Isolated congenital pseudarthrosis of the fibula: A case report

Abstract

Introduction: Congenital pseudarthrosis of the fibula (CPF) is an uncommon entity, representing less than 1% of all congenital pseudarthroses of the lower limb. It may occur in isolation or in association with congenital pseudarthrosis of the tibia and neurofibromatosis type 1 (NF1). The pathophysiology involves periosteal and vascular alterations that impair osteogenesis, resulting in atrophic nonunion and progressive ankle valgus deformity. Early diagnosis and long-term follow-up are crucial to prevent angular progression and instability.

Case Presentation: A 4-year-old boy presented with progressive valgus deformity of the left ankle, without pain or history of significant trauma. Radiographs demonstrated a hypoplastic fibula with an isolated distal pseudarthrosis and a lateral distal tibial angle (LDTA) of 66°. The patient underwent corrective osteotomy of the fibula, placement of an allogeneic bone graft, and internal fixation with an anatomic locking plate. Immediate postoperative correction achieved an LDTA of 87°. At the 60-month follow-up, the patient remained asymptomatic, with no evidence of refracture or recurrence of the deformity.

Conclusion: Isolated congenital pseudarthrosis of the fibula is an exceptionally rare condition. Surgical correction through stable fixation and bone grafting can achieve long-lasting union and correction of deformity. This case demonstrates that early reconstruction and structured long-term follow-up can result in durable functional and radiographic outcomes.