David Sanders MD, MSc, FRCSC

London Health Sciences CentreUniversity of Western Ontario London, Ontario, Canada

Created March 2004; Revised August 2006 Revised May 2011

Fractures of the Talus and Subtalar Dislocations

Outline:Talar Neck FracturesAnatomyIncidenceImagingClassificationManagementComplicationsTalar body, head and process fractures

Subtalar dislocationsClassificationManagement Outcomes

Surface 60% cartilageNo muscular insertionsAnatomy

Blood Supply4 primary arterial sources:Artery of tarsal canalArtery of tarsal sinusDorsal neck vesselsDeltoid branchesmediallateralInferior view of talus, showing vascular anastomosis

VascularityArtery of tarsal canal supplies majority of talar bodySide ViewTop ViewDeltoid BranchesPosterior tuberclevesselsArtery of TarsalSinusArtery ofTarsal CanalSuperior Neck VesselsSuperior Neck VesselsArtery of TarsalSinusArtery ofTarsal CanalPosterior tuberclevessels

Talus ORIF TechniqueVascularity

Talus ORIF Technique

Incidence2 % of all fractures6-8% of foot fracturesHigh complication ratesavascular necrosispost-traumatic arthritismalunion

Mechanism of InjuryHyperdorsiflexion of the foot on the leg

Neck of talus impinges against anterior distal tibia, causing neck fractureIf force continues:talar body dislocates posteromedialoften around deltoid ligament

Injury MechanismPreviously called aviators astragalus

Usually due to motor vehicle accident or falls from height

Approximately 50 % of patients have multiple traumatic injuries

BiomechanicsTheoretical shear force across talar neck:1200 N during active motion [Swanson 1992]Fracture fixation must withstand this force to permit active motion in the postoperative phase

ImagingComplex 3-D structureMultiple plain film orientations:AP, Lateral, Broden, & mortise views demonstrates joint congruity of ankle and subtalar jointCanale view for longitudinal alignment: approximately 15 IR to get calcaneous out of view

Canale View

Canale ViewSlight ankle plantarflexion with knee bent to rest foot on the table15 degree pronationXray Tube 15 degree from vertical

Canale View

CT ScanMost useful assessment tool for surgical planningConfirms displacementDemonstrates subtalar joint reduction, comminution, osteochondral fractures/debris

MRI ScanPrimary role in talus injuries is to assess complications, especially avascular necrosisMay be poor quality if extensive hardware presentZone of osteonecrosis following distribution of Artery of Tarsal Canal

Talar Neck Fractures: ClassificationHawkins, 1970

Predictive of AVN rate

Widely used

Talus ORIF TechniqueHawkins ClassificationHawkins, LR, JBJS, 52A: 991, 1970Nondisplaced

Hawkins 1Type I: undisplacedAVN rate 0 13 %

Uncommon as most talar neck fractures are displaced

Hawkins 2Displaced fracture with subtalar subluxation / dislocation

A)fracture line enters subtalar jointB) subtalar joint intact

AVN 20 50 %Most common type

Hawkins 3Subtalar and ankle joint dislocatedTalar body extrudes, usually around deltoid ligamentCommonly open fractures, reduction very difficultClosed: plantar flex foot & flex kneeOpen: joy sticksAVN 83 100 %

Hawkins 4Added to classification by Canale, 1974Incorporates talonavicular subluxationRare variantComplex talar neck fractures which otherwise do not fit classification are included as Type 4 injuries

Classification:Comminution:An important additional predictor of results, especially regarding prognosis re:MalunionSubtalar joint arthritis

Included in AO-OTA classification as a modifier

Goals of ManagementImmediate reduction of dislocated jointsVascularityCutaneous tensionVascular compromiseAnatomic fracture reductionStable fixationFacilitate unionAvoid complications

Talus ORIF TechniqueDefinitive TreatmentPrompt anatomic operative reductiondie is cast with injuryUse joy stick K-wires for reductionArticular bone affects ROM (V, Sup, PF)Maintenance of reduction with HWScrews (AP, PA), countersinkPlates (2.0 mini condylar or T)Dual incisionsDo not dissect capsular attachmentsMaintain as much soft tissue attachments

