External fixator

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External Fixator External Fixator

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“External Fixator is a device uses for stabilization and immobilization of long bone open fractures.”

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History

Earliest recognizable External fixations by Malgaigne 1840 pin for tibial fractures, griffe for patella

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Keetley 1893, Ollier,

Roux

History

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Parkhill 1894 Threaded pins and clamp

History

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Lambotte 1902, self tapping threaded pins, rod, adjustable clamps

History

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In 1917. Humphry is the 1st man who uses threaded pins, but he uses only one pin above fracture and one below the fracture site.

In 1948, Charnley popularized his compression device to facilitate arthrodesis of joints.

History

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In 1966 and 1974,Anderson et al. uses transfixing pins incorporated into a plaster cast for management of large series of tibial shaft fractures .

From 1968 to 1970 Vidal and Vidal et al. modified original Hoffmann device from a single half –pin unit to a quadrilateral bicortical frame , greatly increasing rigidity.

History

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Today's Fixators

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Type -1 Unilateral Uniplanar Type -2 Uniplanar Bilateral. Type -3

Classical Bilateral Biplanar. Delta Unilateral Biplanar

According to Planes: Planner: Hoffman’s, orthofix etc. Circular: Ilizarov

Types

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Biomechanics of External Fixator

Intrinsic stability of frame (S)

EX I

S = ----------- L

E=modulus of elasticity =constantI= moment of intertia= constantL= distance of frame from axis.

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Thus Stiffness is inversely proportional to the distance of the assembly from the bone

(closer the frame to bone -more stable

assembly)

Biomechanics

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Mechanics of Bone Pin

Interface

To increase stability of bone –pin interface

1. Adequate no. of pins in each fragments

( 2 for most bone & 3 for femur)

2. Increase pin pitch (3.5mm)

3. Increase size of pin

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A. Schanz screw 4. 5 short threaded for diaphysis 5 mm long threaded for metaphysisB. Clamps 1) Universal Clamps 11) Open ended clamps 111) Transverse pin adjusting clamps 1v) Tube to tube clamps.

C. Tubes 11mm

Basic Components

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Basic Components

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Drill : Hand Drill

Drill bits – Long drill bits( 200mm) 3.5 and 4.5 mm diameter.

Triple guide assembly , consist of trocar(3.5mm), inner Sleeve and outer sleeve

T Handle for insertion of the Schanz screw.

Required instruments

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Required instruments

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External fixation of the tibia is advocated in severe open fractures (Gustilo 3b,3c) closed fractures with severe soft-tissue injury open fractures involving bone loss compartment syndrome after fasciotomy adjunct to internal fixation limb lengthening or bone transport

Indications

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Soft tissue healed If the soft-tissue injuries

have healed satisfactorily within 2 weeks without pin track infection, the external fixation can be removed.

It is then replaced by internal fixation with either a plate or a nail.

External fixator as temporary device

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Soft-tissue problems persist Remove the external fixator Temporarily stabilize in cast Let pin track infection heal

If there is pin track infection, using a nail (especially with reaming technique) can lead to intramedullary infection.

In this case plate osteosynthesis is clearly preferable.

External fixator as temporary device

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In the event that soft-tissue healing is not satisfactory after 4-6 weeks, and there is no pin track infection, the external fixator can be left on until the fracture has healed.

In children fracture healing is often completed within a period of approximately 6-8 weeks.

External fixation as final fixation

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External fixation as final fixation

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Less damage to blood supply of bone

Minimal interference with soft-tissue cover

Useful for stabilizing open fractures

Rigidity of fixation adjustable without surgery

Good option in situations with risk of infection Requires less experience and surgical skill than

standard ORIF Quite safe to use in cases of bone infection

Advantages

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Pin Track Infection. Neurovascular Impalement. Muscle or Tendon Impalement Delayed Union. Compartment Syndrome Re-fracture Limitation of further Alternatives. Cosmetic Problem

Complications

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IM nails vs External fixator

Henley (Clin. Orth., 1989) randomised study of

104 case II-IIIB tibial fractures by unreamed IM nail;

70 treated by external fixation.

