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Limb
legth discrepancy is being a cosmetic problem and further creating functionally
orthopaedic problems. Owing to both gait pattern changes dependent upon the imbalance of
the frontal plane and degenerative changes in the axial skeleton, orthopaedic surgeons are
very closely interested in the treatment of this pathology.
The treatment of the lower limb length
discrepancies is being a disputatious subject for years and because of its possible
complications (adverse effects ) is no longer preferred by some orthopaedic surgeons. In
the history of orthopaedics there have been many periods following each other in which the
current choice of treatment varied. One of these was the limb lengthening procedure and
has been applicated frequently until its complications were seen. Following the
technologic developments the limb lengthening became a current and widespread treatment
modality again. Codivilla published the first lower limb lengthening method in 1905.
Pain, contractures, avascular necrosis,
neurovascular problems and other complications were frequently seen because the whole
lengthening was done at the same time. To avoid of these complications it is suggested to
shorten the uninvolved limb. According to this idea Phemister et al. published the
technique of the epiphyseodesis in the uninvolved limb in 1933. The surgical techniques
based on acute lengthening were describedby Wasserstein after 70’ies. Winquist, Hansen
and Pierson described the shortening osteotomies of the uninvolved limb in 70’ies. Again
in 70’ies the concept of distraction osteogenesis ( 1mm per day bone distraction results
new bone formation in the distraction gap ) has been defined in the leadership of Dr.
Ilizarov in the old Soviet Union. Ilizarov et al. in this country, Monticelli and Spinelli
in Italy used circulary ; DeBastiani in Italy used unilaterally external fixators for
gradually lengthening procedures.
Today it is necessary, as it is in other
treatment modalities, for the modern life style that the postoperative follow up period of
the limb legthening is comfortable and that the hospitalization time is short. Due to
these necessities it has been started to search new modalities in limb lengthening. The
Salter-like osteotomy described by Millis&Hall and the shortening osteotomy of
Winquist are the products of this search. But these ostetomies did not meet the
requirements enough. The studies continued and Kempf&Grosse in 1985, Paley et al. in
1997 published the most comfortable method in which the hospitalization time was the
shortest of all. This method is also applied first in Turkey by Dr Mehmet Kocaoğlu and Dr
Mehmet Çakmak in 1997 at Istanbul Medical Faculty Department of Orthopaedics.The
technique, being applied successful at present time, is shown with its details below.
Lengthening over an intramedullary nail ; (surgical
technique) (Picture 1) :
Step
1
Insertion of the intramedullary nail and osteotomy:
The patient is placed supine on a traction table whit the limbs in scissors
position and the uninvolved limb lies down. Via the standard approach through the
piriformis fossa the medulla is reamed over a guide wire to a diameter 1.5 millimeters
larger than that of the intramedullary nail. The proximal part of the femur is overreamed
because the proximal part of the nail is larger. On the x-ray the level of the osteotomy
is planned.During planning the ostetomy one has to remember that it is necessary for
stabilization to leave at least eight centimeters of the nail distal to the osteotomy
level at the and of the lengthening. The corticotomy is completed percutaneous with a
corticotome. Then the guide wire is advanced into the distal segment so that the length of
the nail can be measured. The nail of appropiate size is inserted and it is locked
proximally. After placing a suction drain the first step of the technique ends.
Picture 1
Step
2
Application of the external fixator:
2-3 Schanz screws proximal and 2-3 Schanz screws distal to the osteotomy level are
inserted without coming in contact with the intramedullary nail. There should be at least
more than 1mm space between the Schanz screws and the intramedullary nail.
Step
3
Postoperative Care:
Distraction ( the method of taking the bony fragments away from each other ) is
started in the tenth day. The rate of the distraction should be 0.25 mm four times a day.
The ROM exercises of the hip and the knee
should begin post-op in the first or second day.
The treatment of lower limb length
discrepancies have been difficult for years even to the patient and the physician. After
Dr. Ilizarov described the concept of distraction osteogenesis there have been advanced
new techniques which initiated a new era with lower incidence of complications.
Today we can arrange special features of
limb lengthening procedures as follows : application time, providing alignment ( the
mechanical and anatomical axes of bone ), total number of operations, protecting the
regenerate against refracture, minimizing the pin track infections and its possible
complications, maintaining range of motion, healing time, comforts in activities of daily
living and the cost of the treatment.
Our current choice is the combination of
unilateral dynamic external fixator and an intramedullary nail to maintain the length and
the alignment after lengthening. The prerequisities of this method are that the smallest
diameter of the medulla must be larger than 7 mm and that there must be leaved at least 8
cm of the nail distal to the osteotomy level at the end of the lengthening.The
intramedullary nail neutralizes the shearing and bending forces to the femur during
lengthening, shortens the external fixation time and protects the regenerate against
refracture. In our series a subtrochanteric femoral ostetomy is performed in one case. We
did not determine any disadvantage as varus angulation in spite of an intramedullary nail.
Radiologic evaluation of our cases did not
show any tendency to form valgus deformity. We did not observe valgus deformities in our
series while some authors suggest these as disadvantages of the lengthening over a nail
technique.
Ilizarov emphasized the importance of the
endosteal circulation for distraction osteogenesis . We reamed the medulla in all of cases
before inserting the intramedullary nail. In spite of that callus formation time was not
longer than expected. That’s why we don’t believe that the deficiency of medullary
circulation results in slowing of new bone regeneration. Revascularization after reaming,
the stability of the fixation with intramedullary nail early functionally loading compose
the basis of this reality .
The potentiel disadvantages of the
combination of the methods of external and internal fixation are increasing blood loss,
intramedullary infection, fat embolism and excessive metal load. The most frightening of
these is propably the widespread of pin track infection to osteomyelitis. In our series we
did not have any case with osteomyelitis. To avoid this complication distal locking should
performed medially should not allowed any contact between the intramedullary nail and the
screws of the external fixator .
Another complication of the lengthening
over a nail in children is to injure the trochanteric apophysis while inserting the nail
resulting in coxa vara deformity secondarily . In our series all cases were skeletally
mature except one who was 12 years old. At follow up we did not observe a coxa valga
deformity until today by this case.
The combination of intramedullary nail and
external dynamic axial fixator is more difficult techniqually then the standard
applications of Ilizarov. But it became attractive because of following advantages: the
shortening of the external fixation time, protecting against refracture, early
rehabilitation, maximal gain of range of motion and the comfort in activities of daily
living. These advantages are more important then the disadvantages such increasing cost,
increasing blood loss and potentially deep infection.
As a result of our observation the
technique of the lengthening over an intramedullary nail is a reliable and durable method
and brings a few advantages over the standard applications of Ilizarov.
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