanana

et al. 2002

Clinical Biomechanics

138

101

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Objective. The objective of the present study was to develop a numerical model of the shoulder able to quantify the influence of the shape of the humeral head on the stress distribution in the scapula. The subsequent objective was to apply the model to the comparison of the biomechanics of a normal shoulder (free of pathologies) and an osteoarthritic shoulder presenting primary degenerative disease that changes its bone shape.Design. Since the stability of the glenohumeral joint is mainly provided by soft tissues, the model includes the major rotator cuff muscles in addition to the bones.Background. No existing numerical model of the shoulder is able to determine the modification of the stress distribution in the scapula due to a change of the shape of the humeral head or to a modification of the glenoid contact shape and orientation.Methods. The finite element method was used. The model includes the three-dimensional computed tomography-reconstructed bone geometry and three-dimensional rotator cuff muscles. Large sliding contacts between the reconstructed muscles and the bone surfaces, which provide the joint stability, were considered. A non-homogenous constitutive law was used for the bone as well as non-linear hyperelastic laws for the muscles and for the cartilage. Muscles were considered as passive structures. Internal and external rotations of the shoulders were achieved by a displacement of the muscle active during the specific rotation (subscapularis for internal and infrapinatus for external rotation).Results. The numerical model proposed is able to describe the biomechanics of the shoulder during rotations. The comparison of normal vs. osteoarthritic joints showed a posterior subluxation of the humeral head during external rotation for the osteoarthritic shoulder but no subluxation for the normal shoulder. This leads to important von Mises stress in the posterior part of the glenoid region of the pathologic shoulder while the stress distribution in the normal shoulder is fairly homogeneous.Conclusion. This study shows that the posterior subluxation observed in clinical situations for osteoarthritic shoulders may also be cause by the altered geometry of the pathological shoulder and not only by a rigidification of the subscapularis muscle as often postulated. This result is only possible with a model including the soft tissues provided stability of the shoulder. RelevanceOne possible cause of the glenoid loosening is the eccentric loading of the glenoid component due to the translation of the humeral head. The proposed model would be a useful tool for designing new shapes for a humeral head prosthesis that optimizes the glenoid loading, the bone stress around the implant, and the bone/implant micromotions in a way that limits the risks of loosening.

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Section: Discussioncontrasting

confidence: 59%

A finite element model of the shoulder: application to the comparison of normal and osteoarthritic joints

Büchler

Ramaniraka

Rakotomanana

et al. 2002

Clinical Biomechanics

138

101

View full text Add to dashboard Cite

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“…This confirms that the posterior area is loaded more intensely than the anterior or central regions. All these results concur with the regional variations reported for the material properties, such as bone density or strength [27][28][29][30], and the mechanical characteristics, such as loading conditions on the glenoid [34,13,22]. This suggests that an analysis of the morphological and mechanical characteristics of the trabecular bone would help to predict the predominant loading placed on the glenoid.…”

Section: Discussionsupporting

confidence: 86%

Mapping of the morphological and the material characteristics on the glenoid and estimation of predominant loading condition on the glenoid through the mapping

Lim

Kim

et al. 2009

J Mech Sci Technol

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The aim of this study was to predict and map the regional distribution of the trabecular architecture and the material properties of the glenoid and to estimate the predominant loading condition on the glenoid through the mapping. The morphological and material characteristics of the glenoid were investigated by analyzing digitized trabecular bone images obtained from twelve cadaver scapula specimens. The morphological and material characteristics computed from the cadaver specimens show that the predominant loading on the glenoid generally occurs during shoulder movement, which produces forces directed toward the posterior aspect of the bare region. This study is innovative in its detailed mapping of the morphological and material characteristics of the glenoid and its pioneering approach used to estimate the loading pattern acting on the glenoid through the mapping.

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“…Results from additional models indicated that this material behavior did not affect joint kinematics. A compressive 1-kN load is in the in the upper bound of expected glenoid loading, 35 and so was used in all analyses of constraint and conformity. The magnitude of shear loading required to induce joint instability was calculated for each of the seven constraints (Fig.…”

Section: Constraintmentioning

confidence: 99%

Glenohumeral kinematics following total shoulder arthroplasty: A finite element investigation

Hopkins

Hansen

Amis

et al. 2006

Journal Orthopaedic Research

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ABSTRACT:The osseous geometry of the glenohumeral joint is naturally nonconforming and minimally constrained, and the joint's stability is maintained by action of the rotator cuff muscles. Damage to these muscles is often associated with joint degeneration, and a variety of glenoid prostheses have been developed to impart varying degrees of stability postoperatively. The issues of conformity and constraint within the artificial shoulder have been addressed through in vivo and in vitro studies, although few computational models have been presented. The current investigation presents the results of three-dimensional finite element analyses of the total shoulder joint and the effects of design parameters upon glenohumeral interaction. Conformity was shown not to influence the loads required to destabilize the joint, although it was the principal factor determining the magnitude of humeral head translation. Constraint was found to correlate linearly with the forces required to dislocate the humeral head, with higher constraint leading to slightly greater humeral migration at the point of joint instability. The model predicts that patients with a dysfunctional supraspinatus would experience frequent eccentric loading of the glenoid, especially in the superior direction, which would likely lead to increased fixation stresses, and hence, a greater chance of loosening. For candidates with an intact rotator cuff, the models developed in this study predict that angular constraints of at least 148 and 6.58 in the superoinferior and anteroposterior axes are required to provide stable unloaded abduction of the humerus, with larger constraints of 188 and 108 necessitated by a dysfunctional supraspinatus. The tools developed during this study can be used to determine the capacity for different implant designs to provide resistance to excessive glenohumeral translations and reduce the potential for instability of the joint, allowing surgeons to optimize postoperative functional gains on a patient by patient basis. ß

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Glenohumeral contact forces

Cited by 86 publications

References 25 publications

A finite element model of the shoulder: application to the comparison of normal and osteoarthritic joints

A finite element model of the shoulder: application to the comparison of normal and osteoarthritic joints

Mapping of the morphological and the material characteristics on the glenoid and estimation of predominant loading condition on the glenoid through the mapping

Glenohumeral kinematics following total shoulder arthroplasty: A finite element investigation

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