The biomechanical effectiveness of tendon transfers to restore rotation after reverse shoulder arthroplasty: latissimus versus lower trapezius

2020 ◽  
pp. 175857322094625
Author(s):  
Kevin Chan ◽  
G Daniel G Langohr ◽  
George S Athwal ◽  
James A Johnson

Background The purpose of this biomechanical simulator study was primarily to compare latissimus dorsi to lower trapezius tendon transfers for active external rotation and the pectoralis major transfer for internal rotation after reverse shoulder arthroplasty. Secondarily, the role of humeral component lateralization on transfer function was assessed. Methods Eight rotator cuff deficient cadavers underwent reverse shoulder arthroplasty with an adjustable lateralization humeral component. Latissimus dorsi and lower trapezius transfers were compared for active external rotation restoration and pectoralis major transfer for internal rotation restoration. Internal rotation/external rotation torques were measured for each lateralization at varying abduction and internal rotation/external rotation ranges-of-motion. Results The lower trapezius transfer generated, on average, 1.6 ± 0.2 nm more torque than the latissimus dorsi transfer (p < 0.001). The internal rotation/external rotation torques of all tendon transfers decreased as abduction increased (p < 0.01). At 0° elevation, reverse shoulder arthroplasty humeral component lateralization had a significant positive effect on tendon transfer torque at 60° internal rotation and external rotation (p < 0.01). Discussion Both the lower trapezius and the latissimus dorsi tendon transfers were effective in restoring active external rotation after reverse shoulder arthroplasty; however, the lower trapezius generated significantly more torque. Additionally, the pectoralis major transfer was effective in restoring active internal rotation. All tendon transfers were optimized with greater humeral component lateralization.

2018 ◽  
Vol 100-B (9) ◽  
pp. 1182-1186 ◽  
Author(s):  
B. S. Werner ◽  
J. Chaoui ◽  
G. Walch

Aims Scapular notching is a frequently observed radiographic phenomenon in reverse shoulder arthroplasty (RSA), signifying impingement of components. The purposes of this study were to evaluate the effect of glenoid component size and glenosphere type on impingement-free range of movement (ROM) for extension and internal and external rotation in a virtual RSA model, and to determine the optimal configuration to reduce the incidence of friction-type scapular notching. Materials and Methods Preoperative CT scans obtained in 21 patients (three male, 18 female) with primary osteoarthritis were analyzed using modelling software. Two concurrent factors were tested for impingement-free ROM and translation of the centre of rotation: glenosphere diameter (36 mm vs 39 mm) and type (centred, 2 mm inferior eccentric offset, 10° inferior tilt). Results Glenosphere size was most predictive of increased extension and external rotation, whereas lateralization of the centre of rotation was the most predictive factor for internal rotation. A larger diameter of glenosphere combined with a 10° tilted configuration demonstrated superior values for extension and external rotation, whereas the eccentric component improved internal rotation by a mean 8.9° (standard deviation 2.7°) compared with a standard concentric glenosphere. Conclusion Glenosphere configuration can be modified to increase range of movement in RSA. Friction-type scapular notching was most effectively reduced by use of a large-diameter glenosphere with 10° inferior tilt. Cite this article: Bone Joint J 2018;100-B:1182–6.


2021 ◽  
pp. 175857322110671
Author(s):  
Garrett R Jackson ◽  
Joshua Meade ◽  
Bradley L Young ◽  
David P Trofa ◽  
Shadley C Schiffern ◽  
...  

Background Advances have been made to the traditional inlay Grammont Reverse Shoulder Arthroplasty (RSA) design such as the onlay humeral component prosthesis. Currently, there is no agreement in the literature regarding the best option for the humeral component when comparing inlay and onlay designs. This review compares the outcomes and complications between onlay versus inlay humeral components for RSA. Methods A literature search was conducted using PubMed and Embase. Only studies reporting outcomes comparing onlay versus inlay RSA humeral components were included. Results Four studies with 298 patients (306 shoulders) were included. Onlay humeral components were associated with better external rotation (ER) ( p < 0.0001). No significant difference in forward flexion (FF) or abduction was found. Constant scores (CS) and VAS scores did not differ. Increased scapular notching was found in the inlay group (23.18%) versus the onlay group (7.74%) ( p = 0.02). Postoperative scapular fractures and acromial fractures did not differ. Conclusion Onlay and inlay RSA designs are associated with improved postoperative range of motion (ROM). Onlay humeral designs may be associated with greater ER and lower rate of scapular notching; however, no difference was found in Constant and VAS scores, so further studies are required to assess the clinical significance of these differences.


2020 ◽  
pp. 175857322093623
Author(s):  
Georges Haidamous ◽  
Alexandre Lädermann ◽  
Robert U Hartzler ◽  
Bradford O Parsons ◽  
Evan S Lederman ◽  
...  

Background The purpose was to evaluate the relationship of component size and position to postoperative range of motion following reverse shoulder arthroplasty. The hypothesis was that increased lateralization, larger glenospheres, and a decreased acromiohumeral distance would be associated with excellent postoperative range of motion. Methods A retrospective multicenter study was performed at a minimum of one year postoperatively on 160 patients who underwent primary reverse shoulder arthroplasty with a 135° humeral component. Outcomes were stratified based on postoperative forward flexion and external rotation into excellent ( n = 42), defined as forward flexion >140° and external rotation > 30°, or poor ( n = 36), defined as forward flexion <100° and external rotation < 15°. Radiographic measurements and component features were compared between the two groups. Results A larger glenosphere size was associated with an excellent outcome ( p = 0.009). A 2-mm posterior offset humeral cup ( p = 0.012) and an increased inferior glenosphere overhang (3.1 mm vs 1.4 mm; p = 0.002) were also associated with excellent outcomes. Humeral lateralization and distalization were not associated with an excellent outcome. Conclusion: Larger glenosphere size and inferior positioning as well as posterior humeral offset are associated with improved postoperative range of motion following reverse shoulder arthroplasty. Level of Evidence Level 3, retrospective comparative study.


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