Congenital pseudarthrosis of the tibia.

Congenital pseudarthrosis of the tibia (CPT) is an uncommon disease with various clinical presentations ranging from simple anterolateral tibial angulation to complete non-union with extensive bone defects. Classifications of radiographic findings include atrophic or hypertrophic pseudarthosis as well as cystic or dystrophic lesions. Although the relationship between CPT and type 1 neurofibromatosis is well known, the exact pathogenesis still remains unclear. The fibrous soft tissue found in the pseudarthosis and the abnormal periosteum are certainly a key to the pathology, possibly due to decreased osteogenic capacities and impaired local vascularization. Treatment of CPT is still challenging in pediatric orthopedics because of bone union difficulties, persistant angulation, joint stiffness and sometimes severe limb length discrepancy sequellae. Numerous treatments based on biological and/or mechanical concepts, surgical or not, have been reported with variable success rates. Vascularized fibular grafts and the Ilizarov technique have greatly transformed the prognosis of CPT. Despite these steps forward, repeated surgical procedures are often necessary to obtain bone union and the risk of amputation is never entirely eliminated. The effectiveness of new treatments (bone morphogenetic protein, bone marrow stromal cell grafts, pulsed electromagnetic fields, induced membrane technique…) still requires to be confirmed. Combining these new techniques with existing treatments may improve the final prognosis of CPT, which nevertheless remains poor.