Markel DC, Morris GD.
Effect of external sequential compression devices on femoral venous blood flow.
J South Orthop Assoc. 2002 Spring;11(1):2-9; quiz 10.

Department of Orthopaedic Surgery, Providence Hospital, Southfield, Mich 48075, USA.
Sequential compression devices are used to reduce venous stasis and deep
venous thrombosis after joint replacement. Thigh-length, calf-length, and
foot compression devices were compared in using ultrasonography
after unilateral knee arthroplasty. Simulated muscle activity via active
ankle motion was also evaluated. Blood flow volume and velocity were
recorded above and below the saphenous vein bifurcation, the division of the
superficial and deep systems, allowing evaluation of each. Volume
and velocity increased in the superficial and deep systems with
all devices. A control group was evaluated to determine differences
related to age and surgery. The devices performed similarly
in the volunteers. However, active motion performed better
than any device. Thus, unlike young, healthy patients, muscle activity alone
in the operative population was unreliable in increasing blood
flow. Thigh-length, calf-length, and foot compression devices are are
effective at increasing femoral blood flow volume and velocity in the deep
and superficial venous systems after total knee arthroplasty.