title: Impact of perioperative allogeneic and autologous blood transfusion on acute wound infection following total knee and total hip arthroplasty.
abstract: BACKGROUND
  Patients undergoing total hip or knee arthroplasty frequently receive blood transfusions. The relationship between transfusion and the risk of infection following total joint arthroplasty is unclear. In this study, we sought to examine the impact of allogeneic and autologous transfusion on the risk of acute infection following total hip and total knee arthroplasty.
  
  
  METHODS
  We performed a retrospective study of consecutive primary total knee arthroplasties and total hip arthroplasties. Patients who had a reoperation for suspected infection within three months after the arthroplasty were identified. Differences in risk factors were assessed across transfusion groups: no transfusion, autologous only, and allogeneic exposure (allogeneic with or without additional autologous transfusion). Backward-stepwise logistic regression analysis was used to compare reoperations (as outcomes) between cases with and those without allogeneic exposure. Prespecified covariates were body mass index, diabetes, an American Society of Anesthesiologists (ASA) score of >2, preoperative hematocrit, and total number of units transfused perioperatively.
  
  
  RESULTS
  We identified 3352 patients treated with a total hip or knee arthroplasty (1730 total knee arthroplasties and 1622 total hip arthroplasties) for inclusion in the study. Transfusion was given in 1746 cases: 836 of them had allogeneic exposure, and 910 had autologous-only transfusion. There were thirty-two reoperations (0.95%) for suspected infection. Between-group risk-factor differences were observed. The mean age and the rates of diabetes, immunosuppression, ASA scores of >2, and bilateral surgery were highest in the allogeneic group, as were estimated blood loss, surgery duration, and total number of units transfused (p < 0.001). In the unadjusted analyses, the rate of reoperations for suspected infection was higher in the cases with allogeneic exposure (1.67%) than in those without allogeneic exposure (0.72%) (p = 0.013). Autologous-only transfusion was not associated with a higher reoperation rate. However, multivariable logistic regression demonstrated that the total number of units transfused (p = 0.011) and an ASA score of >2 (p = 0.008)-but not allogeneic exposure-were significantly predictive of a reoperation.
  
  
  CONCLUSIONS
  Perioperative allogeneic transfusion was associated with a higher rate of reoperations for suspected acute infection. However, patients with allogeneic exposure had increased infection risk factors. After adjustment for the total number of units transfused and an ASA score of >2, allogeneic exposure was not significantly predictive of a reoperation for infection.
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: Erik T
authors.initials: ET
authors.lastname: Newman
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: Tyler Steven
authors.initials: TS
authors.lastname: Watters
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: John S
authors.initials: JS
authors.lastname: Lewis
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Jennings
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Wellman
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: David E
authors.initials: DE
authors.lastname: Attarian
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Grant
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Green
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco Medical Center, San Francisco, CA 94143.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Vail
authors.affiliation: Department of Orthopaedic Surgery (E.T.N., T.S.W., J.S.L., J.M.J., S.S.W., D.E.A., and M.P.B.), Anesthesiology (S.A.G.), and Biostatistics and Bioinformatics (C.L.G.), Duke University Medical Center, Durham, NC 27710. E-mail address for T.S. Watters: tyle.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Bolognesi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D001803:Blood Transfusion / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D013530:Surgical Wound Infection / Q000209:etiology*; D016896:Treatment Outcome