Limb-Sparing Reconstruction for Chronic Non-Bacterial Osteomyelitis of the Toe in a Pediatric Athlete: A Case Report

<b>Background and Clinical Significance:</b> Chronic non-bacterial osteomyelitis (CNO) is a rare autoinflammatory bone disorder that primarily affects children and adolescents, with females more frequently impacted. The condition remains poorly understood, though cytokine dysregulation and inflammasome activation are believed to contribute to its pathogenesis. Clinically, CNO is often difficult to distinguish from infectious osteomyelitis, as presenting symptoms such as bone pain, swelling, and functional limitation are nonspecific, while cultures are frequently negative. As a diagnosis of exclusion, delays in recognition can lead to prolonged or unnecessary antibiotic exposure and uncertainty in management. <b>Case Presentation:</b> A 14-year-old male with a history of left second toe osteomyelitis initially diagnosed in 2021. Despite negative cultures and limited histopathologic findings, he received multiple antibiotic courses with little improvement, and the digit remained chronically swollen. Three years later, a repeat evaluation revealed osseous resorption of the middle and distal phalanges, and a biopsy confirmed acute and mild chronic fibrosing osteomyelitis, consistent with CNO. Given the risk of progression and possible amputation, surgical reconstruction was pursued. The patient underwent autologous calcaneal bone grafting with digital fusion using a K-wire. At three months and one year postoperatively, radiographs demonstrated solid fusion of the digit with maintained activity and resolution of pain. <b>Conclusions:</b> This case emphasizes the diagnostic complexity of CNO and the importance of considering it in children with culture-negative or recurrent osteomyelitis. It further illustrates how timely surgical intervention can preserve function and quality of life while avoiding unnecessary amputation.