Talus ORIF Technique

Treatment of Talar Neck FracturesEmergent reduction of dislocated jointsStable internal fixation Debridement of subtalar jointMaintain as much soft tissue/vascular attachmentsChoice of fixation and approach depends upon personality of fracture

Treatment of Talar Neck FracturesPost operative rehabilitation:Sample protocol:Initial immobilization, 2-6 weeks depending upon soft tissue injury and patient factors, to prevent contractures and facilitate healingNon weight-bearing, Range of Motion therapy until 3 months or fracture union

Hawkins I FractureOptions:Non Operative & Non-Weight-Bearing Cast for 4-6 weeks followed by removable brace and motionOR:Percutaneous screw fixation and early motion

Hawkins II, III, and IV Fractures:Results dependent upon development of complicationsOsteonecrosisMalunionArthritis

Case Example29 yo maleATV rolloverIsolated injury LLE

These injury films are tough to interpret, but close review demonstrates the dislocated talar body with some comminution.

DiagnosisHawkins 3 talar neck fractureAssociated comminution, probably involving medial column and subtalar joint

Controversies for this Case:Surgical timingClosed reductionSurgical approachFixation

Surgical TimingIn general: emergent reduction of dislocated joints

Allow life threatening injuries to take priority and resuscitate adequately first

Closed Reduction?May be very useful, particularly if other life threatening injuries preclude definitive surgeryDifficult in Hawkins 3 and 4 injuries

Closed Reduction Technique:Adequate sedationFlex knee to relax gastrocsTraction on plantar flexed forefoot to realign head with bodyVarus/valgus correction as necessaryDirect pressure on talar bodyAdjunct: traction pin, general anesthetic, etcAvoid repetitive reduction attempts in order to avoid skin compromise or tearing

Closed Reduction Example

External FixationLimited roles:Multiply injured patient with talar neck fracture in whom definitive surgery will be delayedTemporizing measure to stabilize reduced joints Construct bridges tibia calcaneus midfoot

Surgical Approaches: Options1 incision techniques:Anteromedial orAnterolateral

Problem: difficult to visualize the entire talar neck and subtalar joint without significant soft tissue stripping and devascularizationProblem: usual medial comminution inhibits accurate read of fracture reduction

Surgical Approaches: Options2 incision technique: (generally preferred)Anteromedial and lateral/anterolateral

Problem: 2 skin incisions, close togetherBenefit: excellent fracture visualization at critical sites of reduction and subtalar joint with less stripping

1st Approach: Anteromedial Medial to TibAntMake incision more posterior for talar body fractures to facilitate medial malleolar osteotomy

1st Approach: AnteromedialProvides view of neck alignment and medial comminutionExtend incision distally to talonavicular joint hardware is placed distal to proximal and needs to be well countersunk to avoid impingement

2nd Approach: LateralTip of Fibula directly anteriorMobilize EDB as sleeveProtect sinus tarsi contents

2nd Approach: LateralVisualizes Anterolateral alignment and subtalar jointFacilitates Placement of Shoulder Screw or lateral plate

2 incisions: Skin bridgeNarrow skin bridge but generally well toleratedTalus fractures generally have less soft tissue problems compared to plafond or calcaneus fractures

Fixation OptionsStable Fixation to allow early motion is the goal1200 N stress across talar neck during early motion (Swanson JBJS 1992)That is a lot of force! 2 A to P screws only resists about 1 kN of stress so need more fixation

Surgical Tactics: FixationAnteriorPartial threaded screwsFully threaded screwsMini-fragment plates (2.0, 2.4 mm)PosteriorLag screwsImplant selection depends upon injury, degree of comminution, bone quality

Posterior to Anterior Fixation:Screw fixation stronger from posterior than from anteromedial (T Bray)Screws perpendicular to fracture site 2 PA screws in compression are able to withstand the theoretical shear force of active motionAvoid excessive posterior capsular strippingCreates potentially 3 incisions (posterior, medial, lateral)

