SUMMARY

• Ankle fractures are very common injuries to the ankle which generally occur due to a twisting mechanism.

• Diagnosis is made with plain radiographs of the ankle.

• Treatment can be nonoperative or operative depending on fracture displacement, ankle stability, presence of syndesmotic injury, and patient activity demands.  

EPIDEMIOLOGY 

• Incidence

  • 187 per 100,000 adults annually

• Demographics

  • bimodal distribution

    • young, active 

      • highest incidence in male is between 15-24 years of age

    • elderly 

      • highest incidence in females is 75-84 years of age

• Location

  • breakdown by fracture type

    • isolated malleolus fracture 70%

    • bimalleolar 20%

    • trimalleolar 7%

• Risk Factors 

  • male 

  • younger age

  • obesity

  • smoking 

  • alcohol consumption

ETIOLOGY

• Pathophysiology

  • mechanism of injury 

    • twisting injury 

• Associated conditions

  • orthopedic 

    • open fractures (2%)

    • syndesmotic injury (10%)

    • chondral injury 

    • peroneal tendon tears (4%)

ANATOMY

• Osteology

  • modified hinge joint consisting of tibia, fibula, and talus

  • tibial plafond and talus are broader anteriorly and wider laterally

• Ligaments

  • 3 ligamenotus complex stabilize ankle 

    • deltoid 

      • 2 components

        • superficial 

          • extends from medial malleolus to broad insertion onto navicular, sutentaculum tali, and talus

          • resists hindfoot eversion

        • deep

          • extends from medial malleolus to talus

          • resists ER of talus

    • lateral ligament complex 

      • 3 components

        • anterior talofibular ligament (ATFL)

          • primary restraint to anterior displacement, IR, and inversion of talus

          • most frequently injured lateral ligament

        • calcaneofibular (CFL)

          • deep to peroneal tendons

          • 2nd most commonly injured 

        • posterior talofibular ligament (PTFL)

          • strongest ligament of lateral complex and least likely to be disrupted

    • syndesmosis  

      • 5 components 

         

        • anterior inferior tibiofibular ligament (AITFL)

          • originates from anterolateral tubercle of distal tibia (Chaput)

          • inserts anteriorly onto lateral malleolus (Wagstaffe)

        • posterior inferior tibiofibular ligament (PITFL)

          • broad origin from posterior tibia (Volkmann's fragment) 

          • inserts onto posterior aspect of lateral malleolus 

          • strongest component of syndesmosis 

        • intraosseous ligament (IOL)

          • distal continuation of intraosseous membrane

        • intraosseous membrane

        • inferior transverse ligament (ITL)

• Tendons

  • peroneal tendons

    • peroneus longus and brevis pass along posterior groove of lateral malleolus

    • at risk with posterolateral fibular plating 

  • posterior tibial tendon 

    • located posterior and inferior at the level of the medial malleolus

    • at risk with posterior placement of medial malleolus screws 

• Neurovascular structures

  • anterior tibial artery and deep peroneal nerve

    • course over anterior ankle between EDL and EHL

    • at risk with anterior approach 

  • posterior tibial artery and tibial nerve

    • course posterior to medial malleolus between FDL and FHL

    • at risk with posteromedial approach

  • superficial peroneal nerve

    • crosses anteriorly over fibula about distal 1/3 

    • at risk with posterolateral and direct lateral approach to fibula proximally and with anterior/anterolateral approaches

  • sural nerve

    •  at risk with posterolateral and direct lateral approach to fibula 

• Biomechanics

  • deltoid ligament (deep portion)

    • primary restraint to anterolateral talar displacement

  • fibula

    • acts as buttress to prevent lateral displacement of talus

  • trapezoidal shape of talus  

    • dorsiflexion results in fibula ER and lateral translation, accommodating anteriorly wider talus

    • plantarflexion results in narrower, posterior aspect of the talus leading to IR of talus

CLASSIFICATION

• Lauge-Hansen 

   

  • based on combination of foot position and direction of force applied at the time of injury

  • has been shown to predict the observed (via MRI) ligamentous injury in less than 50% of operatively treated fractures

