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congenital pseudoarthrosis

Wednesday 2 June 2010

A pseudoarthrosis (false joint) usually occurs in adult life as a complication of a fracture. However, it may also manifest at birth or during infancy, commonly in the shaft of the tibia (or rarely the ulna).

The lesion is usually observed at the level of the junction of the middle and lower third of the bone shaft. This type of pseudoarthrosis is considered congenital and constitutes a distinct orthopaedic entity.

Radiographic evaluation of an infant with congenital pseudoarthrosis reveals discontinuity in the diaphysis of the affected bone, associated with a characteristic tapering of the bone ends at the site of the pseudoarthrosis.

Histologic examination reveals dense, fibrous connective tissue filling the defect.

Neurofibromatosis type 1 (NF1) is present in a high percentage of children with this condition, and as many as 10% of patients with neurofibromatosis type 1 have the disorder.

Nevertheless, neurofibromas are not usually recognized on microscopic examination of histologic specimens from the involved site. These lesions usually prove to be very refractory to treatment.

Radiology

- The appearance of the lesion at the junction of the middle and lower third of the bones and the tapering of the bone ends are characteristically found in patients with congenital pseudoarthrosis.

Microscopy

- the gap in the bone is filled with dense, fibrous connective tissue, with no significant new bone formation.

See also

- bone repair
- fibrous tumors of bone
- fibrous lesions of bone