Acute Hematogenous Osteomyelitis of the Pelvis in Children.

Background: Pelvic involvement has been reported in 3%-14% of acute hematogenous osteomyelitis (AHO) cases in children. One guideline suggests need for a longer antibiotic course in pelvic AHO, however, recent data are lacking. We describe the clinical course of children with pelvic AHO and compare it to nonpelvic AHO. Methods: A retrospective review of patients with a diagnosis of AHO admitted to Texas Children's Hospital from January 2012 to December 2020 was conducted. Patients 6 months-<19 years old and with <= 14 days of symptoms at admission were eligible. Patients with sickle cell disease or immunocompromised were excluded. Wilcoxon rank-sum test assessed for differences between continuous variables and Fisher exact for categorical variables using STATA 17. Results: We compared 104 cases of pelvic AHO to 314 cases of nonpelvic AHO. Patients had similar microbiology, length of stay and length of antibiotic therapy. Patients with pelvic AHO had pyomyositis identified by magnetic resonance imaging more often (28.8 vs. 9.4%, P < 0.001) and bone abscess less often (22.1 vs. 46.5%, P < 0.001). Rates of chronic complications were comparable between patients with pelvic AHO and nonpelvic AHO (8.4% vs. 15.1%, P = 0.1). Nineteen patients (18.3%) with pelvic AHO received <= 30 antibiotic days without complications, but they had less need for intensive care or bone abscesses than patients treated longer. Conclusions: Pelvic AHO in children may be more frequent than previously reported but is not associated with more complications. Four weeks of therapy may be sufficient in selected patients. Prospective studies to compare outcomes with different lengths of therapy are needed.