| Definition
Pseudarthrosis, a false joint associated with abnormal movement
at the site. Congenital pseudoarthrosis refers to a spontaneous
fracture which progresses to non union, this is rarely present at
birth but commonly develops during the first 18 months of life. The
tibia is the most frequently affected site associated with
congenital anterolateral tibial bowing in neurofibromatosis which
progresses to pseudoarthrosis (see tibial pseudarthrosis).
Congenital pseudoarthrosis may also occur in the fibula, radius,
ulna, femur and clavicle, when it is seen on the right.
Pseudoarthrosis may appear when bone fails to bridge the gap
following a traumatic fracture, especially if it becomes infected,
surgical osteotomy, arthrodesis or fusion operation. Chronic joint
dislocation may be complicated by formation of a pseudoarthrois,
this is most commonly seen at the hip where a superolaterally
displaced femoral head may form a false articulation with the ilium.
Pseudarthrosis may also develop at sites of accessory ossification
and cause pain. Typically, this is seen in the navicular bone. It is
also a common complication of incomplete tarsal coalition with a
fibrous bar. The edges of the lesion are irregular in tarsal
coalition but are smooth and rounded in other pseudarthroses.
Tibial pseudarthrosis, congenital anterior tibial bowing (see tibial
bowing anterior), which progresses to spontaneous fracture and
subsequent fibrous nonunion. The fracture is rarely present at birth
but commonly develops during the first 18 months of life.
Radiographs initially show bowing of the tibia convex anteriorly or
anterolaterally with narrowing of the tibial shaft and sclerosis
encroaching on the medullary cavity at the apex. The apex of the
curve is typically at the junction of the middle and distal thirds
of the tibial shaft. Following fracture and nonunion radiographs
often show a pointed distal fragment and cupped proximal fragment
which fit together to form a false joint. There is often associated
tibial shortening. In approximately 50% of cases tibial
pseudarthrosis (Fig.1) is associated with neurofibromatosis and in
such cases there may be a lytic lesion seen within the tibia. This
is often in the distal third of the shaft but can occur at any
level.
Congenital pseudoarthrosis of the radius. Congenital pseudoarthrosis
of the radius (CPR) is rare. Only ten cases seem to have been found
in the literature. Congenital pseudoarthrosis of the radius usually
is associated with neurofibromatosis or fibrous dysplasia. This is a
report of a congenital pseudoarthrosis of the left radius associated
with congenital dislocation of the left hip in a five-month-old
girl. Apart from the pseudoarthrosis, there were no visible
abnormalities. This patient was treated successfully with excision
of the pseudoarthrosis, shortening osteotomy of the ulna, grafting,
and intramedullary fixation of both the radius and the ulna. Review
of the literature disclosed the extreme difficulties in treating
this condition. It was also found that vascularized fibular graft
has been used successfully.
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