Presentation on theme: "Basic Principles and Techniques of Internal Fixation of Fractures"— Presentation transcript:
1 Basic Principles and Techniques of Internal Fixation of Fractures Brett D. Crist, MDOriginal Author: Dan Horwitz, MD; March 2004Revision Author: Michael Archdeacon, MD, MSE; January 2006New Author: Brett D. Crist, MD; October 2009General ReferencesSchatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, 1987.Hein U, Pfeiffer KM: Internal Fixation of Small Fractures. Springer-Verlag, New York, 1988.
2 “Common” Definitions of Fracture Healing UnionBone’s mechanical stability restored to withstand normal loadsClinically: no pain at fracture siteRadiographically: 3 out of 4 cortices with bridging callusDelayed UnionFx not consolidated at 3 months, but progressive callusNon UnionNo improvement clinically or radiographically over 3 consecutive monthsA fibrocartilaginous interfaceFrom: OTA Resident Course – Russel, T
3 High Energy vs. Low Energy Direct axial load or bending forceFall from height/Motor vehicle crashSoft tissue envelope significantly damagedComminuted fracture patternsOpen fractures“Low Energy“Twisting mechanism or direct load on weak boneFall from standingLess soft tissue injurySimple fracture pattern“High Energy"“Low Energy"
4 Fracture PatternsFracture patterns occur based on mode, magnitude and rate of force application to boneBending Load → transverse fx with wedge segment3-point Bend →Wedge fragment4-point Bend → Segmental fragmentTorsional Load → oblique or spiral fxAxial Load → Articular impaction (Plateau, Pilon, etc.)Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 3, 1987.
5 Fracture PatternsUnderstanding these patterns and the inherent stability of each type is important in choosing the most appropriate method of fixation and surgical approachFigure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 3, 1987.
6 Biology of Bone Healing THE SIMPLE VERSION...High Rate of HealingAbsolute Stability = 10 Bone HealingRelative Stability = 20 Bone HealingFibrous Matrix > Cartilage > Calcified Cartilage > Woven Bone > Lamellar BoneHaversian RemodelingMinimal CallusCallusSpectrum of Healing
7 Biology of Bone Healing Direct/Primary bone healingRequires rigid internal fixation and intimate cortical contact –absolute stabilityMinimal callus formationCannot tolerate fracture gapInterfragmental compression will minimize fracture motionRelies on Haversian remodeling with bridging of small gaps by osteocytes (cutting cones)Figure from: OTA Resident Course - Russel
8 Biology of Bone Healing Indirect/Secondary Bone Healing = CALLUSDivided into stagesInflammatory StageRepair StageSoft Callus StageHard Callus StageRemodeling Stage3-24 moRelative stabilityFigures from: OTA Resident Course - Russel
9 Primary/Direct Bone Healing Secondary/Indirect Bone Healing Practically speaking...Primary/Direct Bone HealingSecondary/Indirect Bone HealingSimple fracture patternsSee the fx during surgery and directly reduce and fix with:Lag screwsPlates and screwsComplex fracture patternsDon’t directly see the fracture during surgery (use fluoro)Indirectly reduce the fx and fix with:IM RodsBridge plate fixationExternal fixationCast
10 Fixation Stability Relative Stability Absolute Stability IM nailing Ex fixBridge platingCastLag screw/ plateCompression plate
11 Compression Plating/ Lag screw Spectrum of StabilityIM NailEx FixBridge PlatingCastCompression Plating/ Lag screwRelative(Flexible)Absolute(Rigid)
12 Practically speaking…. Most fixation probably involves components of both types of healing. Even in situations of excellent rigid internal fixation one often sees a small degree of callus formation...
14 Functions of Fixation Interfragmentary Compression Lag ScrewPlate FunctionsNeutralizationButtressBridgeTension BandCompressionLockingIntramedullary NailsInternal splintBridge plate fixationExternal fixationExternal splintCast*Not internal fixation
15 Indications for Internal Fixation Displaced intra-articular fractureAxial, angular, or rotational instability that cannot be controlled by closed methodsOpen fracturePolytraumaAssociated neurovascular injuryMULTIPLE REASONS EXIST BEYOND THESE...
16 Benefits of Internal Fixation Earlier functional recoveryMore predictable fracture alignmentPotentially faster time to healing
17 Screws Cortical screws: Cancellous screws: Greater number of threadsThreads spaced closer together (pitch is (smaller pitch)Outer thread diameter to corediameter ratio is lessBetter hold in cortical boneCancellous screws:Larger thread to core diameter ratioThreads are spaced farther apart (pitch is greater)Lag effect with partially-threaded screwsTheoretically allows better fixation in cancellous boneFigure from: Rockwood and Green’s, 5th ed.
