Risk factors, causes, and the economic implications of unplanned readmissions following total hip arthroplasty.

In order to identify risk factors for readmissions following total hip arthroplasty (THA) and the causes and financial implications of such readmissions, we analyzed clinical and administrative data on 1583 consecutive primary THAs performed at a single institution. The 30-day readmission rate was 6.51%. Increased age, length of stay, and body mass index were associated with significantly higher readmission rates. The most common re-admitting diagnoses were deep infection, pain, and hematoma. Average profit was lower for episodes of care with readmissions ($1548 vs. $2872, P=0.028). If Medicare stops reimbursing for THA readmissions, the institution under review would sustain an average net loss of $11,494 for episodes of care with readmissions and would need to maintain readmission rates below 23.6% in order to remain profitable.