What is the risk of deep vein thrombosis after knee arthroscopy?

In patients undergoing knee arthroscopy, approximately 6% will develop a deep vein thrombosis (DVT) or symptomatic pulmonary embolism (PE). If these data are translatable to other settings, thromboprophylaxis would appear to be unnecessary. (LOE = 1b-)

Hoppener MR, Ettema HB, Henny CP, Verheyen CC, Buller HR. Low incidence of deep vein thrombosis after knee arthroscopy without thromboprophylaxis: a prospective cohort study of 335 patients. Acta Orthopaedica 2006;77:767-771.  [PMID:17068708]

Cohort (prospective)

Industry

Outpatient (specialty)

These authors followed 355 consecutive patients undergoing outpatient knee arthroscopy. The patients didn't receive DVT prophylaxis. In addition to asking patients about symptoms suggesting DVT or PE, the researchers had patients undergo noninvasive testing for DVT 14 days after surgery. The authors don't report whether either of these were assessed in a blinded fashion. At the end of the 8-week follow-up period, the authors had data on 335 (94%) of the patients. They found 19 (5.7%; 95% CI, 3.5%-8.7%) DVTs on ultrasound, 2 of which appeared to be symptomatic. One patient, who did not have a DVT by ultrasound, developed a symptomatic, nonfatal PE. More than 80% of the DVTs were distal and all were detected within 2 weeks of surgery.