Percutaneous Osteosynthesis of the Distal Fractures of the Femur. Eladio Saura Mendoza e Eladio...

8/6/2019 Percutaneous Osteosynthesis of the Distal Fractures of the Femur. Eladio Saura Mendoza e Eladio Saura Sanchez

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Percutaneous Osteosynthesis of the Distal Fractures of the FemurEladio Saura Mendoza e Eladio Saura SanchezServicio de Ortopedia y Traumatologa, Hospital General Universitario de Elche. Espaa.

Abstract:

The LISS technique in the distal fractures of the femur, is an excellent method to cope

with the drawbacks of the osteosynthesis, especially in a short osteoporotic distal

segment and in the peri-prosthetic fractures.

This percutaneous technique minimizes the injuries to the soft tissues and to vascularnetwork of the bone.

The LISS plate has provides an excellent and lasting stability, due to the design of theimplant, to the anatomic and divergent insertion of the screws, and the locking of the

screws to the plate.

When used as a bridge osteosynthesis it provides biological and mechanical advantages,

not only promoting the formation of callus, but also by better counteracting the loadingforces thus decreasing hardware failure.

But, the final outcome, will always depend on the anatomical reduction of the intra-

articular fractures, and the proper restitution of the axial and rotational alignment of thelimb.

Etiology:

A distal femur fracture, is an articular and/or extra-articular fracture of the distal

epiphysis or metaphysis, and frequently associated to a diaphysial fracture. Theyrepresent 6-7% of all femur fractures.

There are 2 groups of patients: the young patients on the second decade of life, with a

high energy trauma; and the elderly group with a low energy trauma (fall from own

height) in osteoporotic bone.

One third of the cases result form high energy trauma, its a male trauma patient, mostlyinvolved in a MVA.

There is often an articular and patellar fracture associated with this type of injury, when

the knee is bent at the time of impact.

If the injuring force is longitudinal, with the knee in extension, there will be impactation

of the femoral condyles against the tibial plates, causing tibial and femoral fractures with

important displacement of the fragments.


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According to current publications, the most common associated injuries are patellarfractures in 15% of cases and ipsilateral fractures in 20% of cases.

The floating knee may be present in up to 5% of all distal femur fractures. There mightalso coexist soft tissue and ligament injuries of the knee in a 20-30% of cases, meniscaltears and osteochondral defects in a 10% of cases and vascular or neurological injuries in

up to 3% of cases.

Low energy fractures have an increased incidence in the 6th

and 7th

decade of life, moreoften in females. A common cause is a casual fall with rotation of the limb, with a

valgus-varus stress deviation, in an osteoporotic bone.

There has been an increased number of peri-prosthetic fractures of the knee, being more

common in the metaphyseal-diaphyseal region.

The incidence of open fractures ranges from 20 to 40% of all cases.

Classification:

According to the AO Muller classification system, the distal femur is considered to be an

square, in which the height equals the wider section of the epiphysis: The Square of

Heim. In complex fractures, the center of the fracture determines the type of fracture;

but when there is a displace intra-articular fragment, it is always considered and articularfracture.

The femur is coded as number 3, the distal segment as 3, so the anatomical descriptionwill be 33.

In this segment, there are 3 sub-types: A, B and C. Type A is an extra-articular fracture,Type B is a partial articular, in which only one part of the articular surface is displaced

from the diaphysis, and Type C is a complete articular fracture, in which the condilararticular surface is split in at least 2 fragments and are displaced from the diaphysis.

Each type is subdivided in 3 groups: 1, 2 and 3, related to the morphology of the fracture.

Last, each group can be subdivided in sub-group .1/ .2/ and .3.

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Soft tissue classification:

Soft tissue injuries classification is very important. Open fractures are often classified

using the Gustilo classification system, whereas closed severe injuries with skin,muscular or neuro-vascular involvement are best described with the Tscherneclassification system. These are very useful for documentation proposes and decision

making.

Radiological diagnosis:

One should obtain a true antero-posterior and lateral view of the distal femur, when there

is an articular fracture, oblique views are mandatory. When there is articular or

metaphyseal conminution, post reduction x-rays better the understanding of the fractures.

MRI is not standardized for radiological diagnosis, but helps to understand associatedsoft tissue injuries as capsular, ligament, and neurovascular structures.

Soft tissues:

Skin contusion is common in a closed injury, and very frequent in this type of fractures,

either by direct or indirect mechanisms such as displacement of fracture fragments. Skin

boils are a sign of cutaneous suffering.

When this happens, surgical exposure with tissue handling may result in necrosis and

superficial infection. It is always wise to wait for a reasonable period of time to achieve

good soft tissue condition and reduced skin tension.

General pre-operative planning:

Problems treating fractures are diverse and difficult to solve. Conservative treatment is

reserved for cases with minimum displacement, or patients with operativecontraindication due to poor health status.

