Complications of Total Hip Arthroplasty in Patients With Ankylosing Spondylitis

Objective 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 data from 1999 to 2013 of US Medicare beneficiaries (ages <75 years old) with AS and a comparison group without AS who had undergone primary THA. Complications were based on the Centers for Medicare & Medicaid Services 2013 THA Complication Measure, which included myocardial infarction, pneumonia, or sepsis within 7 days; surgical site bleeding, pulmonary embolus, or venous thrombosis within 30 days; or mechanical complications or local infection within 90 days. Mortality within 90 days, revision arthroplasty within 1 year, long length of stay, discharge to a care facility, and readmission within 90 days were also examined. Results The study included 2,773 patients with AS and 107,341 patients without AS who had THA. Perioperative complications, 30-day complications, and local infections were rare in both groups (<1%). Mechanical complications and revision arthroplasty were uncommon in both groups. Ninety-day mortality was lower among patients with AS than those without 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 THAs per year, but other complications were not associated with hospital volume. Conclusion 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.