Anterior Screw Fixation:Screw fixation alone is acceptable for non-comminuted fractures, but consider adding a plate if there is comminution. Easy to insert under direct visualization This example: displaced type 2: 4 A-P screws including medial buttress fully threaded cortical screws and lateral shoulder screws

Anterior Screw Fixation:This example: 4.0 mm partially threaded compression screws through non-comminuted columnsMini-fragment (2.4 mm) screws for osteochondral fragmentsConsider Titanium for MRI

Plate Fixation:Very useful in comminuted fractures:2.0 or 2.4 mm plates Easiest to apply to lateral cortex impinge on medial side

Talus ORIF TechniqueHawkins 3

Talus ORIF Technique

Talus ORIF Technique

Talus ORIF Technique

ComplicationsAVNMalunion

NonunionArthritis

Talus ORIF TechniqueResultsChateau, Indy, 2002 JOT23 pts, 20 mo F/UDual, mini fragmentLow rate AVN Elgafy, Foot Ankle 200060 fxArthritis:Ankle 25%, Subtalar 53%AVN 16%Harborview, 2002 OTA60 fx, 30 mo F/Uw/in 24 hr (40 pts)/Dual 91%Worse results with:ComminutionOpenOsteonecrosis39% (II) 56% to collapse64% (III) 67% to collapse

AVN: Incidence after Talus FractureCanale (1972): I: 15 %II: 50 %III: 85 %IV: 100 %Behrens (1988):Overall 25 %Ebraheim/Stephen(2001):Overall 20 %

Talus ORIF TechniqueAVASCULAR NECROSIS Rates with Hawkins ClassAVN does not = poor result? MRI-probably not prognostic ? Does early ORIF minimize AVN

Talus ORIF Technique

AVN: DiagnosisHawkins Sign: Xray finding 6-8 weeks post injuryPresence of subchondral lucency implies revascularization

AVN: ImagingPlain radiographs: sclerosis common, decreases with revascularizationMRI: very sensitive to decreased vascularity

Talus ORIF TechniqueHawkins 3

Talus ORIF Technique

Talus ORIF Technique1 year follow-up|Osteonecrosis without collapse

Talus ORIF Technique

Bilateral Injuries Fixed at 72 hours

2 years Pain, Stiffness, LimpHawkins IIIHawkins II

AVN Treatment:Precollapse:Modified WBPTB castCompliance difficultEfficacy unknown

Postcollapse:ObservationBlair fusion is one option if symptomatic

Malunion: IncidenceCommon: up to 40%

Most often Varus

Malunion: DiagnosisVarus hindfoot, midfoot supination on clinical exam

Dorsal malunion on Xray

MalunionMechanical effects> 3 degrees malunion: decreased subtalar ROM (Daniels TR, JBJS 1996)> 2mm: altered subtalar contact forces (Sangeorzan J Orthop Res 1992)

Clinical Effect of MalunionMalunion:More painLess satisfactionLess ankle motionWorse functional outcome

Malunion Rx:Talus osteotomyCalcaneus osteotomyPossible midfoot osteotomyTendo Achilles Lengthening

Talus ORIF TechniqueArthrosis (Subtalar)Pain &/or stiffness 16 (52%)Dx arthrosis 6 (19%)Subtalar arthrodesis 3 (10%)

Talus ORIF Technique

Post Traumatic ArthritisIncidence of post-traumatic arthritis30-90 %

Post-Traumatic ArthritisMost commonly involves Subtalar joint

Rx: Arthrodesis

NonunionUncommon, even with AVN

Delayed Union very common

Frequently results in late malalignment

Talar Body FracturesTreatment strategy and outcomes similar to talar neck fracturesMedial or Lateral Malleolar Osteotomy frequently required

Medial Malleolar OsteotomyPredrill and pretap malleolusOsteotomy aims just off the medial corner of mortise to facilitate interdigitationChevron, straight, or stepcut techniquesOsteotome to crack cartilage helps avoid mortise malalignment

Talar Body + Fibula FractureVisualize body through the fibula fracture

Talar Body Case Example58 year old female4 week old fractureMissed initially

Case, contdExtensive comminution into subtalar jointPoor bone quality

Selected Rx: Primary ArthrodesisTricortical bone graft to reconstitute talar height

