External venous valves ( at least for the superficial system ) -

" . If reflux is specific to a particular point in gait, for example just prior to the heel touching the ground ,then" external venous valves" might be possible which would prevent reflux being caused by the centrifugal effects generated during gait .

The system would involve bands of electrically responsive material ,which could contract and relax in a rapid fashion , being placed around the leg at appropriate points along its length . The system might be controlled by an accelerometer worn around the ankle and even powered by materials which can produce electrical current by fabric movement . All the bits an pieces for such a system already exist . "

Quote from Podiatry Arena made by me in response to a question .