Comparison of the Effects of Lower Limb Immobilisation With Cast and Orthosis

Study Overview
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Brief Summary
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In this study we are going to measure the blood flow in the lower limbs under cast immobilisation and also under mobilisation with an orthosis. The aim is to evaluate how the aforementioned modalities affect the blood flow and also to compare between the two.

Detailed Description
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Background: Lower limb immobilisation, for example after an Achilles tendon rupture, is known to be a cause for DVT, partly due to blood stasis. VACOped is a weight-bearing orthosis with adjustable range of motion of the ankle which is used in our department in patients operated for Achilles tendon rupture. Aim: To assess the effects of a) lower leg casting in equinus without loading and b) application of the aforementioned orthosis with full weight baring in blood flow and microcirculation in the lower limbs. Study Plan: Ten healthy individuals are planned to be recruited for this study. Blood flow in the Right popliteal will be measured with vein before, 30 and 60 min after the application of the cast or orthosis (alternate order between consequent individuals) with Duplex Ultrasound. The orthosis will be set to allow for ankle plantarflexion restricted between 15 and 30 degrees. Tissue oxygen saturation in the lower limbs will also be measured using a somatic regional oxymetry modality, INVOS, with adhesive sensors applied on each leg above the soleus.

Official Title
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The Effects of Different Types of Ankle Immobilisation in the Micro- and Macrocirculation

Conditions
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Venous Stasis, Deep Venous Thrombosis

Intervention / Treatment
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* Device: Orthosis VACOped
* Device: Below knee cast


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy individuals Exclusion Criteria: Severe cardiovascular or renal disease causing pitting oedema Previous operation in the lower limbs affecting the vascular or lymphatic system Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Research subjects receive lower limb immobilisation with cast and with orthosis alternatively, randomised so as subsequent persons begin with different modality.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Cast immobilisation<br>A below knee cast is applied in order to achieve ankle immobilisation for one hour | Device: Below knee cast<br>* Below knee cast for lower limb immobilisation<br>* Other names: Plastrer cast of Paris;|
| Experimental: Orthosis (VACOped) immobilisation<br>A below knee orthosis which allows for ankle movement is applied for one hour. | Device: Orthosis VACOped<br>* Orthosis for lower limb immobilisation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The difference of the effect on the lower limb circulation between cast and VACOped immobilisation | Duplex ultrasound (blood flow) and INVOS (regional tissue mixed saturation) | 2.5 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lower limb macrocirculation under cast immobilisation | Duplex ultrasound (blood flow) | 1 hour | 
| Lower limb microcirculation under cast immobilisation | INVOS (regional tissue mixed saturation) | 1 hour | 
| Lower limb macrocirculation under orthosis mobilisation | Duplex ultrasound (blood flow) | 1 hour | 
| Lower limb microcirculation under orthosis mobilisation | INVOS (regional tissue mixed saturation) | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cast, orthosis, immobilisation, venous stasis, circulation