Infection rates 7% IM nail, 11% external fixation.

There was no difference in time to union.

Follow up in 1998 (Journal Orth. Trauma.): “The severity

of soft tissue injury rather than the choice of implant

appears to be the predominant factor influencing

rapidity of bone healing and rate of infection”.

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Open fracture Tibia and Fibula Open fracture Femur Floating Knee Open Fracture Humerus Communited fracture distal Radius Pelvic fracture.

Site of insertion

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Tibial Safe Zone

Proximal part of the proximal tibia

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Tibial Safe Zone

Proximal 3rd distal to tibial tuberosity

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Tibial Safe Zone

Mid Shaft

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Tibial Safe Zone

Distal 3rd distal of tibial Shaft

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Schanz screw insertion

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Schanz screw insertion for Metaphysis

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Technique of Applications After adequate skin incision Insert assembled

triple sleeve and push onto bone.

Hold the sleeve steady and lightly tap the trocer on to the bone surface in order to create the initial impression. This prevents slipping of the drill bit during drilling.

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Remove the trocar, insert the long 3.5 drill bit through inner sleeve and drill through both cortices.

Withdraw the drill bit along with inner sleeve. Insert 4.5 mm drill bit through the outer sleeve and over drill the near cortex.

Technique of Applications

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Place a 4.5 mm Schanz screw onto the T-handle. Introduce through the outer sleeve and insert into the bone till the thread are securely engaged into the far cortex.

Technique of Applications

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Insert the triple sleeve through an adequate skin incision and push onto bone.

Drill the both cortex bone with 3.5 mm drill bit.

Insert 5mm long threaded Schanz Screw with T-handle.

Technique of Applications for metaphysis

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Place the most distal Schanz screw using the standard technique.

Place a universal clamp onto the schanz

Fix a 11mm tube in this clamp, so that it is posterior to the schanz screw.

Application of external fixatorApplication of external fixator

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Slide 3 Universal

clamps onto this tube.

Insert most proximal schanz screw.

Reduction of bone.

Fix the proximal schanz screw.

Application of external fixator…Application of external fixator…

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Insert the 3rd 4th

schanz screw accordingly.

Connect frame with another Tube.

Second tube is clamped in “mirror image” fashion after prestressing.

Application of external fixator…Application of external fixator…

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In the OT

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In the OT

Open fracture Gustilo IIIB with Fixator

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In the OT

Flap Coverage

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Ilizarov External Fixator.

Universal Mini Fxternal Fixator.

Modular external Fixator

Other External Fixators

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Universal Mini External Fixator Micro-motion at fracture Site. It is bi-lateral More lighter than traditional External Fixator. More ligamentotasis Less chance of pin tract infections.

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UMEX

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Modular variety of External Fixator The modular external fixator allows

the surgeon to reduce the fracture by manipulation and to hold the reduction.

Free pin placement allows the surgeon:

to spread both pins, thereby increasing frame stiffness,

to position pins according to the fracture pattern or soft-tissue injury,

to avoid injury to nerves or vessels.

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Modular variety of External Fixator

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Other variety of External Fixator

Synthes Adjustable Tibial exfix

Hoffman II external fixation system

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Conclusion External Fixator is a good device for the

management of open and complicated fractures.

Surgeon must have knowledge about neurovascular plane of the involved Organ.

Skill for applying the fixator.

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References Course manual: The 3rd Annual Fracture fixation Course;

Eastern India Initiative for Orthopaedic Training

Uses of External Fixator in orthopaedic surgery; Dr. ABM Golam Farque; a Power Point Presentation.

Wheeless' Textbook of Orthopaedics http://www.wheelessonline.com/ortho

Synthes: leading global medical device company. http://us.synthes.com/

AO Foundation. <www.aofoundation.com>

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Thank YouThank You

External fixator

Health & Medicine

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