Septic Arthritis Among Users of Injection Drugs: Clinical Course and Microbial Characteristics.

Abstract

Injection drug use (IDU) is a risk factor for septic arthritis (SA) of native joints. Amid the opioid crisis, IDU rates have increased. This study assessed differences in pre-operative characteristics, microbial characteristics, and postoperative outcomes of 177 cases of SA treated operatively from 2015 to 2019 at 3 US hospitals, by self-reported IDU status. Forty cases (23%) involved patients who reported IDU. Patient characteristics, comorbidities, microbial characteristics, duration of hospital stay, discharge destination, follow-up rates, and rates of persistent/secondary infection were compared by self-reported IDU status. Compared with non-IDU-associated SA (non-IDU-SA), IDU-associated SA (IDU-SA) was associated with female sex (<i>P</i>=.001), younger age (<i>P</i><.001), lower body mass index (<i>P</i><.001), tobacco use (<i>P</i><.001), and psychiatric diagnosis (<i>P</i>=.04) and was more likely to involve methicillin-resistant <i>Staphylococcus aureus</i> (<i>P</i><.001). The IDU-SA was associated with discharge to a skilled nursing facility or against medical advice (<i>P</i><.001) and with loss to follow-up (<i>P</i>=.01). The 2 groups did not differ in terms of American Society of Anesthesiologists classification, joint involved, Gram stain positivity, presence of bacteremia, peripherally inserted central catheter placement, return to hospital within 3 months, or persistent/secondary positive results on culture within 3 months. Patients with IDU-SA were younger, were more likely to be female, had lower body mass index, and had fewer medical comorbidities but were more likely to use tobacco and to have a psychiatric diagnosis compared with patients with non-IDU-SA. Methicillin-resistant <i>S aureus</i> was more common in the IDU-SA group, as was discharge to a skilled nursing facility or against medical advice. Patients with IDU-SA were less likely to return for follow-up than patients with non-IDU-SA. [<i>Orthopedics</i>. 2021;44(6):e747-e752.].