Prevalence of Complications Due to Transphyseal Hematogenous Osteomyelitis.

BACKGROUND Transphyseal hematogenous osteomyelitis (THO) is a common infectious condition, being present in 25% of patients with hematogenous osteomyelitis. A large proportion of pediatric hematogenous osteomyelitis infections can spread through the growth cartilage and therefore may be potentially responsible for growth disorders, leading to limb-length discrepancy or angular deformities. The purpose of the present study was to identify both the prevalence of complications caused by transphyseal osteomyelitis and factors influencing their occurrence. METHODS The records for all patients who had been treated for THO over a 17-year period at the University Hospitals of Geneva and the Gesù Bambino Hospital in Rome were retrospectively analyzed. Clinical, biological, and bacteriological data were analyzed. Magnetic resonance imaging (MRI) scans were reviewed for all patients to assess the cross-sectional area of growth plate involvement. Restart of growth of the affected physeal cartilage was subsequently monitored by means of iterative radiographic examination. RESULTS From a cohort of 594 patients with hematogenous osteomyelitis, 89 patients (15.0%) were found to have THO. The median age was 84 months (range, 1 to 167 months), with a bimodal distribution and peaks at 30 and 150 months; 59.6% (53) of the 89 patients were male. The lower limbs were most often affected, with the distal tibia and fibula accounting for 47.2% of all cases. Methicillin-sensitive Staphylococcus aureus and Kingella kingae were the most frequently identified pathogens, accounting for 61.8% of the cases. Virulence factors, such as Panton-Valentine leukocidin (PVL), toxic shock syndrome toxin (TSST), and accessory gene regulator (Agr), were recorded in 12.4% of MSSA strains. Transphyseal lesions affected a median of 7.6% (range, 0.79% to 58.2%) of the physeal surface. Complications affecting further growth were noted in 13% of patients with THO. Thrombocytopenia, leukocytosis, and the presence of virulence factors significantly influenced the occurrence of complications. CONCLUSIONS THO affects all age categories of the pediatric population. In the present study, growth disturbance occurred in 13% of cases. The presence of deep thrombocytopenia, leukocytosis, and virulence factors, such as Agr, TSST, and PVL, seems to strongly influence the occurrence of such complications. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.