Comparison of Stemless and Stemmed Shoulder Arthroplasty for Osteoarthritis

Study Overview
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Brief Summary
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This is a randomized controlled trial comparing the Comprehensive Nano stemless total shoulder arthroplasty (intervention group) with the Comprehensive un-cemented stemmed total shoulder arthroplasty (control group). All Danish citizens with glenohumeral osteoarthritis indicating a total shoulder arthroplasty referred to the orthopedic department at Copenhagen University Hospital in Gentofte will be offered participation in the trial. The following exclude from participation in the study: below 18 years of age; cognitive or linguistic impairment; insufficient function of the rotator cuff; poor bone quality and ASA group 4-5. A total of 122 patients will be included of which 56 will be part of radiostereometric analysis (RSA) study of humeral component migration. This will allow a maximum of 20% drop out. The primary outcome is magnitude and pattern of migration of the humeral component assessed by RSA. The secondary outcomes are patient-reported outcomes, functional outcome, readmission, complications, revisions, changes in bone mineral density (BMD) of the proximal humerus assessed by duel energy x-ray absorptiometry (DXA) and economy (cost utility analysis). To avoid bias in some of these outcomes, the patient will not know what type of humeral component was used. The patients are examined before the operation and 3, 6, 12 and 24 months after the operation.

Detailed Description
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Background Osteoarthritis (wear and tear) of the shoulder can, in the most severe cases, require insertion of shoulder prosthesis (an artificial shoulder joint, a total shoulder arthroplasty). This is an effective treatment with pain-relief and significant improvement in shoulder function. A design with a metal stem in the humeral bone canal is currently regarded as the best treatment option, but complications related to the stem including humeral fractures can have devastating consequences. By using a stemless humeral component stem-related complications can be reduced. Furthermore, the canal preserving design may also facilitate further surgery should the need of a revision prosthesis arise. Currently, little is known about the results of the stemless design. The initial results have been promising, but as with the stemmed design migration and eventually loosening of the prosthesis can lead to poor results and, in some cases, revision. Using radiostereometric analysis (RSA) a special x-ray examination technique based upon insertion of small metal beads into the bone surrounding an implant and attachment of beads to the prosthesis (or using 3-dimensional models of the implant (CAD models) = model-based RSA (MB-RSA)), implant migration can be measured extremely accurate. The RSA technique has previously been used to study migration and loosening of hip and knee prostheses. It has been suggested that RSA should be used to monitor small series of new prostheses the first two years after surgery as a part of a safe phased introduction. RSA has never been used to access migration of a stemmed or a stemless humeral component nor has the stemmed and the stemless humeral component been compared with regard to pain relief and shoulder function. Purpose The purpose is to compare the Comprehensive Nano stemless total shoulder prosthesis (intervention group) with the Comprehensive stemmed total shoulder prosthesis (control group). Method All Danish citizens with shoulder osteoarthritis indicating a total shoulder arthroplasty referred to the orthopedic department at Copenhagen University Hospital in Gentofte will be offered participation in the trial. The following exclude from participation in the study: below 18 years of age, cognitive or linguistic impairment, insufficient function of the rotator cuff (muscles which stabilize the shoulder joint) and severe co-morbidity (ASA-score 4-5). A total of 122 patients will be included of which 56 will be part of the RSA analysis. This will allow a maximum of 20% drop out. The study will be conducted as a randomized clinical trial (RCT) where each participant by lot will be allocated to one of the two designs. Patients will subsequently be carefully monitored to determine whether there is a difference. The primary outcome is magnitude and pattern of migration of the humeral component assessed by MB-RSA. The secondary outcomes are pain relief, questionnaires (patient-reported outcome), range of movement and strength (functional outcome), readmission, complications, revisions, changes in bone density round the shoulder assessed by duel energy x-ray absorptiometry (DXA) and economy (cost utility analysis). To avoid bias in some of these outcomes, the patient will not know what type of prosthesis was used. The patients are examined before the operation and 3, 6, 12 and 24 months after the operation. The investigators expect short-term publications of early results at about 2 years after inclusion of the last patient. Ethical considerations Apart from the differences in design, the two groups are treated alike. Today, the two designs are considered equal in the treatment of osteoarthritis. With this study, all patients are at risk of being treated with a prosthesis that subsequent analyses will deem inferior. This is implicit in the study design and there is nothing a priori to suggest which prosthesis is the better. The standard treatment at the orthopedic department at Copenhagen University Hospital in Gentofte includes preoperative planning with plain radiographs, CT and MRI scans of the glenohumeral joint and follow-up examinations with plain radiographs postoperatively and at 3 months. In addition to this standard treatment the participating patients will have additional radiographic examinations including: RSA examination at 1 week, 3 months, 6 months, and at 1 and 2 years: 0.04 mSv Plain radiographs at 1 and 2 years: 0.02 mSv DXA scans preoperatively, at 1 week, 3 months, 6 months, and at 1 and 2 years: 0.04 mSv The background radiation in Denmark is 3 mSv each year. The extra radiation dosage of 0.10 mSv from this study corresponds to the background radiation during approximately 12 days. The standard treatment at the orthopedic department at Copenhagen University Hospital in Gentofte includes a follow-up examination at 3 months. The participating patients will have additional follow-up examinations at 1 week, 6 months, and at 1 and 2 years. Besides being time consuming this may maintain the patients in a role of being ill. However, the patients will also have the advantage of feeling secure and any uncertainty or problems can be addressed more easily. The results of the study should be of benefit to future patients with osteoarthritis of the shoulder and thereby also for the use of resources in healthcare. Neither the coordinating investigator nor participating investigators or surgeons have personal economic interests in the study results.

