An interventional study of Lateralization of glenoid component and Standard implantation technique in Cuff Tear Arthropathy, Omarthrosis and Rotator Cuff Tear Arthropathy, sponsored by Vienna Hospital Association. Not yet recruiting at 1 site in Austria. Open to participants aged 60 Years to 85 Years. Per ClinicalTrials.gov, last updated 2026-05-07.
Sponsored by Vienna Hospital Association · Not applicable, Interventional, and Diagnostic
Reverse total shoulder arthroplasty (RTSA) is a well-established method to treat patients with irreparable rotator cuff tears and glenohumeral osteoarthritis. The biomechanical principle implies a medialization and distalization of the center of rotation (COR). Deficiencies in internal and external rotation constitute frequently encountered functional problems. Some studies showed reduced activation of the posterior deltoid in EMG measurements, which may explain the inability to compensate these movements. Lateralized prosthetic designs demonstrated increased external rotation through an alteration of the deltoid's lever arm.
The aim of the study is to investigate the impact of lateralization on functional outcome and deltoid EMG activity in comparison to a standard implantation technique.
Introduction Reverse total shoulder arthroplasty (RTSA) is a well-established method to treat patients with irreparable rotator cuff tears and glenohumeral osteoarthritis. The biomechanical principle is a medialization and distalization of the center of rotation (COR) to provide a compensatory role for the insufficient rotator cuff. Deficiencies in internal and external shoulder rotation constitute frequently seen functional problems. Some studies showed reduced activation of the posterior deltoid in EMG measurements, which may explain the inability to compensate these movements. Lateralized prosthetic designs implants demonstrated increased external rotation force through an alteration of the deltoid's lever arm.
Material and Methods This study will be conducted as a monocentric randomized, prospective trial. Approximately 130 patients, scheduled for reversed total shoulder arthroplasty (RSA), will be enrolled. The patients will be divided into two groups depending on receiving RSA or a lateralized implant via randomization. Preoperatively and at 4 follow-up visits, a surface EMG (sEMG) of the deltoid muscle will be conducted and clinical scores (Constant-Murley Score and Quick DASH questionnaire) will be assessed. As patient related outcome measures, p-ASES-S and SVV will be evaluated. Pre- and postoperative x-rays and CT scans will be conducted for preoperative planning and measurement of achieved lateralization. Clinical and radiological complications will be routinely documented. Group comparisons and correlations will be performed to compare both groups pre- and postoperatively. The study's duration is scheduled for 2 years.
Aim of the Study The aim of the study is to evaluate a possible difference in function and EMG activity between the two patient groups. Especially a different increase in external rotation range of motion and strength shall be investigated. Furthermore a possible connection between preoperative deltoid muscle activity and postoperative outcome shall be pointed out. Lastly, the impact of lateralization on functional outcome, shall be evaluated compared to the standard implantation technique.
57 studies on the registry are indexed under Rotator Cuff Tear Arthropathy; 15 are open to participants now.
This study's planned enrollment of 130 is above the median of 90 across 33 interventional studies indexed under Rotator Cuff Tear Arthropathy.
Browse Rotator Cuff Tear Arthropathy studies →Vienna Hospital Association is the lead sponsor of 11 studies on the registry; 7 are open to participants now.
