Ortopedická protetika Praha sro - Společnost pro pojivové tkáně

ss, and trabecular number and thickness
in OI bone. Individual osteoblasts produce
a reduced amount of bone in OI, but
due to their increased number, the bone
formation rate is increased. This does not
lead to a net gain in bone mass however,
because osteoclastic activity is also increased.
Together these findings indicate a high
turnover state with minimal net gain in
bone mass. The increase in bone turnover
is reflected in increased serum and urinary
levels of markers of bone resorption
(deoxypyridinoline and N-telopeptide) and
bone formation (alkaline phosphatase and
osteocalcin). The reduction in core width
seen on trans-iliac bone biopsies translates
into thinner long bones with a reduced
polar moment of inertia, further increasing
the propensity to fracture (7).
IN SUMMARY
a) Bone Quality
The bone matrix is defective. There is
a relative increase in woven bone and a decrease
in lamellar bone.
b) Bone Quantity
The amount of cortical and trabecular
bone is decreased. Bone cortices are thin,
trabeculae are thin and fewer in number.
Histology shows decreased osteoblastic
activity on the periosteal surface and increased
osteoclastic activity on the endosteal
surface.
c) Bone Geometry
Normal diaphyseal bone is tubular or
pipe-like. In OI the pipe walls are thin
with defective lamination and the diameter
is narrow causing weakness. Recurrent
fractures and the abnormal nature of OI
bone results in progressive deformity. Bent
bones are inherently weaker and susceptible
to further deformity and fracture.
TREATMENT OF OI
The aim of treatment in OI is to maximize
mobility and other functional capacities.
The optimal treatment approach involves
an interdisciplinary team consisting of orthopaedic
surgeons, physicians, geneticists,
rehabilitation specialists, physiotherapists
and occupational therapists.
SURGICAL TREATMENT
The risk of recurrent fractures and
progressive deformity can be reduced by
internal metal fixation. The use of intramedullary
nails is the treatment of choice.
Various techniques have been over the last
thirty years. These include:
– stacked Kirschner wires
– solid Sofield rods
– telescopic nails
The standard practice at our institution
for many years has been to use solid Sofield
rods (8). Inserted into the tibia across the
calcaneus and ankle joint; and inserted into
the femur through the knee joint. The placement
of a straight rod in a bent bone
requires correction of malalignment at the
time of fixation. Correction of the bony
deformity in very young children can often
be achieved by closed osteoclasis. In older
children osteoclasis can still be achieved
facilitated by drill holes at the apex of the
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