Primary Hip and Knee Arthroplasty in a Safety Net Hospital: Substance Abuse and Other Factors Affecting Short-term Complications

Background: Arthroplasty outcomes and patient risk factors have not been studied in detail in safety net hospital settings. This study examines the relationship between selected risk factors and short-term complications in such a population, including a large subgroup with treated substance abuse. Methods: This retrospective cohort study contains 486 consecutive patients after primary hip and knee arthroplasty. One hundred three of these had a history of substance abuse and completed a 1-year sobriety pathway preoperatively. Primary outcomes included the presence of any complication, deep infection, and reoperation. Bivariable analyses were used to compare outcomes with demographic and health risk factors. A multivariate analysis was performed to identify independent risk factors. Results: Adverse outcomes were more common in patients with higher rates of substance abuse, mental illness, and infection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). Substance abuse alone was not an independent risk factor for the occurrence of complications, but infections with HIV and HCV were. In the substance abuse subgroup, with its higher prevalence of risk factors, complications were more frequent (31.1% vs 16.4%, P =.0009), and, in particular, deep infections (5.8% vs 1.8%, P =.0256). Conclusions: Specific risk factors were associated with short-term complications in safety net arthroplasty patients. Despite having completed a preoperative sobriety pathway, substance abuse patients had more complications than did others. However, substance abuse alone was not an independent risk factor for adverse surgical outcomes. Other factors, notably HCV and HIV infection that were more common in patients with substance abuse, were most closely associated with adverse outcomes.