Treatment of cases of congenital pseudarthrosis of the fibula presenting with severe or progressive valgus deformity in early childhood is challenging. The purpose of the study presented was to analyse the deforming mechanisms to get therapeutic recommendations for this condition. A 2.5-year-old child was treated by resection of pseudarthrosis and distal tibiofibular fusion (Langenskiold operation) with autogenous bone grafting, associated with subtalar arthroereisis: progressive correction of the deformity was achieved. A 21-month-old child was treated with resection of pseudarthrosis, homologous bone grafting and fibular osteosynthesis: after failure, Langenskiold operation with autogenous bone grafting was performed and stabilization of the deformity was achieved. In young children with congenital pseudarthrosis of the fibula and valgus deformity, early surgical treatment is advisable: fibular ostheosynthesis has limited indications; distal tibiofibular fusion remains the treatment of choice, providing correction that may exceed the simple stabilization of deformity expected. Radiographic findings lead the authors to suggest that part of the effectiveness of the procedure is due to abnormal growth patterns.