Congenital tibial pseudoarthrosis of the tibia describes abnormal bowing that can progress to a segment of bone loss simulating the appearance of a joint. The condition is usually apparent shortly after birth and is rarely diagnosed after the age of two.
The aetiology is unclear, however, around 50% of cases are associated with neurofibromatosis type 1 (NF1). Overall, 10% of patients with NF1 are diagnosed with tibial pseudoarthrosis.
Congenital ulnar psuedoarthrosis and radial pseudoarthrosis can also occur, but much less frequently, and usually only in patients with NF1.
- progressive bowing (usually anterolateral in the tibia)
- resorption of short segment of bone
- usually at site of maximal bowing
- usually between mid and distal one third of shaft
- angulation at site of absent bone segment
- often mimics appearance of a joint
- cupping of the bone proximal to the absent section
- sharpened narrow appearance of the distal bone
- often fracture or bowing of accompanying bone (fibula with tibia, radius with ulnar)
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