Development and Validation of a Risk Stratification System for Pulmonary Embolism After Elective Primary Total Joint Arthroplasty.

INTRODUCTION: Stratification of patients into different risk categories for pulmonary embolism (PE) after total joint arthroplasty (TJA) may allow clinicians to individualize venous thromboembolism prophylaxis based on an appropriate risk-benefit scale.

METHODS: Patients undergoing primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) as part of the American College of Surgeons National Surgical Quality Improvement Program were identified. Independent risk factors for PE within 30 days of surgery were identified and used to develop a point-scoring system to estimate the relative risk for PE. For validation, the system was tested on patients undergoing TJA at a single institution.

RESULTS: A total of 118,473 patients were identified, including 72,673 (61.3%) undergoing TKA and 45,800 (38.7%) undergoing THA. The incidence of PE within 30 days of the index arthroplasty was 0.50%. The risk factors associated with PE were age ≥70, female gender, higher body mass index (25-30 kg/m(2) and ≥30 kg/m(2)), and TKA (vs THA); anemia was protective. The point scores derived for each of these factors were as follows: anemia: -2; female: +1; body mass index 25-30 kg/m(2): +2; body mass index ≥30 kg/m(2): +3; age ≥70 years: +3; TKA: +5. The point-scoring system was then applied to 17,384 patients from a single institution. Single-institution patients categorized as low risk using the point-scoring system had a 0.44% 90-day risk for PE (95% CI = 0.29%-0.58%); medium risk, 1.51% (95% CI = 1.18%-1.84%); and high risk, 2.60% (95% CI = 2.09%-3.10%).

CONCLUSION: This point-scoring system predicts risk for PE after TJA and may help surgeons to optimize selection of chemical prophylaxis.