External Fixation of the Lower Limb 2

8/8/2019 External Fixation of the Lower Limb 2

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EXTERNAL FIXATION OFEXTERNAL FIXATION OF

THE LOWER LIMBTHE LOWER LIMB


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The term 'external fixation' is normallyThe term 'external fixation' is normallyreserved for systems of fixation, whichreserved for systems of fixation, whichutilize an external frame to connect screwsutilize an external frame to connect screwsor pins transfixing the main boneor pins transfixing the main bone

fragments. The systems currently in usefragments. The systems currently in usevary in both the number and diameter ofvary in both the number and diameter ofthe pins and in the size and shape of thethe pins and in the size and shape of the

external framesexternal frames


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Types of exernal fixatorTypes of exernal fixator

Unilateraland bilateral framesUnilateraland bilateral frames::unilateral frames typically have a frame onunilateral frames typically have a frame on

one side to which pins may be connected.one side to which pins may be connected.The frames differ in the degree ofThe frames differ in the degree ofcomplexity of the connecting unit and alsocomplexity of the connecting unit and alsoin the facility to add extra connectingin the facility to add extra connectingbars, which may lie in different planes, orbars, which may lie in different planes, oron the opposite side of the limbon the opposite side of the limb


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BomechanicsBomechanics

In general, the main bone fragments should be fixed atIn general, the main bone fragments should be fixed ata minimum of two levels. The stability of the externala minimum of two levels. The stability of the externalfixation is increased by having a larger number of pinsfixation is increased by having a larger number of pinsand by spacing them as far apart as possible on eachand by spacing them as far apart as possible on eachfragment. There should also be as small a distance asfragment. There should also be as small a distance aspossible between the bone and the bar of the externalpossible between the bone and the bar of the externalfixator, while still allowing pin track and wound care. Thefixator, while still allowing pin track and wound care. Thebiomechanical requirements of the external fixatorbiomechanical requirements of the external fixatordepend on the condition it is being used for.depend on the condition it is being used for.


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FracturemanagementFracturemanagement

During fracture healing, the externalDuring fracture healing, the externalfixator acts to:fixator acts to: Stabilize the skeletonStabilize the skeleton

Enhance soft tissue healingEnhance soft tissue healing

Hold the limb in the correct alignmentHold the limb in the correct alignment

Provide a suitable mechanical environment forProvide a suitable mechanical environment forfracture healing.fracture healing.


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INDICATION OF EXTERNALINDICATION OF EXTERNALFIXATIONFIXATION

Stabilization

Trauma

o Open fractures

o Pelvic fractures

o Multiple long bone fracture

o Certain unstable fractures in long bones

o Non-union

Arthrodesis


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OsteogenesisOsteogenesis Limb lengtheningLimb lengthening Filling segmental defects resulting from:Filling segmental defects resulting from:

TaumaTauma

OsteomyelitisOsteomyelitis

Tumour surgeryTumour surgery


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Correction of deformityCorrection of deformity Joint contracturesJoint contractures Severe club footSevere club foot Repeat club foot surgeryRepeat club foot surgery


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Advantages of external fixationAdvantages of external fixation

GeneraladvantagesGeneraladvantages Mechanical environment can be controlled duringMechanical environment can be controlled during

fracture healingfracture healing Gradual correction of deformity if possibleGradual correction of deformity if possible

Gradual increase in load can be taken the skeleton asGradual increase in load can be taken the skeleton asthe frame is destabilizedthe frame is destabilized Stiffness of the healthy bone be measured easily to testStiffness of the healthy bone be measured easily to test

for adequate healingfor adequate healing Rapid stabilizing is possible using unilateral framesRapid stabilizing is possible using unilateral frames

Comparatively short learning curve (especially forComparatively short learning curve (especially forunilateral frames)unilateral frames) The limb can be suspended from the frame after skinThe limb can be suspended from the frame after skin

grafting, so that no pressure is put on the skin graftgrafting, so that no pressure is put on the skin graft Allows compression and closure of soft tissue woundsAllows compression and closure of soft tissue wounds


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Advantages over plasterAdvantages over plaster

castscastsAllows early movement of adjacent jointsAllows early movement of adjacent joints

Regular dressings can be carried out easilyRegular dressings can be carried out easily Soft tissues can be observed (eg theSoft tissues can be observed (eg the

perfursion of skin flaps can be monitoredperfursion of skin flaps can be monitoredand the neurovascular status of the limband the neurovascular status of the limbcan be observe for evidence of acan be observe for evidence of acompartment syndrome)compartment syndrome)


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Advantages overinternalAdvantages overinternal

fixationfixation Does not cause stripping or devascularization ofDoes not cause stripping or devascularization of

the fracture fragments.the fracture fragments.

Low blood lossLow blood loss

Less hazardous to carry out if the sterility of theLess hazardous to carry out if the sterility of the

operating area is suboptimal (eg in field hospitaloperating area is suboptimal (eg in field hospitalunits)units)

Does not always require intensification (which isDoes not always require intensification (which isessential for distal locking of intramedullaryessential for distal locking of intramedullary

nails)nails)


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DisadvantagesDisadvantages

TimeTime--consuming to construct (particularly circularconsuming to construct (particularly circularframes)frames) Constant meticulous pin care is essentialConstant meticulous pin care is essential a majora major

drawback with nondrawback with non--compliant patients or those living incompliant patients or those living inan unhygienic environmentan unhygienic environment

Fractures can occur though the pin holesFractures can occur though the pin holes

pin track infectionpin track infection Neurovascular impalementNeurovascular impalement::. Vessel penetration,. Vessel penetration,

thrombosis, aneurysms and intravenous fistulas .thrombosis, aneurysms and intravenous fistulas . Muscle and tendon transfixionMuscle and tendon transfixion:: The subcutaneousThe subcutaneous

surfaces of the tibia is a good site to insert pins becausesurfaces of the tibia is a good site to insert pins becausemuscle or tendon transfixion is unlikely. Other sites ofmuscle or tendon transfixion is unlikely. Other sites ofinsertion for unilateral pins and transfixing wires mayinsertion for unilateral pins and transfixing wires maylead to muscle Bellies being tethered .lead to muscle Bellies being tethered .


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THANK YOUTHANK YOU

External Fixation of the Lower Limb 2

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