Journal article
Mechanical tradeoffs associated with glenosphere lateralization in reverse shoulder arthroplasty
Journal of shoulder and elbow surgery, Vol.24(11), pp.1774-1781
11/2015
DOI: 10.1016/j.jse.2015.06.011
PMID: 26238003
Abstract
Scapular notching in reverse shoulder arthroplasty occurs in up to 97% of patients. Notching is associated with decreased strength and reduced motion and may lead to long-term failure due to polyethylene wear. Many implant systems lateralize the glenosphere to address scapular notching, but the mechanical tradeoffs of lateralization have not been rigorously evaluated. We hypothesized that lateralization would decrease bony impingement but also decrease the mechanical advantage of the deltoid.
Finite element models were created using the same implants with different amounts of glenoid lateralization: 5 mm of medialization to replicate glenoid erosion, as well as 2.5, 5, 7.5, and 10 mm of lateralization. Tests were performed with static and dynamic scapulae for motion in either the coronal or scapular plane. The angle of impingement between the scapula and the humeral polyethylene was recorded, as was the deltoid force required to elevate the arm.
Increasing lateralization decreased impingement while increasing the deltoid force required to elevate the arm. Differences were found between the static and dynamic scapulae, with the dynamic scapula model having increased humeral adduction before impinging. The impingement angle was also substantially affected by the bony prominences on the inferior scapula, showing how individual bony anatomy can affect impingement.
Lateralization is effective in increasing impingement-free range of motion but also increases the deltoid force required to perform identical tasks. In addition, impingement is determined by scapular motion, which should be included in all shoulder models.
Details
- Title: Subtitle
- Mechanical tradeoffs associated with glenosphere lateralization in reverse shoulder arthroplasty
- Creators
- Carolyn M Hettrich - Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USA. Electronic address: carolyn-hettrich@uiowa.eduVijay N Permeswaran - Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USAJessica E Goetz - Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USADonald D Anderson - Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USA
- Resource Type
- Journal article
- Publication Details
- Journal of shoulder and elbow surgery, Vol.24(11), pp.1774-1781
- Publisher
- United States
- DOI
- 10.1016/j.jse.2015.06.011
- PMID
- 26238003
- ISSN
- 1058-2746
- eISSN
- 1532-6500
- Language
- English
- Date published
- 11/2015
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Orthopedics and Rehabilitation; Industrial and Systems Engineering
- Record Identifier
- 9984040237202771
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