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Updated: Jun 12, 2025
Reverse Total Shoulder Arthroplasty
Published on: July 5, 2011
A functional evaluation of the rotator cuff length after reverse total shoulder arthroplasty
Jan Herregodts1, Mathijs Verhaeghe1,2, Didier Poncet3
1Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, Ghent, East-Flanders, Belgium.
Background:
A biomechanical result of the reverse total shoulder arthroplasty (rTSA) design is the medialization and inferiorization of the greater tuberosity, which influences the length of the cuff muscles. A well-known complication after rTSA is a lack of external rotation force. The purpose of this study was to investigate the difference in the length of the cuff muscles in a native shoulder and in shoulders treated with six commercial rTSA designs.
Methods:
Six implant systems were implanted on identical sawbones. A robotic setup was used to perform and control the shoulder's position and measurements. The muscle lengths were measured by draw wire encoders.
Results:
In the three functional positions, the length of the cuff muscles was significantly lower in the Delta Xtend. In all measured positions, there was a strong negative correlation between the medialization of the humerus and the length of the cuff muscles. A lower position of the humerus after rTSA had a positive impact on the length of the infraspinatus and subscapularis.
Discussion:
This study found a distinct difference in the slackening of the cuff muscles. Still, in the commercial reverse shoulder arthroplasty designs studied, this slackening never exceeded 15% in the above-mentioned maneuvers, which is functional and safe for the remnants of the muscles.
