He adds, "I would feel very uncomfortable using the rates from this study in counseling a patient, because I think they (the authors) underestimate the true risk."
Heit says that the other problem with the analysis these researchers produced was that most of the data came from randomized controlled trials, which are structured to exclude patients who are older, and sicker and have multiple co-morbidities, the very patients who might be more likely to have higher rates of VTE.
Additionally, the researchers' report assumed patients remained in the hospital for up to 14 weeks, when today, most patients with hip or knee replacement surgery are discharged after the third or fourth postoperative day, Heit says.
The issue is further confused by statements from the American Academy of Orthopaedic Surgeons, which says that for patients with total hip replacement, 7% develop deep vein thrombosis and .3% develop a pulmonary embolism within 90 days of surgery. For total knee replacement patients, .9% develop deep vein thrombosis and .3% develop a pulmonary embolism within 90 days of surgery.
Heit says that the issue remains extremely controversial "because there's such a lack of good data on what is most effective, and what's most safe."