Pathologic Fracture Secondary to Acute Hematogenous Osteomyelitis in Children in New Zealand

BACKGROUND: Acute hematogenous osteomyelitis is a common pediatric musculoskeletal infection that has been well studied in the literature. Moderate to severe cases of osteomyelitis may weaken and destabilize the bone architecture leading to complications like pathologic fracture. The purpose of this study was to investigate the risk factors for the development of pathologic fracture following acute hematogenous osteomyelitis for children in New Zealand. METHODS: Nine patients who were treated for a pathologic long-bone fracture secondary to Staphylococcus aureus osteomyelitis between January 2009 to December 2019 at the Starship Children's Hospital in Auckland, New Zealand were identified. These patients were compared with a age and sex matched control group of twenty-seven children with Staphylococcus aureus osteomyelitis without a pathologic fracture. A retrospective review of patient's clinical records, lab and microbiological findings was performed. RESULTS: Patients who developed a fracture presented with osteomyelitis at a mean age of 5.3 years (range, 0.1 to 8.6 years). The mean time from initial osteomyelitis onset to pathologic fracture was 49 days (range, nine to 116 days). Patients with an increased NZ deprivation score and those of Pacific-Islander ethnicity differed significantly between the two groups. For initial clinical presentation, it was found that swelling, reduced range of motion and erythema, and higher CRP levels showed significant differences between the two groups. Length of stay, PICU admission and increased readmissions also showed significant differences between the two groups. The management strategy of the pathologic fracture group was also presented. CONCLUSIONS: Patients presenting with more severe acute infections are at significant risk of pathologic fracture following osteomyelitis. Prophylactic treatment plans such as early immobilization and casting may be necessary in patients presenting with these risk factors to prevent the long and difficult treatment of pathologic fracture.