Patellar Subacute Hematogenous Osteomyelitis in Children Due To K. Kingae: A Report of Two Cases

Isolated osteomyelitis of the patella is a rare condition mainly occurring in the pediatric population. Diagnosis is often delayed as clinical presentation manifests with vague anterior knee pain, sometimes with mild local signs of inflammation but frequently without any local signs at all. While falls on the knee can explain mild knee pain, erythema, swelling and persistent peripatellar pain should raise a high index of suspicion for local infection. We present two cases of subacute osteomyelitis of the patella in young children. In both cases bone lesions presented as an osteolytic lesion of the patella. After open biopsy of the lesion, bacteriological analysis confirmed infection with Kingella kingae.