Conflicting results about the impact of blood transfusions on outcomes after total knee arthroplasty (TKA) have been reported. We hypothesized that transfusions would be associated with greater readmission and complication rates after primary TKA. We conducted a retrospective cohort study of the 100% 2008 Medicare Provider Analysis and Review database, and identified primary THA patients by ICD9 codes and excluded fractures/ER admissions to select for elective cases. Patients who received a perioperative blood transfusion (6,951 patients) were compared to a control group who did not receive transfusion (332,762 patients). Descriptive statistics of age, sex, race, diagnosis for surgery, Elixhauser comorbidities, mortality (inpatient, 30, 60, and 90 days and 2 years), readmissions (30, 60, and 90 days), complications (medical and surgical at 30 and 90 days), and revision at 2 years were assessed for both groups. Continuous variables were compared with Student's T-test and categorical variables with chi-square test. Multivariate logistic regression models were constructed to assess the association of transfusion with readmissions, complications, and revisions. Statistical significance was set at p < 0.01.Background
Methods
1. The hypothesis is advanced that the fundamental lesion of epiphysiolysis is a slow posterior growth migration of the head on the neck. 2. It is suggested that this is unrelated to the erect posture or to any abnormality of the growth cartilage. 3. Sitting stresses are measured and are postulated as the likely cause of the growth deviation. 4. The result of the deviation is an increase in the shear stress component; in the erect posture clinical epiphysiolysis is regarded as a simple fracture occurring in a proportion of deviated cases when the increased shear component exceeds the critical level appropriate to the individual. 5. It is suggested that this hypothesis explains the age and sex incidence, the left predominance, the reduced epiphysial angle found on the uninvolved hip and the clinical and radiological evolution of the disorder.
