Inferior vena cava filter placement in orthopedic surgery.

Inferior vena cava (IVC) filters were developed for the treatment of venous thromboembolism but in high-risk patients are often used for prophylaxis instead. In the study reported here, we reviewed all the orthopedic surgery cases in which IVC filters were used at our institution in 2005. Charts were analyzed and patients contacted by telephone for long-term follow-up. IVC filters were used in 90 (0.96%) of the 9,348 inpatient orthopedic surgeries. Sixty-one percent of filters were placed for prophylaxis, though only 42% of patients with prophylactic filters had a contraindication to anticoagulation. Eighty-one percent of patients with prophylactic filters who received anticoagulation received warfarin. Ratios of prophylactic-to-treatment filters were 3.25 for fracture surgeries, 2.1 for arthroplasties, and 0.89 for spine surgeries. Five percent of patients with prophylactic filters developed deep vein thrombosis. Fifty-two percent of filters were retrievable, but only 40% of those were removed a mean of 5.1 months (SD, 3.9 months) after placement. Filter removal was associated with complications in 11% of patients, and in another 10% the filter could not be removed. Forty-one patients were contacted a mean of 21 months (SD, 3 months) after filter placement. Only 32% of those who still had filters were on anticoagulation at follow-up.