Official Title
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Early Migration of Stemless and Stemmed Humeral Components After Total Shoulder Arthroplasty for Osteoarthritis - A Randomized Controlled Trial

Conditions
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Glenohumeral Osteoarthritis

Intervention / Treatment
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* Procedure: Shoulder arthroplasty


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All Danish citizens with glenohumeral osteoarthritis indicating a total shoulder arthroplasty referred to the orthopedic department at Copenhagen University Hospital in Gentofte Exclusion Criteria: below 18 years of age cognitive or linguistic impairment insufficient function of the rotator cuff poor bone quality ASA group 4-5

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Based on the sample calculation the investigators intend to include a total number of 122 patients of which the first 56 patients will be studied using MB-RSA and DXA. The patients are allocated into two groups of equal of size: The un-cemented Comprehensive Nano stemless shoulder arthroplasty (intervention group) The un-cemented Comprehensive stemmed total shoulder arthroplasty (control group) The randomization is done in the operating theater just after the perioperative evaluation of the bone-stock and the rotator cuff. The randomization sequence will be computer generated. The patients will be randomized using stratified, block randomization.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Un-cemented Comprehensive Nano stemless shoulder arthroplasty<br>By using a stemless humeral component stem-related complications can be reduced. Furthermore, the canal preserving design may also facilitate further surgery should the need of a revision prosthesis arise. Currently, little is known about the results of the stemless design. The initial results have been promising, but as with the stemmed design migration and eventually loosening of the prosthesis can lead to poor results and, in some cases, revision | Procedure: Shoulder arthroplasty<br>* Patients suffering from severe glenohumeral osteoarthritis are treated surgically by a total shoulder arthroplasty<br>|
| Active Comparator: Un-cemented Comprehensive stemmed total shoulder arthroplasty<br>A design with a metal stem in the humeral bone canal is currently regarded as the best treatment option, but complications related to the stem including humeral fractures can have devastating consequences. | Procedure: Shoulder arthroplasty<br>* Patients suffering from severe glenohumeral osteoarthritis are treated surgically by a total shoulder arthroplasty<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Radiostereometric analysis (RSA) | A special x-ray examination technique based upon insertion of small metal beads into the bone surrounding an implant and attachment of beads to the prosthesis (or using 3-dimensional models of the implant (CAD models) = model-based RSA (MB-RSA)). In this way, implant migration can be measured extremely accurate. | Change from 1 week postoperatively to 3 months, 6 months, and at 1 and 2 years postoperatively | 
| Western Ontario Osteoarthritis of the Shoulder index (WOOS) | The WOOS is a disease-specific patient-reported outcome (Lo IK et al 2001). There are 19 questions divided into four domains: Physical symptoms, sports and work, lifestyle and emotions. Each question is answered on a visual analogue scale ranging from 0 to 100. The overall score ranges from 0 to 1900, with 1900 being the worst. For ease of interpretation, the scores are converted to a percentage of the maximum score. We use a Danish version of WOOS (Rasmussen JV et al 2013) which was translated according to the guidelines of Guillemin, Bombardier and Beaton (Guillemin F et al 1993). It was validated with classical test theory in a cohort of patients treated with shoulder arthroplasty for osteoarthritis. | Change in WOOS score from preoperatively to 3 months, 6 months, and at 1 and 2 years postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duel energy x-ray absorptiometry (DXA) | Changes in bone mineral density (BMD) in close relation to an orthopedic implant can be measured by duel x-ray absorptiometry (DXA) | Preoperatively and at 1 week, 3 months, 6 months, and at 1 and 2 years postoperatively | 
