Avascular necrosis is associated with increased transfusions and readmission following primary total hip arthroplasty

Avascular necrosis (AVN) may confer an increased risk of complications and readmission following total hip arthroplasty (THA). However, current risk-adjustment models do not account for AVN. A total of 1706 patients who underwent THA for AVN from 2011 to 2013 were selected from the American College of Surgeon's National Surgical Quality Improvement Program database and matched 1:1 to controls using a predetermined propensity score algorithm. Rates of 30-day medical and surgical complications, readmissions, and reoperations were compared between cohorts. Propensity-score logistic regression was used to determine independent associations between AVN and outcomes of interest. Patients with AVN had a higher rate of medical complications than those without AVN (20.3% vs 15.3%, respectively; P<.001). Bleeding transfusion was the most common medical complication, occurring at a significantly higher rate in patients with AVN than those without AVN (19.6% vs 13.9%, respectively; P<.001). Patients with AVN were also twice as likely to experience a readmission after THA (odds ratio, 2.093; 95% confidence interval, 1.385-3.164). Avascular necrosis of the femoral head is an independent risk factor for transfusion up to 72 hours postoperatively and readmission up to 30 days following total hip replacement.