Previous cancer history increases chances of VTE after knee arthroscopy

A history of cancer is a significant risk factor for developing venous thromboembolism after knee arthroscopy, according to researchers from the Mayo Clinic.

The findings were presented at the 2011 Annual Meeting of the American Orthopaedic Society for Sports Medicine in San Diego.

“Knee arthroscopy is the most commonly performed operation in the United States, however, data on the risk of sympomatic venous thromboembolitic (VTE) events are limited and most published studies include relatively small numbers,” study author Diane L. Dahm, MD, said in her presentation. “The purpose of our study was to determine the incidence of clinically relevant VTE following knee arthroscopy, and to evaluate the potential risk factors associated with VTE.”

Study methods and parameters

Dahm and her team reviewed the records of arthroscopy patients from a single institution who underwent their procedure between 1985 and 2005. Any VTE events that occurred within 4 weeks of the arthroscopic procedure were recorded. The team also put together a 2:1 matched control group consisting of patients who had undergone knee arthroscopy with the same surgeon either on the same day or immediately prior to those cases which ultimately resulted in VTE.

Demographic, previous medical history, surgical and anesthesia data were all collected preoperatively and perioperatively, and the authors noted chemoprophylaxis was not routinely used.

Risk factors

Overall, Dahm reported, 12,595 patients underwent knee arthroscopy during the study period with 43 identified cases of VTE — including 35 cases of deep vein thrombosis (DVT), 5 pulmonary embolisms and 3 DVTs that eventually progressed to pulmonary embolism — for an incidence rate of 0.30% for DVT and 0.06% for PE.

The findings showed that a history of malignancy and a history of prior VTE were associated with a higher risk of postoperative VTE. The presence of two or more classic VTE risk factors also pointed toward an increased risk of VTE after knee arthroscopy.

“We therefore recommend consideration of chemoprophylaxis to prevent VTE in high-risk patients following knee arthroscopy,” Dahm said.

Reference:

Morgan JA, Krych AJ, May JH, et al. Incidence of symptomatic venous thromboembolism after knee arthroscopy. Paper #08-10022. Presented at the 2011 Annual Meeting of the American Orthopaedic Society for Sports Medicine. July 7-10. San Diego.

Disclosure: The authors have no relevant financial disclosures.

The article on the incidence of discovered VTE by Dr. Dahm et al. from the Mayo Clinic is an interesting perspective on a potentially devastating complication from a routine surgery. In this well-done review study of well over 12,000 cases, they found 43 cases of symptomatic VTE with at least 5 pulmonary embolism, as well as an additional 3 DVT cases that progressed to PE. Associated with an increased incidence of VTE were a past medical history of previous VTE or cancer.

The study highlights those patients at higher risk of developing symptomatic VTE, allowing the treating physician to take prophylactic steps in these higher risk patients. It should be recognized that the study only evaluated symptomatic patients, not those who may have had an asymptomatic thrombosis. The take-home message for us: patients with a prior history of VTE events or those with a past history of cancer require close observation for thromboembolic events.

— Felix H. Savoie, III, MD
Department of Orthopaedic Surgery Tulane
University School of Medicine

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