April 2011

Deconstructing DVT

In the moment: Rehabilitation

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Seeking strategies for foot and ankle

By Jordana Bieze Foster

As followers of sports and pop culture were absorbing the news of tennis star Serena Williams’ pulmonary embolism, researchers and clinicians at the annual meeting of the American College of Foot & Ankle Surgeons were discussing strategies for minimizing the risk of such vascular events after surgery.

Williams, 29, cut a tendon in her foot when she stepped on broken glass shortly after winning the Wimbledon singles championship last July. She had the tendon repaired surgically, but re-tore it while preparing to return to competition and required another surgery in mid-October.  According to news reports, the foot was immobilized (first in a cast, then a walking boot) until February; shortly after the boot was removed, she developed a pulmonary embolism that required her to be hospitalized in mid-February, although it was almost two weeks before that news became public.

Presenters at the ACFAS meeting in early March did not specifically address the tennis star’s case. But the current lack of data on risk of vascular complications after foot and ankle surgery and the lack of guidelines for use of prophylactic antithrombotic medications were topics that came up repeatedly throughout the meeting.

“There’s very little data in the literature relative to foot and ankle surgery and risk of deep venous thrombosis or pulmonary embolism,” said Peter Blume, DPM, who practices with Affiliated Foot Surgeons in New Haven, CT, and is a clinical instructor in orthopaedics and rehabilitation at the Yale University School of Medicine.

As a result, foot and ankle surgeons have had to extrapolate from published studies on vascular complications following hip or knee surgery, primarily total joint arthroplasty. Guidelines on DVT prophylaxis issued by the American College of Chest Physicians and the American Academy of Orthopaedic Surgeons address TKA and THA but not foot and ankle procedures.

So it may not be surprising that a 2004 survey of orthopedic surgeons published in Orthopedics found that only 44% used thromboembolic prophylaxis when treating foot and ankle trauma. Risk of bleeding associated with antithrombotic drugs is a particular concern in lower extremity surgery; Williams, in fact, ended up in the hospital with a hematoma on Feb. 28 following a self-administered antithrombotic injection gone awry.

“There’s a lot of grey area as to who we prophylax and who we do not,” Blume said.

In a systematic review presented at the ACFAS meeting, researchers from Madigan Army Medical Center in Tacoma, WA, singled out only eight prospective studies that addressed pharmacological antithrombotic prophylaxis for patients with foot and ankle pathology, and only one of those was a level one study. In the five studies on postoperative patients, pharmacological prophylaxis was implemented in 78.9% of cases; incidence of DVT was 3.3% and incidence of PE was 0.12%. In the three studies on conservatively treated patients, prophylaxis was used in 58.2% of cases; incidence of DVT was 5.9% and incidence of PE was .03%. However, six of the eight studies excluded patients with known risk factors for DVT (which include immobilization, age over 40, obesity, rearfoot surgery, and injury severity).

In another study presented at the ACFAS meeting, researchers from Marin Foot & Ankle Center and Palmetto General Hospital in south Florida reported a 1.8% incidence of venous thromboembolism in 342 foot and ankle surgery patients who received no prophylaxis; all occurred in rearfoot cases, where the incidence increased to 3.6%. A protocol was then implemented requiring mechanical and pharmacological prophylaxis in any patient with three or more risk factors for DVT; of the next 963 patients, only one (a bunionectomy case) experienced a VTE, for an incidence of 0.1%. No complications were reported.

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