Here is the design of a clinical trial:

Official Title: Elbow Hemiarthroplasty Versus Open Reduction and Internal Fixation for AO/OTA Type C2 and C3 Fractures of Distal Humerus in Patients Aged 50 Years or Above; a Randomized Controlled Trial

Included conditions:
- Distal Humerus Fracture
- Comminuted Fracture
- Intra-Articular Fractures

Study Armgroups:
- {'label': 'Elbow hemiarthroplasty', 'type': 'ACTIVE_COMPARATOR', 'description': 'The Latitude anatomical hemiarthroplasty (WRIGHT -Memphis, Tennessee) for distal humeral fractures.', 'interventionNames': ['Procedure: Surgical treatment of distal humeral fracture with elbow hemiarthroplasty']}
- {'label': 'Open reduction and internal fixation', 'type': 'ACTIVE_COMPARATOR', 'description': 'Double plating (Synthes - Switzerland and West Chester, Pennsylvania, United States) for distal humeral fractures.', 'interventionNames': ['Procedure: Surgical treatment of distal humeral fracture with double plating.']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Surgical treatment of distal humeral fracture with elbow hemiarthroplasty', 'description': 'Latitude anatomical elbow hemiarthroplasty (WRIGHT -Memphis, Tennessee)', 'armGroupLabels': ['Elbow hemiarthroplasty']}
- {'type': 'PROCEDURE', 'name': 'Surgical treatment of distal humeral fracture with double plating.', 'description': 'Double plating (Synthes - Switzerland and West Chester, Pennsylvania, United States)', 'armGroupLabels': ['Open reduction and internal fixation']}

Primary Outcomes:
- {'measure': 'Oxford Elbow Score (OES)', 'description': 'The OES is a 12-item patient-administrated questionnaire that measures the quality of life in patients with elbow disorder. There are three unidimensional domains: Elbow function, pain, and social-psychological status. Each question is answered on a 5-point scale with each question contributing equally to the total score.Thus, the total score ranges from 12-60, with 60 being the worst. For ease of presentation the score is converted to a scale from 0-48 with 48 being the best. The outcome can be interpreted based on a 48-point scale: 0 - 19 - poor; 20-29 - fair; 30-39 - good; and 40-48 - excellent. The Danish version which will be used in this study, has been translated and cultural adapted according to the guidelines by Guillemin, Bombardier and Beaton.', 'timeFrame': '2 years after surgery.'}

Please estimate the sample size based on the assumption: 
Standard deviation (SD) of 16, significance level at 0.005, power of 0.80, and an 18% dropout rate
Sample size calculation OES
          Oxford elbow score (OES) will be used to measure the primary outcome.
          Sample size calculation was performed with a standard deviation (SD) of 16, a MCID of 15, a significance level at 0.005, and power of 0.80, resulting in 18 participants in each group (44 participants in all with allowance for 18% drop-out).
          The estimation of SDâ=â16 is extrapolated from a study on 24 patients with distal humeral fractures treated with EHA [1]. There is no MCID defined for the total score of OES, but Dawson et al. have reported the MCID for each of the three domainsâpain, function, and social-psychologicalâfor a group of patients with different pathologies including TEA for osteoarthritis and rheumatoid arthritis. MCID for the three domains is 19, 9, and 18, respectively [5]. Accordingly, we chose the MCID to be 15.