Patient personality is taken in consideration: age, associated conditions, poor immune

status, severe diabetes, smoking. The fracture personality is also considered, so is thevascularity of the limb, neurological involvement, soft tissue condition, bone stock, joint

function, osteoporosis, etc. These will give the guidelines for fracture treatment.

Treatment Principles:

The treatment principles are the same as for any other fracture, and are well described in

the AO Principles of Treatment textbooks.

-Anatomic reduction of articular fractures.-Restoration of axial and length deformities in metaphyseal-diaphyseal

fractures.


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-Stable osteosynthesis to allow-Early limb mobilization.

And always with the less traumatic surgical approach as possible.

In the decade of the 70s, the AO philosophy, defended the treatment of the inter-supracondylar fracture of the femur, with an extensive lateral approach exposing the

fragments, anatomical articular and metaphyseal reduction, and cortical osteosynthesisusing 2 cancellous screws and a 95 agulated condylar plate, which is still use in some

cases. Often, cancellous bone graft from the iliac bone was used to fill defects, speciallyof the distal cortex 8opposite to the plate).

Todays concepts of biological osteosynthesis, consisting in indirect reduction of the

fractures (without opening the fracture site) and the use of bridge plating in the

metaphyseal fractures, allows preservation of fragment vascularization, thus better and

faster callus formation.

Nevertheless, articular fractures must be anatomically reduced, which may imply direct

exposition of the condyles, through an appropriate surgical approach.

Surgical timing:

Normally, this type of fracture should be treated in a delayed fashion.

In low energy fractures, the definitive treatment should be done early.

In high energy fractures, the risk for skin complications and the complexity of thetreatment, calls for the delayed definitive treatment, once the conditions are stable and thehuman and material resources are available. In trauma patients, after initial urgent

stabilization of all injuries is accomplished, the definitive treatment should be performdepending on the priorities and pre-operative planning of that particular case.

Initial treatment in emergency department should consist in posterior splinting the limb,

with soft padding and light compression bandaging, elevation and rest for a 5 to 7 daysperiod. Skin status is checked without taking the splint out, allowing assessment of soft

tissues.

In case of severe injury with subluxation or important comminution, it is adviced toapply skeletal traction to the tibia (we use a bridge external fixation).

Open fractures demand urgent stabilization and debridement as described in theliterature.


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Surgical treatment options:

We should consider the following factors:

*Fracture Type, assessing the importance of achieving an anatomical articularreduction.

*Associated injuries, specially patellar fractures, proximal tibial fractures, soft tissue

status, and associated ligament injuries of the knee.

*Patients general health status.

*Human and technical resources.

There are 3 options:

A.- Endomedullary nailing, anterograde or retrograde, with proximal and distal

interlocking (in articular fractures associated with cortical osteosynthesis of the

epiphysis).

B.- Cortical osteosynthesis, our technique of choice. Conventional use of plate and

screws.

C.- External fixation, as definitive treatment, or as a first step for as osteosynthesis ornailing.

The Endomedullary nailing has its best indication in fractures with integrity of theepiphyses and metaphysis, and even more in proximal complex diaphyseal fractures.

Non-displaced articular fractures are not a contraindication for endomedullary nailing.Nevertheless, axial deviation in varus and valgus are frequent complications rendering

this localization problematic for nailing.When nailing is used it should be interlocked, to avoid shortening and rotational

deformities, as seen the Kntscher nail.

We started using the interlocking nails in the 70s, with the use of the Grosse nail, andthen with the Universal Reamed AO interlocking nail, static and dynamic, with excellent

outcomes.

With the introduction of the solid interlocked nail, we consider this technique as thetreatment of choice for comminutive, multi-fragmented fractures of the diaphyses of thefemur.

The retrograde nailing is also a valid option for these fractures.


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A Extra-articular fracture

BParcial articular fractureMost of the joint is in contact with the

diaphysis

C

Complete articular fracture

None of the fragments are

In contact with the diaphysis

Fractures of the distal femur, in the metaphyseal zone, with an articular component, canstill be treated with a nail, but with its particular complications and difficulties, despite

being possible to overcome, we recommend the use of cortical osteosynthesis.

Therefore, if the more complexity of the fractures resides in the diaphysis, nailing is stilla good indication; but if the more complexity resides in the metaphysis or is intra-

articular, the best indications will be a cortical osteosynthesis.

Cortical Osteosynthesis:

The classic osteosynthesis begins with an open reduction and interfragmentary fixation

with 2 screws and a 95 monoblock plate, that gives absolute stability to the fracture.

The percutaneous technique, with a conventional plate, DCS plate or with an angular

stability plate, provides the option of a less aggressive treatment.

In more complicated, unstable and comminuted fractures, in which it is not possible to

obtain absolute stability, the use of a bridged plate fixation has been proposed for many

decades.

In our department, the treatment of choice for such fractures in the distal metaphyseal-

diaphyseal portion of the femur is the use of osteosynthesis with percutaneous plates.

