Clinical History
Pseudoarthrosis in a young child with bow leg.
Imaging Findings
This little girl was found to has increasing bowing of her right leg by her parents. She was referred to a paediatrician who organized a plain radiograph. This showed antero-lateral bowing of the
tibia with pseudoarthrosis of the mid-portion of her fibula. She was diagnosed with neurofibromatosis after tests confirmed the diagnosis. There were no family history of the condition of note. She
has been given an ankle foot orthosis to wear until such time when an osteotomy correction of the deformity will be performed.
Discussion
Neurofibromatosis is a hereditary disorder affecting numerous systems of the body, including the central and peripheral nervous systems, skeleton, skin and deeper soft tissues. Two distinct types
exists; neurofibromatosis type-1 (NF-1), is known as von Recklinghausen's disease or peripheral neurofibromatosis, is due to a defect in chromosome 17. Neurofibromatosis type-2 (NF-2) or central
neurofibromatosis results from a defect in chromosome 22. Children with spinal deformities or congenital tibia pseudoarthrosis are usually affected with NF-1. Up to 55% of anterolateral bowing and
pseudoarthrosis of the tibia are associated with NF-1. Associated features of NF-1 are cafe-au-lait spots, axillary freckling and cutaneous neurofibromas. Although NF-1 can be inherited in an
autosomal dominant fashion, about 50% of all cases are thought to result from new mutations. Tibia pseudoarthroses are not clinical apparent at birth and patients usually present to the orthopaedic
surgeon with tibia bowing that, over time usually fracture and result in pseudoarthrosis. Treatment of tibia bowing is primarily the prevention of fracture by prophylactic bracing. Surgery by
intramedullary nailing, vascularized fibular grafting and external fixation have been described.
Differential Diagnosis List
Pseudoarthrosis of the tibia in neurofibromatosis.
Final Diagnosis
Pseudoarthrosis of the tibia in neurofibromatosis.