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Elastic osteosynthesis is
suitable for humerus mainly because it is a
non-weight-bearing bone. It is subject to muscular
compression which shortens the bone's length. This
can result in perforation of the proximal extremity
by the K wires with subsequent loss of the
reduction. To prevent this major drawback the
authors report their experience with an original
implant. It seems to preserve efficiently the
trophic value of a non invasive treatment but also
to provide secure bone length restoration. These
original wires are simple to use and check because
no stock of different sizes of implant is
necessary.
The surgical treatment of
humeral fractures is increasingly frequent, mainly
in patients with multiples fractures or severe
initial displacement or in the elderly who need a
rapid and definitive procedure. Light elastic
osteosynthesis seems to be suited to humerus, but
the frequent migration of the K wires through the
proximal epiphysis has led to neglect of this
method. New methods use intramedullary nailing,
whose aim is initially an immediate and secure bone
stability. Nevertheless this rigid nail does not
respect the physiologic muscular activity, which is
probably the sole compression-inducing factor in a
non-weight-bearing bone.
Material and
methods
Elastic osteosynthesis uses
Kirschner's wires which are introduced distally,
according to Hackethal an April. The patient is
placed dorsally in case of a lateral supra-condylar
approach or ventrally in case of supra-olecranion
way. A thin 0.5 cm/3 windows is opened in the
cortex and the wires are introduced in the
medullary canal, and pushed proximally to the
subcondral head cortex, under image intensifier
control. The wires have their proximal extremity
curved in a loop as narrow as necessary to allow a
simple an easy movement inside the medullary
cavity. The distal extremity is twisted, cut and
blocked in the distal window. Two of five wires are
used, only reaching a proximal cortical contact and
a simple distal locking, but never aiming to fill
of the medullary cavity. The distal extremity is
twisted, cut and blocked in the distal window.Two
to five wires are used, only reaching a proximal
cortical contact and a simple distal locking, but
never aiming to fill of the medullary cavity. Two
kinds of "loop" wired were used. The type I was
fist used from December 1992. Type II has been used
since December 1995. This comprises a long part and
a short one figure of "hook". the length of the
short part is around 10 cm. This wire has the same
elasticity as a single K wire.
From December 1992 to
December 1996, 56 fractures of the humerus were
treated using "loop" wires.in 46 cases the lateral
approach was used, in 10 cases the dorsal approach
was elected. All the patients were followed as long
as necessary, only one case was lost to view after
two months. The results were studied clinically and
radiologically.Clinical result concern the bone
healing and the function of the shoulder which is
considerated as excellent when abduction and
flexion reach 150 to 180°, good with a range
of motion between 120 to 150°, poor with a ROM
between 90 to 120° and bad when the Rom is
less than 90°. No evaluation of elbow mobility
was necessary because it was always normal.
Radiologic studies concern the period form firm
callus formation and the shaft alignment. No
torsional deformity was discovered. Axial deformity
was classified as a mal-union when more than
15°+. Non-union means no firm radiologic
callus after a 6 months period.
Results
56 fractures of the humerus
were operated, from December 1992 to December 1996
in 42 womens and 14 males, aged from 15 to 92 years
(m.age=65,4 years). 28 left sides and 28 right
sides were treated. They comprised :
- 27
proximal metaphiseal fractures including 13
neck fractures, 7 three-part and 7 comminuted
fractures.
- 27 shaft fractures
including 13 proximal 1/3, 13 middle 1/3 and
1 distal 1/3 fractures.
- 2 remaining compound
fractures were analysed. In the shaft
fractures the ethiologic mechanism was 17
flexions ) and 10 spiral torsions. The mean
follow-up was 7,5 months (range 2 to 24
months).
The functional result concern
the shoulder range of motion which was :
-
excellent in 13 cases
- good in 10
cases,
- poor in 11
cases
- bad in 1
case.
This means 78 % of excellent
or good functional result.One case was lost to view
after two months.
The radiologic results
concern callus formation period :
- 37
cases healed in less than 3 months
- 10 cases in from 3 to
4 months
- 6 cases in from 5 to
6 months
- 2 fractures were
unhealed after 6 months: one neck fracture in
an old woman (92 years) and one cephalic
fracture (4 part fractures) in which
conservative treatment was a mistake. no case
of non-union were seen apart from the two
mention above.
Three secondary
head and and three extra-articular cortical
perforations are stressed out of the 43 patients
treated with type I wires. Three secondary removals
were necessary after a period of two months with no
complications. No perforation was seen in the type
II wires series. five cases of malunion, all in
proximal fractures, were seen but with only two
poor and three good functional results. No bone
infection and no refractures were founds, nor any
necrosis of head.
