Pulmonary Embolism After Knee Arthroscopy: Rare But Serious

Study outlines likelihood and risk factors; females more than thirty years of age affected

SAN DIEGO, Feb. 18, 2011 /PRNewswire-USNewswire/ -- Until now, the risk of pulmonary embolism (PE) after a knee arthroscopy has not been accurately defined and risk factors have only been suggested but not proven.  New research, presented today at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) shows that the incidence of symptomatic PE after outpatient knee arthroscopy is .028 percent.  Researchers also indentified risk factors including age, increased operating time, female gender and history of cancer.

"We anticipated 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 Iftach Hetsroni, MD, study author and orthopaedic surgeon, Department of Orthopedic Surgery, Meir General Hospital, Kfar Saba, Israel.

The study, performed at Hospital for Special Surgery, New York, examined data on 374,033 patients undergoing 418,323 outpatient arthroscopic knee procedures between 1997 and 2006 as recorded in the New York State Department of Health Statewide Planning and Research Cooperative System administrative database.  Cases were defined as hospital readmission within 90 days of arthroscopic procedure with a diagnosis of PE.  There were 117 PE cases (.028 percent) with one reported death.

The study identified several risk factors:

• Patients 30 years and older are six times more at risk than patients younger than twenty years.
• Operating room time greater than 90 minutes is associated with three times more risk compared to procedures less than 30 minutes.
• Females are 1.5 times more at risk than males.
• History of cancer is associated with three times more risk.

Anesthesia type, complexity of surgery (i.e. reconstruction of the anterior cruciate ligament or meniscus repair as compared to simple meniscectomy), or other existing conditions were not proven to increase a patient's risk of PE.

"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 Dr. Hetsroni. "For example, our study may encourage some surgeons to consider thromboprophylaxis, or blood-thinning techniques, for patients who have multiple risk factors."

Patients should watch for several complications and warning signs and seek medical care immediately if they are experiencing any PE symptoms such as chest discomfort or palpitations.  Most PEs occur seven to 10 days after surgery and typically prior to three months post surgery.

"Athletes should understand that while a pulmonary embolism after knee arthroscopy is extremely rare, it can happen and lead to serious complications," said Dr. Hetsroni.

More about knee arthroscopy and PE:

More than 4 million knee arthroscopies are performed worldwide each year according to the American Orthopaedic Society for Sports Medicine.  

Arthroscopy is a common surgical procedure in which a joint (arthro-) is viewed (-scopy) using a small camera.  Arthroscopy gives doctors a clear view of the inside of the knee. It helps him or her diagnose and treat knee problems such as torn cartilage, torn ligaments and inflamed tissue.

Pulmonary embolisms occur when blockage, such as a clot, travels from elsewhere in the body to the lungs.  The obstruction of the blood flow through the lungs puts pressure on the heart which leads to the symptoms and signs of PE.  These symptoms include difficulty breathing, chest pain and palpitations.  Severe cases of PE can lead to death.

Disclosure: Dr. Hetsroni received no compensation for this study

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SOURCE American Academy of Orthopaedic Surgeons