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

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.

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.

Research subjects receive lower limb immobilisation with cast and with orthosis alternatively, randomised so as subsequent persons begin with different modality.

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