Bone vacuum cuts clot risk after hip replacement

[Guest guest]

Bone vacuum cuts clot risk after hip replacement

NEW YORK, Feb 07 (Reuters Health) - Using a bone vacuum during hip

replacement surgery reduces the chance that a patient will develop

life-threatening blood clots after the operation, researchers report.

Patients who have hip or knee replacement surgery are at risk of

developing blood clots known as deep-vein thrombosis (DVT) within their

leg veins. These clots can dislodge and travel to the lungs, resulting

in a potentially fatal condition known as pulmonary embolism.

Hip replacement requires that part of the artificial joint be anchored

in the marrow of the thighbone, or femur. The increased pressure within

the bone during the insertion can make particles of fat, bone marrow and

cement more likely to travel into the bloodstream, where they can lead

to blood clots, Dr. Rocco Paolo Pitto from the University of Auckland in

New Zealand and colleagues theorized.

To investigate whether preventing fat and bone marrow particles from

entering the bloodstream during surgery could prevent DVT and pulmonary

embolism, Pitto's team selected 130 patients undergoing hip replacement

to have the component inserted either with or without the use of a bone

vacuum technique.

The technique involves using a vacuum to suction out particles from

within the insertion site before cementing the prosthesis in place. The

vacuuming also helps prevent a rise in pressure within the bone during

insertion.

Imaging tests performed while the components were being inserted showed

that a cascade of small particles were released into the bloodstream in

59 of the 65 patients treated without the vacuum, or 91%. The particle

cascade was seen in only 10 patients treated with the vacuum, or 15%. In

addition, the intensity and duration of these events was significantly

reduced in vacuum-treated patients.

Ultrasound tests 4 days after the operation showed that 12 of the

patients treated without the vacuum (18%) had DVT, while only 2 of the

patients (3%) treated with the vacuum did. The results are published in

the January issue of The Journal of Bone and Joint Surgery.

" To our knowledge, the present study is the first randomized clinical

trial designed to investigate the relationship between intraoperative

fat and bone-marrow embolism and thrombosis of the deep venous system, "

Pitto and colleagues write. The current findings seem to confirm the

hypothesis that a reduction in embolic, or blood vessel-obstructing,

events during surgery lowers the risk of DVT after the operation.

There is controversy regarding the best way to prevent DVT in patients

who have total hip replacements, the authors point out. Regardless of

what doctors do after surgery, the investigators recommend that surgeons

use some type of clot-preventing strategy during the operation, such as

the bone vacuum technique.

SOURCE: The Journal of Bone and Joint Surgery 2002;84-A:39-47.