Abstract
Purpose of the study: The aim of this study was to determine risk factors for clinically relevant pulmonary embolism (PE) in patients undergoing elective knee arthroplasty.
Methods and results: We performed a retrospective analysis of 956 total knee arthroplasties performed at our institution between June 2007 and May 2008 to identify patients with postoperative PE confirmed by computed tomography pulmonary angiogram (CTPA). All patients had received foot pumps, thromboembolism deterrent stockings and 75mg of Aspirin postoperatively. Patients with PE were matched for age, gender, surgeon, date and type of surgery with a control group of 32 patients. Patients case notes were reviewed to identify known risk factors for PE such as age, gender, ASA grade, BMI, medical comorbidities, pre-operative haemoglobin (Hb), postoperative Hb, drop in Hb, day mobilised postoperatively, tourniquet time and temperature in the postoperative period. Statistical analysis was performed using Statistical Package for the Social Sciences version 12.0 (SPSS Inc., Chicago, Illinos).
Twenty one (2.2 %) cases were identified with CTPA confirmed PE. Of the various risk factors studied, delay in postoperative mobilization was the only significant risk factor for PE (p=0.019). None of the other risk factors were significant for PE. Postoperative pain was the commonest reason for delayed mobilisation followed by lower limb paraesthesia from regional nerve blocks.
Conclusion: We found that a delay in postoperative mobilization was the most significant risk factor for clinically relevant PE in our patient population following knee arthroplasty. The use of chemical thromboprophylaxis for all patients undergoing elective knee arthroplasty is currently under debate. Not all patients are at equal risk, however, and chemical prophylaxis is not devoid of complications. Early postoperative mobilization of all patients may help prevent this potentially fatal complication.
Correspondence should be addressed to: BASK c/o BOA, at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London, WC2A 3PE, England.