External fixation:

External fixation is indicated for open fractures or special cases. In very distal fractures

the AO Hybrid Fixator can be used, it combines the Ilizarov wires in the peri-articularregion with pins in the diaphysial region.

Indications depending on the fracture type:


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Surgical technique:

General anesthesia.

Torniquet use without the use of Esmarch band at this time.

Prepping of the extremity with trichotomy.

Radio-transparent operating table. Lower the opposite leg to allow lateral X-ray vision.

Flex the knee to 30-50 degrees.

C-arm positioned from the opposite side so it doesnt interfere with thetechnique

Sterile drapes and Esmarch at this time. Articular approach for anatomical reduction of the condyles.

Bridging plate according to the percutaneous technique.

Introduction of the LISS plate. Mounting the plate on the back table.

Sub-muscular introduction of the plate, sliding it on the bone with llimitedx-ray control.

Reduction is verified and the axial deviation is corrected at this point.

A 3 cm. incision is made to verify the proper setting of the plate in thebone.

Introduction of a K wire for provisional distal fixation of the plate.

After provisional fixation, reduction is verified with the C-arm.

A 2.8 mm K-wire is placed distally to align the plate to the metaphysis, andan oblique wire is introduced as future guide for the screws so they dont

interfere with the interfragmentary screws. The diaphysial part of the plate is fixed per usual technique; the guide tip

is advance through the anatomical layers, taking care of aiming properlyby means of manipulating the guide to make sure the threads of thescrews correspond to the threads of the plate.

Once the plate is centered and positioned, the screws are introduced in anautomated way.

Still, the ad-latum position can be made better by longitudinal tractionusing the traction device per standard technique.

The diaphysis is then fixed with standard length mono-cortical screws. Itis important to remember to switch from standard hand drill todynamometer before the final tightening of the screw.

The metaphysis is fixed using a depth gauge, by first introducing K wiresto make sure there is no conflict with the interfragmentary screws.

The guide/handle is then extracted, introducing the last screw with a handfree technique.

Then, wound closure with staples, at the skin level.

There should be left 2 aspirative drains, one proximal and one distal. The knee is then mobilized (95-100), checking stability with fluoroscopy.

Compressive bandages are applied.

The leg is positioned in a Braun splint.


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Active motion is allowed without weigh bearing.

CASE PRESENTATION

Female, 75 y.o. patient, after a casual fall, suffers a low energy fracture. Singleinjury. Without relevant medical history.There is not vascular or neurological involvement.Treatment at 24 hours.Fracture type 33.C3.2- Complete multifragmented articular fracture withmetaphyseal comminution.

Surgical technique:

1.- Open reduction of articular fracture.


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2.- LISS plate introduction in the sub-muscular plane.

3.- Radiographic control:


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Complications:

There are 2 types of complications: failure to properly reduce the fracture andfailure of the hardware.

Failures of reduction: Being most important varus and valgus deviation.Procurvatum and recurvatum are well tolerated. Big fragments not reduced in themetaphysis may produce a hipertrophic callus that might interfere with kneemovement.

Bad positioning of the plate: The LISS plate has a high profile and comes pre-

shaped for the type of screws that it uses (LCP screws), it doesnt set against thebone, so it might become elevated from the condyles. This can lead to aninterference with the sliding of the soft tissues around it.Diaphyseal centering: If the plate is not well centered against the diaphysis,some or the screws may end up intracortical.

Errors in the technique: Usually by poor instrumentation and surgeons errors.Improvisation is synonymous of error.

Plate breakage: This can happen when delayed union occurs, and in zones oftension concentration, the latter more common in mid third fractures.

Screws loosening: This can happen in osteoporotic bone or when a poortechnique is applied. If there is that possibility, bicortical screws or regular screwsshould be used.

Hardware removal: The LISS plate requires percutaneous techniques to apply itbut it might require open techniques to remove it, which brings the necessity ofvery strict criteria for the indication for removal. In such cases, one must have allthe instruments necessary for extraction of locked screws.


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RESULTS:

The functional outcomes depend on the fracture type and the injury to the soft

tissues.The percutaneous technique lessens the surgical trauma and promotes healing,it has a lower infection rate and problems with union as compared with the opentechnique.Our experience is similar to the reported in the literature, with a consolidationrates of 90% and infection rates less than 5% in closed fractures.

The LISS plates is stable enough to permit early rehabilitation, in some caseswith increasing weight bearing, without pain and a very rapid recuperation.

Axial deviations superior to 10 are infrequent, but deviation of less than 10 are

frequent.Like any other cortical osteosynthesis, axial shortening is not permitted, and thedegree of stabilization depends on the type of fracture and where the screws arelocated (rigid plating, neutralizing plating, bridge plating).

Percutaneous Osteosynthesis of the Distal Fractures of the Femur. Eladio Saura Mendoza e Eladio...

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