Osteochondral InjuriesFrequently encountered with talus neck and body fracturesRequire small implants for fixationExcise if unstable and too small to fix

Osteochondral Injuries

Osteochondral Fragment RepairLarge fragment repaired, small fragment excised

Talar Head and Process FracturesTreat according to injuryOperate when associated with joint subluxation, incongruity, impingement or marked displacementFragments often too small to fix and require excision

Case Example: Talar Head FractureTalar head injurySubtle on plain x-ray

Talar Head Fracture, continuedCT demonstrates subtalar injury and subluxation

Treatment of Talar Head FractureRequired 2 incisions to debride subtalar joint from lateral approach, and reduce / stabilize fracture from medial side

Lateral Process ExampleUsually require CT scanOften excised due to size of fragments Difficult to achieve union

Lateral Talar Process FracturesSnowboarders fractureMechanism: may occur from inversion (avulsion injury) or eversion and axial loading (impaction fracture)Often misdiagnosed as ankle sprainBest results if treated early, either by immobilization, ORIF or fragment excisionIf diagnosed late consider fragment excision as attempts to achieve union often fail

Talus Fracture AO/ASIF ClassificationLateral Process (81-A2.1)

Treatment OptionsNon-operatively for minimally displaced fractures

Excision of fragment

Isolated mini fragment screws

Mini plate fixation

Fracture ComplicationsExtend into subtalar joint

Accelerated post-traumatic arthritis pain stiffness disability subsequent surgery for subtalar joint fusion

Mini Plate ProcedureLateral approachSubtalar chondral debris removedImpaction elevated if present & filled with allograft if requiredPreliminary 0.45 Kirschner wire (K-wire) fixation.2.0 mm T plate applied upside downLag screw fixation - avoiding overcompression with comminution

Talar FractureIsolated Lateral Process

Talus FractureLateral Process & Talar NeckMarginal ImpactionComminuted Fracture

Posterior Talar Process Fracture2 components: medial and lateral tubercleGroove for FHL tendon separates the two tuberclesDifferentiate fracture from os trigonum well corticated, smooth oval or round structure

Posterior Talar Process FracturesMedial tubercle fracture: Cedells fractureLateral tubercle: Shepherds fracture

Treatment: immobilize or excise or ORIF

TreatmentUsually associated with Talar Neck FxPosteromedial Approach behind Neurovascular BundleMedial Malleolar Osteotomy usually not effective for exposure or fixation

Example 18 yo Car Surfer

CT Evaluation

Treatment 3 Incisions

Subtalar DislocationsSpectrum of injuries

Relatively Innocent

Very Disabling

ClassificationUsually based upon direction of dislocation:

Medial dislocation: 85 %, low energyLateral dislocation: 15 %, high energy

Other Important Considerations:Open vs Closed

High or low energy mechanism

Stable or unstable post reductionReducible by closed means or requiring open reduction

Associated impaction injuriesAll have prognostic significance:

Important Distinction:Total talar dislocation, or pan talar dislocationResults from continuation of force causing subtalar dislocationHigh risk of AVN, usually open, poor prognosisOpen pantalar dislocation with skin loss showing Incongruent reduction: Result was AVN and pantalar fusion

Management of Subtalar DislocationUrgent Closed reduction:Adequate sedationKnee flexionLongitudinal foot tractionAccentuate, then reverse deformity

Successful in up to 90 % of patients

Open Reduction:More likely after high energy injuryMore likely with lateral dislocationCause:soft tissue interposition (Tib post, FHL, extensor tendons, capsule)bony impaction between the talus and navicular

Rehabilitation:Stable injuries: 4 weeks immobilizationPhysio for mobilizationUnstable injuries:Usually dont require internal fixation once reduction achievedIf necessary external fixation or transarticular wire fixation

Outcome of Subtalar Dislocations:Less benign than previously thoughtSubtalar arthritis:Up to 89 % radiographicallySymptomatic in up to 63 %Ankle and midfoot arthritis less common