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Exclusion Criteria:
Subjects treated with a standard glenoid component of the used reverse total shoulder prosthesis
Device: Standard implantation technique
Subjects treated with a lateralized glenoid component of the used reverse total shoulder prosthesis
Device: Lateralization of glenoid component
Lateralization of glenoid component in reverse total shoulder arthroplasty via metal augment on the glenoid side with a thickness of at least 4mm
Implantation of a standard glenoid component without any lateralization via metal back on the glenoid site
Delta Muscle activity (especially posterior Delta part)
The ratio between peak torque and EMG root mean square is measured
Time frame: preoperative
Delta Muscle activity (especially posterior Delta part)
The ratio between peak torque and EMG root mean square is measured
Time frame: 6 weeks postoperative
Delta Muscle activity (especially posterior Delta part)
The ratio between peak torque and EMG root mean square is measured
Time frame: 3 months postoperative
Delta Muscle activity (especially posterior Delta part)
The ratio between peak torque and EMG root mean square is measured
Time frame: 6 months postoperative
Delta Muscle activity (especially posterior Delta part)
The ratio between peak torque and EMG root mean square is measured
Time frame: 1 year postoperative
Range of movement (forward flexion, abduction, external rotation, extension)
ROM (range of movement) measured with a goniometer according to neutral zero method
Time frame: preoperative
Range of movement (forward flexion, abduction, external rotation, extension)
ROM (range of movement) measured with a goniometer according to neutral zero method
Time frame: 6 weeks postoperative
Range of movement (forward flexion, abduction, external rotation, extension)
ROM (range of movement) measured with a goniometer according to neutral zero method
Time frame: 3 months postoperative
Range of movement (forward flexion, abduction, external rotation, extension)
ROM (range of movement) measured with a goniometer according to neutral zero method
Time frame: 6 months postoperative
Range of movement (forward flexion, abduction, external rotation, extension)
ROM (range of movement) measured with a goniometer according to neutral zero method
Time frame: 1 year postoperative
Objective and subjective outcome scores / Quality of life scores
Constant score (0-100) (higher = better)
Time frame: preoperative, 6 weeks postoperative, 3 months postoperative, 6 months postoperative, 12 months postoperative
Objective and subjective outcome scores / Quality of life scores
SVV (subjective shoulder value) (0-100%) (higher = better)
Time frame: preoperative, 6 weeks postoperative, 3 months postoperative, 6 months postoperative, 12 months postoperative
Objective and subjective outcome scores / Quality of life scores
p-ASES (patient-reported American Shoulder and Elbow Surgeons Score) (0-100) (higher = better)
Time frame: preoperative, 6 weeks postoperative, 3 months postoperative, 6 months postoperative, 12 months postoperative
Objective and subjective outcome scores / Quality of life scores
Quick-DASH (Quick-Disability of Arm, Shoulder and Hand) (0-100) (higher = better)
Time frame: preoperative, 6 weeks postoperative, 3 months postoperative, 6 months postoperative, 12 months postoperative
Difference in lateralization between preoperative 3D CT-based planning and postoperative CT-based implant position
Lateralization will be quantitatively assessed by comparing preoperative and postoperative computed tomography (CT) scans. The preoperative CT scan will be used for 3D planning and virtual implantation. The postoperative CT scan will be used to determine the actually achieved implant position. The original preoperative joint line will serve as the reference value. Medialization or lateralization will be measured as the linear distance (in millimeters) between the preoperative joint line and the postoperative implant position. The achieved lateralization will be calculated based on this difference. Additionally, the planned lateralization from the preoperative 3D virtual implantation will be compared with the actually achieved lateralization measured on the postoperative CT scan. The primary metric will be the absolute and mean deviation (in millimeters) between planned and achieved lateralization, allowing assessment of the accuracy of the preoperative 3D planning.
Time frame: Preoperative and 1 year postoperative
Humeral Length (Millimeters) Measured on Standardized Radiographs
Humeral length will be measured in millimeters on standardized anteroposterior radiographs of the entire humerus obtained according to the Lädermann protocol. Measurements will be performed by comparing preoperative and postoperative radiographs. The primary metric will be the absolute difference in humeral length between preoperative and postoperative images. Measurements will be performed using calibrated digital imaging software by blinded reviewers.
Time frame: preoperative, 6 weeks postoperative, 3 months postoperative, 6 months postoperative, 12 months postoperative
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Start is estimated for Jun 2026; primary completion for Aug 2027, 14 months later.
Of 20 interventional studies with no phase under Rotator Cuff Tear Arthropathy, half reached primary completion within 69 months of starting (the median), counting those still running; a quarter within 45 and three quarters within 72. This study's planned 14 months is below that.
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This study is not yet recruiting, as verified in May 2026. You cannot join it, but the record below documents what was studied.
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