Here is the design of a clinical trial:

Official Title: Prosthesis Versus Active Exercise Program in Patients With Glenohumeral Osteoarthritis Eligible For Shoulder Arthroplasty: the ProAct Multicenter, Randomized Controlled Trial

Included conditions:
- Glenohumeral Osteoarthritis

Study Armgroups:
- {'label': 'TSA-group', 'type': 'EXPERIMENTAL', 'description': 'Surgery', 'interventionNames': ['Procedure: TSA-group']}
- {'label': 'Exercise-group', 'type': 'EXPERIMENTAL', 'description': 'Exercise', 'interventionNames': ['Other: Exercise-group']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'TSA-group', 'description': 'Anatomical total shoulder arthroplasty followed by standard rehabilitation.', 'armGroupLabels': ['TSA-group']}
- {'type': 'OTHER', 'name': 'Exercise-group', 'description': 'The exercise-group will attend a 12-week exercise program with one weekly physiotherapist-supervised session supplemented with two weekly sessions of home-based exercises. Utilisation of a predefined training protocol describing procedures and content of each session secure uniformity and standardisation of the intervention. The exercise program consists of two warm-up exercises and five exercises that target shoulder range of motion and muscle strength. Furthermore, a link to a video, informing about glenohumeral osteoarthritis, the role of exercise and exercise related pain, will be sent to all patients in the exercise-group. The physiotherapists delivering the exercise intervention are not otherwise related to the trial.', 'armGroupLabels': ['Exercise-group']}

Primary Outcomes:
- {'measure': 'the Western Ontario Osteoarthritis of the Shoulder index (WOOS)', 'description': 'WOOS consist of 19 items to be answered using a visual analog scale (VAS). Each item has a possible score ranging from 0 to 100, leading to a total WOOS score ranging from 0 to 1900, with 0 being the best. For simplicity reasons, raw scores can be converted to a percentage of the maximum score (0-100, 100 best).', 'timeFrame': 'Measured at 12-month follow-up'}

Please estimate the sample size based on the assumption: 
The significance level is set at 5%, the power is 80%, and the dropout rate is assumed to be 30%.
Sample size
        The sample size calculation is based on WOOS data from the Danish Shoulder Arthroplasty Register and on end scores obtained from the feasibility study. The median WOOS score 1 year after surgery for patients with glenohumeral OA treated with TSA is 85 points (Danish Shoulder Arthroplasty Registry [DSR] 2020). The assumed SD was 27, calculated from the interquartile range (IQR). After completing the exercise intervention in the feasibility study, the WOOS score was a mean 67 (SD 22). With a 5% level of significance and a sample size of 78 patients, the study will have 80% power to detect an 18-point difference in the end scores between the surgical and exercise group. Assuming a 30% dropout rate, the total number of patients needed is 102.