18 Lag Screw Fixation Screw compresses both sides of fx together Best form of compressionPoor shear, bending, and rotational force resistancePartially-threaded screw (lag by design)Fully-threaded screw (lag by technique)
19 Lag Screws “Lag by technique” Using fully-threaded screw Step One: Gliding hole = drill outer thread diameter of screw & perpendicular to fxStep Two: Pilot hole= Guide sleeve in gliding hole & drill far cortex = to the core diameter of the screw12Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 8, 1987.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, 1987.
20 Lag ScrewsStep Three: counter sink near cortex so screw head will sit flushStep Four: screw inserted and glides through the near cortex & engages the far cortex which compresses the fx when the screw head engages the near cortexUse as sole technique of fixation is limited and advocated only in the fibula and femoral neck and unicondylar fractures.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 8, 1987.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, 1987.
21 Lag ScrewsFunctional Lag Screw - note the near cortex has been drilled to the outer diameter = compressionPosition Screw - note the near cortex has not been drilled to the outer diameter = lack of compression & fx gap maintained
22 Lag ScrewsMalposition of screw, or neglecting to countersink can lead to a loss of reductionIdeally lag screw should pass perpendicular to fxFigure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 8, 1987.Figure from: OTA Resident Course - Olsen
23 Neutralization Plates Neutralizes/protects lag screws from shear, bending, and torsional forces across fx“Protection Plate"Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, 1987.
24 Buttress / Antiglide Plates “Hold” the bone upResist shear forces during axial loadingUsed in metaphyseal areas to support intra-articular fragmentsPlate must match contour of bone to truly provide buttress effect
25 Buttress Concepts Order of fixation: Articular surface compressed with bone forceps and provisionally fixed with k-wiresBottom 3 cortical screws placedProvide buttress effectTop 2 partially-threaded cancellous screws placedLag articular surface togetherThird screw placed either in lag or normal fashion since articular surface already compressedFigure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 8, 1987.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, 1987.
26 Antiglide/Buttress Concepts Plate is secured by three black screws distal to the red fracture lineAxial loading causes proximal fragment to move distal and to the left along fracture linePlate buttresses the proximal fragmentPrevents it from “sliding”Buttress PlateWhen applied to an intra-articular fracturesAntiglide PlateWhen applied to diaphyseal fractures
27 Bridge Plates “Bridge”/bypass comminution Proximal & distal fixation Goal:Maintain length, rotation, & axial alignmentAvoids soft tissue disruption at fx = maintain fx blood supply
28 Tension Band PlatesPlate counteracts natural bending moment seen w/ physiologic loading of boneApplied to tension side to prevent “gapping”Plate converts bending forceto compressionExamples: Proximal Femur & Olecranon
29 Tension Band TheoryThe fixation on the opposite side from the articular surface provides reduction and compressive forces at the joint by converting bending forces into compressionThe fracture has tension forces applied by the muscles or load bearingJOINT SURFACETension bandLoad applied to bone
30 The tension band prevents distraction and the force is converted to compression at the joint The tension band functions like a door hinge, converting displacing forces into beneficial compressive forces at the jointJOINT SURFACETension bandLoad applied to bone
31 Classic Tension Band of the Olecranon Wires can be used for tension band as wellEx: Olecranon and patella2 K-wires from tip of olecranon across fx site into anterior cortex to maintain initial reduction and anchor for the tension wireTension wire brought through a drill hole in the ulnaBoth sides of the tension wire tightened to ensure even compressionBend down and impact wiresFigure from: Rockwood and Green’s, 4th ed.
32 Compression Plating Reduce & Compress transverse or oblique fx’s Unable to use lag screwExert compression across fracturePre-bending plateExternal compression devices (tensioner)Dynamic compression w/ oval holes & eccentric screw placement in plate
33 Examples- 3.5 mm Plates LC-Dynamic Compression Plate: stronger and stiffermore difficult to contour.usually used in the treatment radius and ulna fracturesSemitubular plates:very pliablelimited strengthmost often used in the treatment of fibula fracturesFigure from: Rockwood and Green’s, 5th ed.Figure from: Rockwood and Green’s, 5th ed.
34 Compression Fundamental concept critical for primary bone healing Compressing bone fragments decreases the gap and maintains the bone position even when physiologic loads are applied to the bone. Thus, the narrow gap and the stability assist in bone healing.Achieved through lag screw or plating techniques.
35 Plate Pre-Bending Compression Prebent plateA small angle is bent into theplate centered at the fractureThe plate is appliedAs the prebent plate compressesto the bone, the plate wants to straighten and forces opposite cortex into compressionNear cortex is compressed via standard methodsExternal devices as shownPlate hole designAlternatively a Verbrugge clamp over a screw can be similarly used to promote compression.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 9, 1987.
36 Plate Pre-Bending Compression Alternatively a Verbrugge clamp over a screw can be similarly used to promote compression.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 9, 1987.
