Here is the design of a clinical trial:

Official Title: A Pragmatic Multi-centre Blinded Randomised Placebo-controlled Trial Comparing Platelet Rich Plasma Injection (PRP) to Placebo (Imitation) Injection in Adults With Achilles Tendon Rupture

Included conditions:
- Achilles Tendon Rupture

Study Armgroups:
- {'label': 'PRP Injection', 'type': 'ACTIVE_COMPARATOR', 'description': "Intervention - PRP Injection: The injection is the intervention. A blood sample is withdrawn from patient. Away from patient part of sample is spun down in centrifuge to produce 'Platelet Rich Plasma' (PRP). Patient returns to treatment area and their own PRP is then injected into tendon rupture gap. This is carried out by a surgeon or extended scope physiotherapist, generally in the outpatient clinic, after a local anaesthetic has been applied. Patient is lying face down during procedure, unaware of treatment given to tendon at back of leg. Remaining blood sample sent for analysis.", 'interventionNames': ['Procedure: PRP Injection into Achilles tendon rupture gap']}
- {'label': 'Imitation Injection', 'type': 'SHAM_COMPARATOR', 'description': 'Sham - Imitation Injection: The injection is the intervention. A blood sample is withdrawn from patient. Treatment is prepared. Patient returns to treatment area and a needle (no syringe) is inserted and held into tendon rupture gap to mimic injection (after local anaesthetic has been applied). No active ingredient given. Carried out by surgeon or extended scope physiotherapist, generally in the outpatient clinic. Patient is lying face down during procedure, unaware of treatment given to tendon at back of leg. Blood sample sent for analysis.', 'interventionNames': ['Procedure: Imitation Injection into Achilles tendon rupture gap']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'PRP Injection into Achilles tendon rupture gap', 'description': "PRP injection delivered into the tendon rupture gap Intervention - PRP Injection: The injection is the intervention. A blood sample is withdrawn from patient. Away from patient part of sample is spun down in centrifuge to produce 'Platelet Rich Plasma' (PRP). Patient returns to treatment area and their own PRP is then injected into tendon rupture gap. This is carried out by a surgeon or extended scope physiotherapist, generally in the outpatient clinic, after a local anaesthetic has been applied. Patient is lying face down during procedure, unaware of treatment given to tendon at back of leg. Remaining blood sample sent for analysis.", 'armGroupLabels': ['PRP Injection']}
- {'type': 'PROCEDURE', 'name': 'Imitation Injection into Achilles tendon rupture gap', 'description': 'Imitation injection delivered into the tendon rupture gap Sham - Imitation Injection: The injection is the intervention. A blood sample is withdrawn from patient. Treatment is prepared. Patient returns to treatment area and a needle (no syringe) is inserted and held into tendon rupture gap to mimic injection (after local anaesthetic has been applied). No active ingredient given. Carried out by surgeon or extended scope physiotherapist, generally in the outpatient clinic. Patient is lying face down during procedure, unaware of treatment given to tendon at back of leg. Blood sample sent for analysis.', 'armGroupLabels': ['Imitation Injection']}

Primary Outcomes:
- {'measure': 'Heel-Rise Endurance Test (HRET)', 'description': 'Muscle-tendon function, measured objectively with the limb symmetry index (LSI) in maximal work during the heel-rise endurance test (HRET) \\[ Time Frame: 24 weeks following study treatment \\] The HRET is a validated objective performant test of calf-muscle Achilles tendon capacity to work, which is measured in the unit joules (J). The HRET involves the participant standing on one leg and raising and lowering the heel repeatedly until fatigued. The work during the HRET for each lower limb is measured. The performance of each limb is then converted into a limb symmetry index, which is the primary outcome metric from the HRET.', 'timeFrame': '24 weeks following study treatment'}

Please estimate the sample size based on the assumption: 
90% power, 5% (two-sided) significance level, and 20% loss to follow-up. Later adjusted to a minimum of 80% power with the same significance level and loss to follow-up.
Sample size
        A total number of 214 patients (107 per arm) will provide 90% power to detect a standardised difference of 0.5 in the LSI measured at 24Â weeks post treatment, with 5% (two-sided) significance and allowing 20% losses to follow-up. This is based on data from the non-surgical arm of a previous study [4], where a clinically important difference of 10% with a standard deviation (SD) of 20 was observed. This sample size will also provide 90% power and 5% (two-sided) significance to detect a standardised effect size of 0.5 in the Achilles Tendon Rupture Score (ATRS; patient reported outcome) between the two intervention groups, based on a difference of 11 and an SD of 21.4.
        However, this sample calculation was inflated as a result of a pre-specified blinded check of the assumptions for the primary outcome variability, which took place approximately halfway through recruitment using the overall population data (total sample, rather than intervention groups separately), as recommended by the Data and Safety Monitoring Committee (DSMC). As of June 2017, approximately half of the patients had reached their primary end-point and recruitment was still ongoing. Using cleaned and validated data from 75 patients, the observed SD was 24. Based on this observed SD of 24 (being aware that this could go up or down with the addition of further patient data), the sample size was recalculated.
        Therefore, based on a minimum of 80% power, and allowing for 20% loss to follow-up, a sample size of 226 patients would be required to identify a clinically important difference of 10% with an SD of 24. The DSMC advised us during this process, and it was decided that the recruitment should overshoot to a minimum of 230 patients (to account for further minimal fluctuations on sample size assumptions) as a feasible target in the remaining timelines of the trial. This approach was supported by the Trial Steering Committee (TSC).