Here is the design of a clinical trial:

Official Title: A Prospective Randomised Control Trial Comparing Mako Robotic-arm Assisted Functionally Aligned Total Knee Arthroplasty Versus Mako Robotic-arm Assisted Mechanically Aligned Total Knee Arthroplasty

Included conditions:
- Osteo Arthritis Knee
- Osteoarthritis
- Surgery

Study Armgroups:
- {'label': 'Mechanically aligned', 'type': 'ACTIVE_COMPARATOR', 'description': "Neutral limb alignment irrespective of the patient's native knee anatomy and joint mechanics", 'interventionNames': ['Device: Total knee arthroplasy']}
- {'label': 'Functionally aligned', 'type': 'EXPERIMENTAL', 'description': "Restore the patient's own pre-arthritic knee anatomy", 'interventionNames': ['Device: Total knee arthroplasy']}

Interventions:
- {'type': 'DEVICE', 'name': 'Total knee arthroplasy', 'description': 'Surgical implantation of prosthetic knee using robotic-arm assist', 'armGroupLabels': ['Functionally aligned', 'Mechanically aligned']}

Primary Outcomes:
- {'measure': 'Western Ontario and Mcmaster Universities Arthritis Index (WOMAC)', 'description': 'Patient recorded outcome questionnaire evaluating pain, stiffness and disability in affected joint', 'timeFrame': '2 years post-intervention'}

Please estimate the sample size based on the assumption: 
A two-tailed, two-sample t test with a power of 90%, a significance level of 5%, and an expected drop-out rate of 10% during the 2-year follow-up period.
Sample size
        Using data from a previous study recording functional outcomes, the mean WOMAC score at 2âyears using MA TKA was 26 (standard deviation 22.6) and using TKA with kinematic alignment was 15 (standard deviation 20.3) [14]. Using a two-tailed, two-sample t test with an effect size of 0.35, power of 90% with significance level of 5%, and accounting for an expected drop-out rate of 10% during the 2-year follow-up period, the study requires 100 patients to detect a minimal clinically important difference of 11 points in the total WOMAC score between the two treatment groups [13].