37 Screw Driven Compression Device Requires a separate drill/screw hole beyond the plateConcept of anatomic reduction with added stability by compression to promote primary bone healing has not changedCurrently, more commonly used with indirect fracture reduction techniquesAlternatively a Verbrugge clamp over a screw can be similarly used to promote compression.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 9, 1987.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, 1987.
38 Dynamic Compression Plates Note the screw holes in theplate have a slope built intoone side.The drill hole can be purposely placed eccentrically so that when the head of the screw engages the plate, the screw and the bone beneath are driven or compressed towards the fracture site one millimeter.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p.9, 1987.This maneuver can be performed twice before compression is maximized.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, 1987.
39 Dynamic Compression Plating Compression applied via oval holes and eccentric drillingPlate forces bone to move as screw tightened = compression
40 Lag screw placement through the plate Compression can be achieved and rigidity obtained all with one constructCompression plate firstThen lag screw placed through plate if fx allowsFigure from: Rockwood and Green’s, 5th ed.
41 Locking PlatesScrew head has threads that lock into threaded hole in the plateCreates a “fixed angle” at each holeTheoretically eliminates individual screw failurePlate-bone contact not criticalCourtesy AO Archives
42 Locking PlatesMust have reduction and compression done prior to using locking screwsCANNOT PUT CORTICAL SCREW OR LAG SCREW AFTER LOCKING SCREW
43 Locking Plates Increased axial stability It is much less likely that an individual screw will failBut, plates can still break
44 Locking Plates Indications: Osteopenic bone Metaphyseal fractures with short articular blockBridge plating
45 Intramedullary Nails Relative stability Intramedullary splint Less likely to break with repetitive loading than plateMore likely to be load sharing (i.e. allow axial loading of fracture with weight bearing).Secondary bone healingDiaphyseal and some metaphyseal fractures
46 Intramedullary Fixation Generally utilizes closed/indirect or minimally open reduction techniquesGreater preservation of soft tissues as compared to ORIFIM reaming has been shown to stimulate fracture healingExpanded indications i.e. Reamed IM nail is acceptable in many open fractures
47 Intramedullary Fixation Rotational and axial stability provided by interlocking boltsReduction can be technically difficult in segmental and comminuted fracturesMaintaining reduction of fractures in close proximity to metaphyseal flare may be difficult
48 Open segmental tibia fracture treated with a reamed, locked IM Nail. Note the use of multiple proximal interlocks where angular control is more difficult to maintain due to the metaphysealflare.
49 Intertrochanteric/Subtrochanteric fracture treated with closed IM NailThe goal:Restore length, alignment, and rotationNOT anatomic reductionWithout extensiveexposure this fracture formed abundant callus by 6 weeksValgus is restored...
50 Reduction Techniques…some of the options Indirect MethodsDirect MethodsTraction-assistant, fx table, intraop skeletal tractionDirect external force i.e. push on itPercutaneous clampsPercutaneous K wires/Schantz pins—”Joysticks”External fixator or distractorIncision with direct fracture exposure and reduction with reduction forceps
51 Reduction TechniquesOver the last 25 years the biggest change regarding ORIF of fractures has probably been the increased respect for soft tissues.Whatever reduction or fixation technique is chosen, the surgeon must minimize periosteal stripping and soft tissue damage.EXAMPLE: supraperiosteal plating techniques
52 Direct Reduction Technique Pointed reduction clamps used to reduce a complex distal femur fractureOpen surgical approachExcellent access to the fracture to place lag screws with the clamp in placeRemember, displaced articular fractures require direct exposure and reduction because anatomic reduction is essential
53 Reduction Technique - Clamp and Plate Place clamp over bone and the plateMaintain fracture reductionEnsure appropriate plate position proximally and distally withrespect to the bone, adjacent joints, and neurovascular structuresEnsure that the clamp does not scratch the plate, otherwise thecreated stress riser will weaken the plateFigure from: Rockwood and Green’s, 5th ed.
54 Percutaneous Plating Plating through modified incisions Indirect reduction techniquesLimited incision for:Passing and positioning the plateIndividual screw placementSoft tissue “friendly”
55 Failure to Apply Concepts Classic example of inadequate fixation & stabilityNarrow, weak plate that is too shortInsufficient cortices engaged with screws through plateGaps left at the fx siteUnavoidable result = NonunionFigure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, New York, p. 320, 1987.Figure from: Schatzker J, Tile M: The Rationale of Operative Fracture Care. Springer-Verlag, 1987.
56 Summary Respect soft tissues Choose appropriate fixation method Achieve length, alignment, and rotational control to permit motion as soon as possibleUnderstand the requirements and limitations of each method of internal fixationIf you would like to volunteer as an author for the Resident Slide Project or recommend updates to any of the following slides, please send an toOTAaboutQuestions/CommentsReturn toGeneral/PrinciplesIndex