Young age, osteomyelitis, pyogenic bacterial isolation predict sequelae in septic arthritis

Young age, pyogenic bacterial isolation, and concomitant osteomyelitis are associated with a high risk of sequelae in septic arthritis (SA), according to a Singapore study.

“Timely microbiologic diagnosis by novel polymerase chain reaction methods and the use of magnetic resonance imaging in high-risk children to identify adjacent infection could possibly prevent lifelong disabling sequelae in SA,” the researchers said. “Furthermore, a cautious and conservative approach to the duration of antibiotic use is required in high-risk children.”

Discharge and laboratory records were used to identify patients with bacteriologically or radiologically confirmed SA from January 1999 to December 2014. A retrospective review of the case notes was carried out for the data collection.

Seventy-five patients (median age at presentation, 6 years; range, 2 weeks to 15 years; 62.7 percent male) were included in the analysis, of whom six were neonates. [Singapore Med J 2020;doi:10.11622/smedj.2020140]

Of the patients, 40 (53.3 percent) had their microbiologic aetiology determined; the most common organism found was Staphylococcus aureus. In addition, 68 percent of the patients underwent arthrotomy, with an average hospital stay of 15.3 days.

On follow-up, nine patients had sequelae of SA. In univariate and multivariate statistical analyses, sequelae development was significantly predicted by the following factors: young age, pyogenic bacterial isolation, and concomitant osteomyelitis.

“Our study demonstrated that young age, pyogenic bacterial isolation, and concomitant osteomyelitis were associated with a high risk of sequelae,” the researchers said. “We opine that prompt recognition and aggressive management of children at high risk of developing sequelae could possibly improve the long-term outcome.”

Several studies have established young age as a significant predictor for poor prognosis in SA. In addition, infants have a higher rate of coexisting oeteomyelitis and SA due to the enhanced spread of infection from the metaphysis to the joint caused by the unique transphyseal vasculature in this age group. [Pediatr Rev 2011;32:470-480; J Bone Joint Surg Br 2009;91:1127-1133; J Microbiol Immunol Infect 2003;36:41-46; J Pediatr Orthop B 2013;22:486-490]

In a 2014 study, Ceroni and colleagues stressed the importance of timely diagnosis alongside prompt and aggressive antimicrobial therapy and surgical irrigation in ensuring a good prognosis for SA. [Swiss Med Wkly 2014;144:w13971]

The gold-standard treatment for SA of tightly encapsulated joints, such as the hip and shoulder, is open arthrotomy, particularly for the rapid reduction of intra-articular pressure to prevent avascular necrosis. However, less invasive procedures such as arthroscopy and serial ultrasonography-guided aspirations have shown favourable results. [Arch Dis Child 2012;97:287-292; J Child Orthop 2008;2:229-237]

“Currently, there is insufficient evidence for the routine use of dexamethasone as adjuvant therapy,” the researchers noted. “Further prospective studies addressing the risk factors for developing sequelae in SA are needed to improve long-term outcome.”