Adverse outcomes in hip arthroplasty: long-term trends.

BACKGROUND: Total hip arthroplasty is a common surgical procedure, but little is known about longitudinal trends in associated adverse outcomes. Our objective was to describe long-term trends in demographics, comorbidities, and adverse outcomes for older patients who underwent primary and revision total hip arthroplasty.
METHODS: We identified a retrospective, observational cohort of 1,405,379 Medicare beneficiaries who underwent primary total hip arthroplasty and 337,874 who underwent revision total hip arthroplasty between 1991 and 2008. The primary outcome was a composite representing the occurrence of one or more of the following adverse outcomes during the index admission or during readmission within ninety days after discharge: death, hemorrhage, infection, pulmonary embolism, sepsis, deep venous thrombosis, and myocardial infarction. Secondary outcomes included each of these outcomes assessed individually.
RESULTS: Between 1991 and 2008, the mean age and the mean comorbidity burden increased for all total hip arthroplasty patients. The length of hospital stay after primary and revision total hip arthroplasty declined by approximately 50% over the study period. However, the rate of readmission for any cause has recently increased and has surpassed 10% for primary total hip arthroplasty and 20% for revision total hip arthroplasty. The composite rate of adverse outcomes after primary total hip arthroplasty declined from 4% to 3.4% over the study period, whereas the composite adverse outcome rate after revision total hip arthroplasty slowly increased from 7% to 10.9%. We observed a steady decline in the rates of most individual adverse outcomes after primary total hip arthroplasty over the majority of the study period. Many of these rates stabilized or began to increase slightly near the end of the study period. In contrast, an increase in the rates of many adverse outcomes was observed in the revision total hip arthroplasty population even after accounting for changes in patient complexity. Postoperative hemorrhage has gradually increased after both primary and revision total hip arthroplasty.
CONCLUSIONS: Patients undergoing primary and revision total hip arthroplasty are becoming more complex. Despite this increasing complexity, patient outcomes for primary total hip arthroplasty improved markedly before stabilizing in recent years. In contrast, patient outcomes after revision total hip arthroplasty have gradually worsened, likely reflecting the increase in the medical comorbidities and surgical complexity of these patients. Length of hospital stay has demonstrated a substantial decline, which has recently been coupled with an increased readmission rate. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.