Ortopedická protetika Praha sro - Společnost pro pojivové tkáně

deformity. In children who have been treated
with bisphosphonate therapy, the resulting
increased bone density may necessitate
an osteotomy to achieve deformity correction.
Sofield rods are an effective intra-medullary
splint. The fixation technique has a relatively
low complication rate. Disadvantages
are the potential damage to the ankle and/or
knee joint at the time of surgery and the fact
that in time the bone will tend to grow off
the rod with distal bone deformity which
may necessitate rod revision.
Telescopic intramedullary rods have
been available to treat OI for many years
(9, 10). The concept being that the rods
will gradually increase in length with bone
growth, thus avoiding rod revision. However
weaknesses in the instrumentation available
resulted in a relatively high complication
rate (11, 12). The Fassier-Duval telescopic
intramedullary system was developed in
2000 in collaboration with Francois Fassier
at the Shriners Hospital for Children,
Montreal, Canada and Pierre Duval at
Hopital Brome-Missisquoi-Perkins, Quebec,
Canada to overcome these technical difficulties
(13). The intramedullary device has
only 2 components- male and female nails-
each with a thread at one end for fixation in
the proximal and distal epiphysis of a long
bone. The Fassier–Duval IM nails come in
a range of sizes suited to the femur, tibia and
humerus of short stature paediatric patients
over the age of 18 months.
TREATMENT WITH
BISPHOSPHONATES
A major advance in recent years has
come from the introduction of bisphosphonate
therapy, and cyclic intravenous
pamidronate is now viewed as the “gold
236
standard” for the treatment of children and
adults with moderate to severe OI. To date,
little data is available on the treatment of
mild OI or the use of oral bisphosphonates,
although large multinational placebo-controlled
trials are currently underway to
address both these issues.
Bisphophonates are synthetic analogs
of pyrophosphate that bind to the hydroxyapatite
crystal found in bone. They
act as specific inhibitors of osteoclastic
mediated bone resorption. The use of bisphosphonates
in the treatment of children
with OI was pioneered by Francis Glorieux
and colleagues at the Shriners Hospital for
Children in Montreal, Canada. The first
patient was treated in 1992. The most
extensively studied bisphosphonate in OI
is Pamidronate®, a moderately potent amino-bisphosphonate.
Pamidronate has been
reported to decrease bone pain, enhance
well-being, improve mobility and muscle
strength, reduce fracture incidence, increase
long bone cortical thickness, increase
vertebral size with vertebral reshaping,
and increase bone mass and bone mineral
density (15, 16, 17). In an attempt to prevent
growth disturbance and spine and
limb deformity, cyclical intravenous pamidronate
has also been used in babies and
infants with OI. The treatment response
in the younger children was more pronounced
than in the older cohort, but
further follow-up is needed to evaluate if
function, growth, scoliosis and limb deformities
are improved. A multicenter international
trial of the potent bisphosphonate,
Zoledronate®, is currently underway to
assess its dosage, efficacy and safety in OI
compared to pamidronate. Zoledronate has
the benefits of being able to be administered
more rapidly and of having a longer
dosing interval than pamidronate, both of
LOCOMOTOR SYSTEM vol. 14, 2007, No. 3+4