Effect of the Scapulo-Humeral Rhythm on Anatomical and Reverse Shoulder Prostheses

Details

Serval ID
serval:BIB_5CC027F7C182
Type
Inproceedings: an article in a conference proceedings.
Publication sub-type
Abstract (Abstract): shot summary in a article that contain essentials elements presented during a scientific conference, lecture or from a poster.
Collection
Publications
Institution
Title
Effect of the Scapulo-Humeral Rhythm on Anatomical and Reverse Shoulder Prostheses
Title of the conference
Annual meeting of the Swiss Society of Orthopaedics and Traumatology
Author(s)
Farron A., Aeberhart M., Pioletti D., Terrier A.
Address
St. Gallen - Switzerland, 30 June - 2 July 2010
ISBN
1424-7860
Publication state
Published
Issued date
2010
Peer-reviewed
Oui
Volume
140
Series
Swiss Medical Weekly
Pages
14S
Language
english
Notes
Meeting Abstract
Abstract
Introduction: Several studies have reported significant alteration of the scapula-humeral rythm after total shoulder arthroplasty. However, the biomechanical and clinical effects, particularly on implants lifespan, are still unknown. The goal of this study was to evaluate the biomechanical consequences of an altered scapula-humeral rhythm.
Methods: A numerical musculoskeletal model of the shoulder was used. The model included the scapula, the humerus and 6 scapulohumeral muscles: middle, anterior, and posterior deltoid, supraspinatus, subscapularis and infraspinatus combined with teres minor. Arm motion and joint stability were achieved by muscles. The reverse and anatomic Aequalis prostheses (Tornier Inc) were inserted. Two scapula-humeral rhythms were considered for each prosthesis: a normal 2:1 rhythm, and an altered 1:2 rhythm. For the 4 configurations, a movement of abduction in the scapular plane was simulated. The gleno-humeral force and contact pattern, but also the stress in the polyethylene and cement were evaluated.
Results: With the anatomical prosthesis, the gleno-humeral force increased of 23% for the altered rhythm, with a more eccentric (posterior and superior) contact. The contact pressure, polyethylene stress, and cement stress increased respectively by 20%, 48% and 64%. With the reverse prosthesis, the gleno-humeral force increased of
11% for an altered rhythm. There was nearly no effect on the contact pattern on the polyethylene component surface.
Conclusion: The present study showed that alteration oft the scapula-humeral rythm induced biomechanical consequences which could preclude the long term survival of the glenoid implant of anatomic prostheses. However,an altered scapula-humeral rhythm, even severe, should not be a contra indication for the use of a reverse prosthesis. 
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Create date
14/10/2010 11:34
Last modification date
20/08/2019 14:15
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