| Plain radiographs | We use an anterior-posterior and a lateral view. The radiographs are used to evaluate the position of the component and to evaluate loosening as the cause of failure. | Preoperatively and at 1 week, 3 months and at 1 and 2 years postoperatively | 
| Oxford Shoulder Score (OSS) | Oxford Shoulder Score (OSS): The OSS was conceived as a measurement tool for the assessment of pain and function after elective shoulder surgery (Dawson J et al 1996). There are 12 questions with each item scored from 1-5. The overall score ranges from 12 to 60, with 60 being the worst. For ease of interpretation, the scores are converted to a percentage of the maximum score. We use a Danish version of OSS which was translated and validated with classical test theory (Frich LH et al 2011). | Preoperatively and 3 months, 6 months, and at 1 and 2 years postoperatively | 
| Constant-Murley score | The Constant-Murley Score includes an assessment of: pain; activities of daily living (ADL); range of motion; and strength. There are a possible 35 points given for the subjective assessment of pain and the ability to perform ADL. There are a possible 65 points given for an objective assessment, of which 40 points are allocated to range of motion and 25 points are allocated to strength. The maximum of 100 point indicates a shoulder with no disability. We use a Danish version (Ban I et al 2013) of the modified score described by Con¬stant and colleagues in 2008 (Constant CR et al 2008). | Preoperatively and 3 months, 6 months, and at 1 and 2 years postoperatively | 
| Pain and patient-satisfaction: visual analogue scale (VAS) | Pain is answered on a visual analogue scale (VAS) ranging from 0 to 10, with 10 being the worst. Patients are asked to categorize the result as excellent, very good, good, fair and poor. | 3 months, 6 months, and at 1 and 2 years postoperatively | 
| Side effects and complications | We will record any case of medical complications (embolism, cardiovascular event, pneumonia) and complications related to the surgical procedure (fractures, nerve injuries, deep and superficial infections, malpositioning of the components, instability, and dislocation) and revisions defined by removal or exchange of any component. | 2 years postoperatively | 
| Cost-utility analysis | In modern health economics, thresholds have been estimated for acceptable cost-utility ratios - the threshold for how much health care providers will pay for an extra quality- adjusted life year (QALY). In England and in Europe, the threshold for an extra QALY is set at 20,000-30,000 pounds and 30,000 Euros respectively. The cost utility of the Comprehensive Nano stemless shoulder arthroplasty will be compared with these thresholds and with the cost utility of the uncemented Comprehensive stemmed total shoulder arthroplasty. The EQ-5D will be used to estimate QALY for individual patients. | 2 years postoperatively | 
| Length of hospital stay | How long time the patients are hospitalized postoperatively. The data will be extracted from the medical records. | 3 months postoperatively | 
| Discharge destination | Whether the patients are discharged to home, rehabilitation or nursing home. The data will be extracted from the medical records. | 3 months postoperatively | 
| Pain medication usage | Which kind and how much pain medication each patients have used. The data will be extracted from the medical records. | 2 years postoperatively |