Aneurysmal Bone Cyst of the Distal Femoral Metaphysis in a Three-Year-Old Male Patient Presenting With a Pathologic Fracture: A Case Report.

This case report discusses the management of a three-year-old male presenting with a pathological fracture of the distal femur due to an aneurysmal bone cyst (ABC). Due to diagnostic uncertainty and limited resources, the treatment involved an en bloc resection followed by the Masquelet technique with a fibular and cancellous graft. While this approach successfully reconstructed the bone defect, the patient developed a progressive valgus deformity and limb length discrepancy, likely due to physeal damage from the resection rather than the reconstruction technique itself. This case highlights the challenges of balancing recurrence risk, functional outcomes, and resource limitations in pediatric ABC treatment. A more physeal-sparing approach, such as curettage with bone grafting, might have mitigated complications while preserving long-term limb function.