Perioperative allogenic blood transfusions are associated with increased fracture related infection rates, but not nonunion in operatively treated distal femur fractures.

• Distal femur fractures remain difficult injuries to effectively treat with this study observing a fracture related infection (FRI) rate of 8% and nonunion rate of 13%. • Allogenic blood transfusions were not associated with patients developing a nonunion. (P = 0.91). • Allogenic blood transfusions were associated with FRI (P <0.001) and the association increased in a dose-dependent manner with increasing blood transfusions. Distal femur fractures are common injuries that remain difficult for orthopedic surgeons to treat. High complication rates, including nonunion rates as high as 24% and infection rates of 8%, can lead to increased morbidity for these patients. Allogenic blood transfusions have previously been identified as risk factors for infection in total joint arthroplasty and spinal fusion surgeries. No studies have explored the relationship between blood transfusions and fracture related infection (FRI) or nonunion in distal femur fractures. 418 patients with operatively treated distal femur fractures at two level I trauma centers were retrospectively reviewed. Patient demographics were collected including age, gender, BMI, medical comorbidities, and smoking. Injury and treatment information was also collected including open fracture, polytrauma status, implant, perioperative transfusions, FRI, and nonunion. Patients with less than three months of follow up were excluded. 366 patients were included in final analysis. One hundred thirty-nine (38%) patients received a perioperative blood transfusion. Forty-seven (13%) nonunions and 30 (8%) FRI were identified. Allogenic blood transfusion was not associated with nonunion (13% vs 12%, P = 0.87), but was associated with FRI (15% vs 4%, P <0.001). Binary logistic regression analysis identified a dose dependent relationship between number of perioperative blood transfusions and FRI: total transfusion ≥2 U PRBC RR= 3.47(1.29, 8.10, P = 0.02), ≥3 RR= 6.99 (3.01, 12.40, P <0.001), and ≥4 RR= 8.94 (4.03, 14.42, P <0.001). In patients undergoing operative treatment of distal femur fractures, perioperative blood transfusions are associated with increased risk of fracture related infection, but not the development of a nonunion. This risk association increases in a dose-dependent relationship with increasing total blood transfusions received. [ABSTRACT FROM AUTHOR]