Cuff Tear Arthropathy, Omarthrosis, Rotator Cuff Tear Arthropathy
Conditions
Keywords
reverse total shoulder arthroplasty, cuff tear arthropathy, lateralization, deltoid function, EMG
Brief summary
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.
Detailed description
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.
Interventions
DEVICELateralization 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
DEVICEStandard implantation technique
Implantation of a standard glenoid component without any lateralization via metal back on the glenoid site
Sponsors
Vienna Hospital Association
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
DIAGNOSTIC
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
60 Years to 85 Years
Healthy volunteers
No
Inclusion criteria
* male/female, 60-85y * diagnosis of Cuff tear arthropathy (CTA) * irreparable rotator cuff tear * severe osteoarthritis (OA) * primary RSA * verified rotator cuff tear in preoperative MRI * absence of severe cognitive impairment
Exclusion criteria
* previous muscle transfer * revision surgery * highly dysplastic glenoid * axillary nerve palsy * upper limb radiculopathy * cervical myelopathy * degenerative muscular disease, * previous proximal humeral fracture * revision arthroplasty * rheumatoid arthritis
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Delta Muscle activity (especially posterior Delta part) | preoperative | The ratio between peak torque and EMG root mean square is measured |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Range of movement (forward flexion, abduction, external rotation, extension) | preoperative | ROM (range of movement) measured with a goniometer according to neutral zero method |
| Objective and subjective outcome scores / Quality of life scores | preoperative, 6 weeks postoperative, 3 months postoperative, 6 months postoperative, 12 months postoperative | Constant score (0-100) (higher = better) |
| Difference in lateralization between preoperative 3D CT-based planning and postoperative CT-based implant position | Preoperative and 1 year postoperative | 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. |
| Humeral Length (Millimeters) Measured on Standardized Radiographs | preoperative, 6 weeks postoperative, 3 months postoperative, 6 months postoperative, 12 months postoperative | 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. |
Countries
Austria
Contacts
CONTACTRobert Breuer, MD
CONTACTValentin Pichler, MD
PRINCIPAL_INVESTIGATORRobert Breuer, MD
Vienna HA
Outcome results
None listed