Here is the design of a clinical trial:

Official Title: Prevention of Thromboembolism and Failed Healing During Lower Limb Immobilization - Multicenter Study With Adjuvant Intermittent Pneumatic Compression Therapy

Included conditions:
- Achilles Tendon Rupture
- Ankle Fractures
- Venous Thromboembolism

Study Armgroups:
- {'label': 'Leg Immobilization', 'type': 'NO_INTERVENTION', 'description': 'Routine care include that the lower limb will be immobilized in an orthosis or a below-knee plaster cast according to local routines.'}
- {'label': 'Adjuvant IPC', 'type': 'EXPERIMENTAL', 'description': 'Leg Immobilization with the addition of IPC. Patients will during lower limb immobilization receive bilateral calf IPC.', 'interventionNames': ['Device: Adjuvant IPC']}

Interventions:
- {'type': 'DEVICE', 'name': 'Adjuvant IPC', 'description': 'This IPC-system delivers sequential circumferential compression. The IPC device is mobile and should therefore not restrict patient mobilization, but can be taken off if the patient wants to mobilize independently.', 'armGroupLabels': ['Adjuvant IPC']}

Primary Outcomes:
- {'measure': 'Venous Thromboembolic Events (VTE)', 'description': 'The primary outcome is VTE defined as symptomatic Deep venous Thrombosis (DVT) or asymptomatic DVTs,or symptomatic pulmonary embolism', 'timeFrame': 'Up til the time of removal of leg immobilization, approx. 6-8 weeks'}

Please estimate the sample size based on the assumption: 
The study uses an alpha of 0.05, a power (1-beta) of 90%, and accounts for a drop-out rate of 5%-10%.
Sample size
          The STOP leg clots is designed on a hypothesis of superiority of adjuvant IPC therapy compared with standard treatment during lower leg immobilisation in prevention of VTE. Based on the existing literature, the expected occurrence of DVT in the control group as detected by screening ultrasound is up to 25% for AF and 50% in ATR.9 10 The estimates are dependent on the case-mix ratio as the incidence of DVT is higher in ATR than in AF. We expect the case-mix to be 30% ATR and 70% AF, resulting in an expected DVT rate of 33%. As extra precautions, we reduced the expected total DVT rate from 33% to 28%. The expected relative risk reduction of DVT is 40% based on earlier studies,32 and we chose to calculate with a lower risk reduction value of 29%. This leads to an absolute risk reduction of DVT of 8%, which is higher than the suggested minimum clinically relevant absolute risk reduction of 4%.9 32 The sample size calculations for the study are based on the following estimates and parameters: alpha=0.05, 1-beta=90%, estimated incidence of DVT=28%, the smallest relative risk reduction to detect=29%. The sample size needed using these study parameters is 597 in each group. Expecting a drop-out rate of 5%â10%âand to compensate for the uncertainty of the final case-mix distribution, we aim to include 1400 patients in our study, around 1000 AF patients and 400 ATR patients.