Summary:Talar Neck FracturesAnatomyIncidenceImagingClassificationManagementComplicationsTalar body, head and process fractures

Subtalar dislocationsClassificationManagement Outcomes

Selected ReferencesHawkins LG 1970 Fractures of the neck of the talus. J Bone Joint Surg Am 52(5):991-1002.Canale ST, Kelly FB, Jr. 1978 Fractures of the neck of the talus. Long-term evaluation of seventy-one cases. J Bone Joint Surg Am 60(2):143-56.the two classics on talus fractures. Rates of AVN, classification, etc. Good descriptive papers.Additional Clinical papers:Elgafy H, Ebraheim NA, Tile M, Stephen D, Kase J 2000 Fractures of the talus: experience of two level 1 trauma centers. Foot Ankle Int 21(12):1023-9.Metzger MJ, Levin JS, Clancy JT 1999 Talar neck fractures and rates of avascular necrosis. J Foot Ankle Surg 38(2):154-62.Pajenda G, Vecsei V, Reddy B, Heinz T 2000 Treatment of talar neck fractures: clinical results of 50 patients. J Foot Ankle Surg 39(6):365-75.

Selected ReferencesRecent Literature:Sanders DW, Busam M, Hattwick E, Edwards JR, McAndrew MP, Johnson KD. Functional outcomes following displaced talar neck fractures. J Orthop Trauma 2004; 18: 265-270.Vallier HA, Nork SE, Barei DP, Benirschke SK, Sangeorzan BJ. Talar neck fractures: results and outcomes. J Bone Joint Surg 2004; 86-A: 1616-1624.-Good outcome papers on talar neck

Fleuriau Chateau PB, Brokaw DS, Jelen BA, Scheid DK, Weber TG. Plate fixation of talar neck fractures: preliminary review of a new technique in twenty-three patients. J Orthop Trauma. 2002;16(4):213-9.-plate fixation discussed Vallier HA, Nork SE, et al. Surgical treatment of talar body fractures. J Bone Joint Surg 2004; Supp 1: 180-92; and 2003; 85-A: 1716-24- good talar body review and surgical technique Bibbo C, Anderson R, Marsh WH. Injury characteristics and the clinical outcome of subtalar dislocations: a clinical and radiographic analysis of 25 cases. Foot ankle int 2003: 24: 158-63.-best current info on subtalar dislocations

References Cont.BiomechanicsSangeorzan BJ, Wagner UA, et al. Contact characteristics of the subtalar joint: the effect of talar neck misalignment. J Orthop Res 1992; 10(4): 544-51.Daniels TR, Smith JW, Ross TI. Varus malalignment of the talar neck. Its effect on the position of the foot and on subtalar motion. J Bone Joint Surg Am. 1996; 78: 1559-67.Swanson TV, Bray TJ, Holmes GB Jr. Fractures of the talar neck. A mechanical study of fixation. J Bone Joint Surg Am 1992; 74(4): 544-51.Attiah M, Sanders DW et al. Comminuted talar neck fractures: a mechanical study of fixation techniques. J Ortho Trauma 2007; 21: 47-51.

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*Thank you

This project was performed at the Vanderbilt University Medical Centre With the collaboration of Matt Busam, Emily Hattwick, Ken Johnson and Mark McAndrew.*************Fractures of the talar neck are difficult injuries. While complications are frequent, the exact incidence is unclear from the literature. Depending upon the study, osteonecrosis rates have varied from 10 to 100 per cent in displaced fractures. Similarly, the incidence of post traumatic arthritis can vary greatly.

The variations in reported outcomes are multifactorial but have led to difficulty in predicting a result for an individual patient.

*The incidence of post traumatic arthritis, for example, varies from 30 to 90 per cent depending upon whether one is relying upon radiographic, clinical or functional outcome measures.

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While these outcome measures are important, it would be useful to know what the likelihood of requiring salvage surgery such as a subtalar fusion is. Use of a hard endpoint such as the need for secondary surgery can identify patients with a worse outcome, and allow us to compare and evaluate causes of treatment failure.