Complications of total hip arthroplasty in patients with ankylosing spondylitis.

BACKGROUND: To compare the risks of complications of primary total hip arthroplasty (THA) between patients with ankylosing spondylitis (AS) and those without AS.

METHODS: In this population-based study, we examined U.S. Medicare beneficiaries (< 75 years old) with AS and a comparison group without AS who had primary THA in 1999 - 2013. Complications were based on the 2013 Centers for Medicare & Medicaid Services THA Complication Measure, which included myocardial infarction, pneumonia, and sepsis within 7 days; surgical site bleeding, pulmonary embolus, or venous thrombosis within 30 days; and mechanical complications or local infection within 90 days. In addition, mortality within 90 days, revision arthroplasty within one year, long length of stay, discharge to a care facility, and readmission within 90 days were examined.

RESULTS: The study included 2773 patients with AS and 107,341 patients without AS who had THA. Perioperative, 30-day complications, and local infections were rare (< 1%) in both groups. Mechanical complications and revision arthroplasty were uncommon in both groups. Ninety-day mortality was lower among patients with AS (0.36% versus 0.7%). Patients with AS were more likely to be discharged to a care facility, and slightly more likely to have a long length of stay. Likelihood of a long stay was lower at hospitals that performed ≥ 100 THA per year, but other complications were not associated with hospital volume.

CONCLUSIONS: Complications after primary THA are uncommon in patients with AS and similar in frequency to those without AS. Ninety-day mortality was lower among patients with AS. This article is protected by copyright. All rights reserved.