Discussion
The functional
or non operative treatment is still currently used
1
23.
First codified by Bohler in 1966 27
20,
it was improved by Sarmiento in 1977
7
27
29.
It can result in non-unions 21,
5 % to 6,3 % according to Jeffrey 14
or André 1,
but also in a long and tedious follow-up, mainly in
the elderly, with 15 % of delayed union
3
14
and 2 to 6 months before good functional
restoration 7
21.
Plate fixation
makes it necessary to open and expose the fracture
21
24
which can induce delayed union of up to 39 %
according to Stern 31,bone
infections 9
11
31
radial nerve palsy 4
30
and non-unions 3
9
of up to 10,2 %according to Hall an Pankovich
12.
The union delay is generally long, sometimes up to
one year according to Bell or Vandergriend
4
32.
Futhermore the callus is often of poor quality
15.
The supple
osteosynthesis aligns the fragments with no rigid
material.It was described by Rush 21
and Ender 6
12
or more recently Hackethal 8
26.
It is easy and cheap but is so far limited by a
lack of stability, especially in proximal fractures
3
8
12
18
and osteoporotic bone 2
10
18
even if measures are taken to improve the proximal
wire fixation 2.
The semi-rigid
osteo-synthesis was described by Kuntcher
8
17,
which concept is due to the success of the nailing
in the lower limbs 15.Closed
nailing provides an accurate bone alignment, and
length restoration 10
13
22
27
mainly the recent Seidel's nail which consist of a
distal locking device 13
16
25
30.
In this procedure a static interlocking prevents
any secondary collapse or torsional displacement.
But the humerus is a non weight-bearing bone
8
14.
This mechanical and physiologic constraints are
differents than the femur or the tibia
13.
For example, accurate axial alignment is not
necessary for an excellent functional
result 3
7
26
and the lack of torsional constraint in the
shoulder joint 14
results in no torsional stress in the shaft of the
bone. The proximal approach necessitates incision
of the deltoid muscle 10
which can induce pain 9
12
27
and Sudeck's atrophy 31.
Reaming may increase the comminution
13
and aggravate the damage to the endomedullary
arterial network 33,
which provides 60 % of the bone's blood-supply. The
distal locking device of Seidel's nail is not
always secure 25
27
sometimes resulting in non-unions mainly in
the distal fractures 13.Around
40 % of all humeral shaft fractures can be treated
by locked-nailing 10
13.
The Nail neutralises the physiologic compression
due to the muscles 28.
Ever since, elastic supple
osteosynthesis remains of great value.It preserves
the trophic muscular action thanks to
an accurate elasticity 7
19
20
. The wires can lightly damage the endomedullary
vascular network 20.The
compressive force is denied by Bonnevialle and
Mansat 5
who wrote in 1989 :" The absence of compression at
the fracture site, since the humerus is a
non-weight-bearing bone, makes useless the major
advantage of endomedullary osteosynthesis". However
Rush wrote in 1950 21
: A continuous traction of the longitudinal muscles
of the arm favourably influences the union by
compressing the bone extremities".This compression
is probably as important for callus formation as
gravitational compression in lower limbs.Only the
orthopaedic treatment or the elastic synthesis
preserve those natural conditions.
The "loop" wires, as far as
allowed by this preliminary study, seem to decrease
the risk of proximal perforation and create the
physical conditions of a true elasticity
20.
No secondary displacement of the proximal and
distal extremities of the wires maintains the
proper humeral length like the intramedullary nail.
But this very simple mechanism allows a primary
stability only thanks to the physiologic
compressive action of the longitudinal muscles.
This also permits us to extend its use to very
proximal or distal fractures. Open osteosynthesis
no longer seems necessary for neck fractures.Open
osteosynthesis no longer seems necessary for neck
fractures; their risk to the blood supply or
mobility is known 8
27.
Conclusion
A preliminary series of 56
fractures of the humerus utilising a new loop wire
is reported. Type I was used in 43 cases with 6
cases of proximal perforation in old patients. Type
II was used in 13 cases with no case of
perforation. Two failures are pointed out
(non-unions) in very proximal fractures.Apart from
these, non-union, no osteomyelitis, no delayed
union, no radial nerve palsy and no osteonecrosis
were discovered. This seems to result from respect
of the natural conditions of healing of the upper
limbs, by preserving the muscular compressive
action according to Rush 28.
The principle of action of these loop wires is to
create a real elasticity, both proximal and distal
extremities being blocked by close cortical
contact. No stock of different sizes of implants is
necessary.
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