scholarly journals Reverse total shoulder arthroplasty: research models

Joints ◽  
2016 ◽  
Vol 04 (04) ◽  
pp. 236-246
Author(s):  
Stefano Petrillo ◽  
Umile Longo ◽  
Lawrence Gulotta ◽  
Alessandra Berton ◽  
Andreas Kontaxis ◽  
...  

Purpose:the past decade has seen a considerable increase in the use of research models to study reverse total shoulder arthroplasty (RTSA). Nevertheless, none of these models has been shown to completely reflect real in vivo conditions. Methods: we performed a systematic review of the literature matching the following key words: “reverse total shoulder arthroplasty” or “reverse total shoulder replacement” or “reverse total shoulder prosthesis” and “research models” or “biomechanical models” or “physical simulators” or “virtual simulators”. The following databases were screened: Medline, Google Scholar, EMBASE, CINAHIL and Ovid. We identified and included all articles reporting research models of any kind, such as physical or virtual simulators, in which RTSA and the glenohumeral joint were reproduced. Results: computer models and cadaveric models are the most commonly used, and they were shown to be reliable in simulating in vivo conditions. Bone substitute models have been used in a few studies.Mechanical testing machines provided useful information on stability factors in RTSA. Conclusions: because of the limitations of each individual model, additional research is required to develop a research model of RTSA that may reduce the limitations of those presently available, and increase the reproducibility of this technique in the clinical setting.

2021 ◽  
pp. 175857322110329
Author(s):  
Therese E Parr ◽  
Jennifer K Anderson ◽  
Alan M. Marionneaux ◽  
John M Tokish ◽  
Stefan J Tolan ◽  
...  

Background In a reverse total shoulder arthroplasty, the altered glenohumeral joint center of rotation subjects the glenoid baseplate to increased shear forces and potential loosening. Methods This study examined glenoid baseplate micromotion and initial fixation strength with the application of direct shear force in a Sawbone model. The reverse total shoulder arthroplasty systems examined were the DJO Reverse® Shoulder Prosthesis, the Exactech Equinoxe® Reverse System, and the Tornier AequalisTM Reverse Shoulder Prosthesis. Specimens were cyclically tested with increasing shear loads until 150 µm of displacement between the implant and glenoid was achieved, and subsequently until failure, classified as either 1 cm of implant/glenoid displacement or fracture. Results The average load withstood for the 150 µm threshold for DJO, Tornier, and Exactech was 460 ± 88 N, 525 ± 100 N, and 585 ± 160 N, respectively. The average total load at device failure for DJO, Tornier, and Exactech was 980 ± 260 N, 1260 ± 120 N, and 1350 ± 230 N, respectively. Discussion The Exactech implant design trended toward requiring more load to induce micromotion at each threshold and to induce device failure, most commonly seen as inferior screw pull out. This study proposes design features that may enhance fixation and suggests little risk of initial micromotion or failure during initial post-operative recovery.


Author(s):  
Madeleine L. Van de Kleut ◽  
Chaithanya Nair ◽  
Jaques S. Milner ◽  
David W. Holdsworth ◽  
George S. Athwal ◽  
...  

Author(s):  
Heath B. Henninger ◽  
Robert T. Burks ◽  
Robert Z. Tashjian

Reverse total shoulder arthroplasty (rTSA) provides significant pain relief and functional improvement in patients with a deficient rotator cuff, 4-part proximal humerus fracture, inflammatory arthritis or revision arthroplasty.[1, 2] As a non-anatomic procedure, rTSA transposes the ball and socket in the glenohumeral joint, allowing the deltoid to initiate elevation of the arm, provide stability and minimize shear forces acting at the glenoid surface.[3, 4]


2021 ◽  
Vol 24 (4) ◽  
pp. 272-278
Author(s):  
Young-Hoon Jo ◽  
Dong-Hong Kim ◽  
Bong Gun Lee

Anatomical total shoulder arthroplasty (TSA) has been used widely in treatment of glenohumeral osteoarthritis and provides excellent pain relief and functional results. Reverse total shoulder arthroplasty (RSA) was created to treat the complex problem of rotator cuff tear arthropathy. RSA also has been performed for glenohumeral osteoarthritis even in cases where the rotator cuff is preserved and has shown good results comparable with TSA. The indications for RSA are expanding to include tumors of the proximal humerus, revision of hemiarthroplasty to RSA, and revision of failed TSA to RSA. The purposes of this article were to describe comprehensively the conditions under which RSA should be considered in glenohumeral osteoarthritis, to explain its theoretical background, and to review the literature.


2020 ◽  
Vol 28 (2) ◽  
pp. 230949902092197
Author(s):  
Eugene Kim ◽  
Taedong Jang ◽  
Hee Jin Park ◽  
Sumika Ikemoto ◽  
Tsuyoshi Murase ◽  
...  

Background: In vivo three-dimensional (3D) kinematics of the scapula after reverse total shoulder arthroplasty (rTSA) have been sparsely investigated. The aim of this study was to analyze static and dynamic kinematic alterations of the scapula after rTSA in vivo with the use of computer-aided 3D reconstruction program. Methods: A total of 15 patients with cuff tear arthropathy treated by rTSA participated. Scapulae with rTSA and the contralateral scapulae were evaluated with computed tomography scan data in 0° and 120° forward flexion positions of the glenohumeral joint. To examine static scapular kinematic alterations, the angular position and distance from the thorax were evaluated in the shoulder neutral position. 3D rotational and translational movements of the scapula in relation to the thorax were also measured during arm elevation to evaluate dynamic scapular kinematic alterations. Results: Scapulae with rTSA were more anteriorly tilted in the sagittal plane and more internally rotated in the axial plane than were the contralateral scapulae. However, no significant differences were observed in the upward rotated position in the coronal plane or in the distance from the thorax in any plane between the scapulae with rTSA and the contralateral scapulae. In dynamic analyses, upward rotational movement in the coronal plane, external rotation in the axial plane, and posterior tilting in the sagittal plane showed significant differences between the scapulae with rTSA and the contralateral scapulae during elevation. In contrast, translational movements in coordination revealed no statistical differences between the two scapular groups except for lateral translation. Conclusion: Data from the 3D reconstruction program showed that rTSA might result in static positional changes and dynamic movement alterations. Level of Evidence: Therapeutic, IV


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