Knee surgery rarely leads to pulmonary embolism
MedWire News: Symptomatic pulmonary embolism (PE) is extremely rare after knee arthroscopy, show study results presented this week at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons in San Diego, California, USA.
Nevertheless, the researchers identified age over 30 years, operating time over 90 minutes, female gender, and history of cancer as factors that may increase the risk for PE up to sixfold in patients undergoing this operation.
"We anticipated [that] the incidence of PE after knee arthroscopies would be low but we wanted to uncover exactly what risk patients were undergoing and who might be at increased risk," said study author Iftach Hetsroni (Meir General Hospital, Kfar Saba, Israel).
Hetsroni and team searched the New York State Department of Health's administrative database and identified 374,033 patients who underwent 418,323 arthroscopic knee procedures between 1997 and 2006.
In total, 177 cases of PE were diagnosed within 90 days of surgery, giving a PE incidence rate of 0.028% or 2.8 cases per 10,000 operations.
The researchers say that the low PE incidence may be due to the limited extent of soft tissue injury, blood vessel compression, and bony trauma that occurred during the majority of these procedures, as well as the relatively limited postoperative immobilization prescribed after these operations.
When the team looked at risk factors for PE they found that patients over 30 years of age had a significant six-fold greater risk for PE than those aged below 20 years.
Longer operating time was also associated with a greater PE risk, with procedures lasting longer than 90 minutes conferring a three-fold greater risk for PE than those lasting under 30 minutes.
In addition, women were 1.5 times more likely than men to have PE, and patients with a history of cancer were three times more likely to experience PE than those with no cancer history.
Conversely, anesthesia type, complexity of surgery, and co-morbidity score were not linked to an increased PE risk.
"While knee arthroscopy performed as an outpatient seems like an innocent procedure, patients with one or more of these risk factors should talk with their doctors about any precautions before or after surgery," explained Hetsroni.
"For example, our study may encourage some surgeons to consider thromboprophylaxis, or blood-thinning techniques, for patients who have multiple risk factors," he concluded.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Laura Dean