• Lauge-Hansen Classification
  Supination - Adduction (SAD)	1. Talofibular sprain or distal fibular avulsion 2. Vertical medial malleolus and impaction of anteromedial distal tibia
  Supination - External Rotation (SER)	1. Anterior tibiofibular ligament sprain 2. Lateral short oblique fibula fracture (anteroinferior to posterosuperior) 3. Posterior tibiofibular ligament rupture or avulsion of posterior malleolus 4. Medial malleolus transverse fracture or disruption of deltoid ligament
  Pronation - Abduction (PAB)	1. Medial malleolus transverse fracture or disruption of deltoid ligament 2. Anterior tibiofibular ligament sprain 3. Transverse comminuted fracture of the fibula above the level of the syndesmosis
  Pronation - External Rotation (PER)	1. Medial malleolus transverse fracture or disruption of deltoid ligament 2. Anterior tibiofibular ligament disruption 3. Lateral short oblique or spiral fracture of fibula (anterosuperior to posteroinferior) above the level of the joint 4. Posterior tibiofibular ligament rupture or avulsion of posterior malleolus

• Danis-Weber (location of fibular fracture)

  • A - infrasyndesmotic (generally not associated with ankle instability)

  • B - transsyndesmotic

  • C - suprasyndesmotic

• AO / OTA

  • 44A - infrasyndesmotic

  • 44B - transsyndesmotic

  • 44C - suprasyndesmotic

• Anatomic / Descriptive

  • isolated medial malleolar

  • isolated lateral malleolar

  • isolated posterior malleolar

  • bimalleolar-equivalent

  • bimalleolar 

  • trimalleolar

• Variants

  • Bosworth fracture-dislocation

  • hyperplantarflexion injury (6%)

  • curbstone fracture

    • avulsion fracture of posterior tibia resulting from tripping

  • LeFort–Wagstaffe fracture 

    • AITFL avulsion off anterior fibular tubercle usually seen with SER-type fracture patterns

  • Tillaux–Chaput fracture

    • AITFL avulsion of anterior tibial margin (tibial counterpart of LeFort–Wagstaffe fracture)

PRESENTATION

• Symptoms

  • severe ankle pain 

  • difficulty or inability to ambulate

• Physical exam

  • inspection and palpation

    • ecchymosis and swelling around the ankle 

      • medial sided swelling, tenderness, and ecchymosis not sensitive for medial stability  

    • deformity with displaced fractures

    • palpate proximal fibula for Maisonneuve fracture 

    • soft tissue assessment 

      • soft tissue injury

        • fracture blisters 

        • skin tenting 

        • open wounds

  • motion

    • ankle motion generally limited 

  • neurovascular

    • peripheral vascular disease

    • diabetic neuropathy 

IMAGING

• Radiographs

  • recommended views

    • ankle series 

      • AP

      • lateral

      • mortise 

    • dynamic stress views

      • manual stress view 

        • most appropriate stress radiograph to assess competency of deltoid ligament 

           

          • assess on mortise view 

          • foot dorsiflexed and ER with tibia stabilized

        • more sensitive to injury than medial tenderness, ecchymosis, or edema 

           

      • gravity stress radiograph is equivalent to manual stress radiograph 

    • full-length tibia radiographs

      • rule out Maisonneuve-type fracture

  • optional

    • comparison view of contralateral ankle

    • weight bearing views

      • difficult for patients to tolerate in acute setting

  • findings

    • syndesmotic injury

      • decreased tibiofibular overlap 

        • measure at point of maximum overlap

        • normal >6 mm on AP view

        • normal >1 mm on mortise view

        • it has also been reported that there is no actual correlation between syndesmotic injury and tibiofibular clear space or overlap measurements

      • increased medial clear space 

        • normal ≤ 4 mm on mortise or stress view

        • medial clear space of >5mm with external rotation stress applied to a dorsiflexed ankle is predictive of deep deltoid disruption

      • increased tibiofibular clear space 

        • measure clear space 1 cm above joint 

           

        • normal <6 mm on both AP and mortise views

    • lateral malleolus fractures

      • talocrural angle 

        • bisection of line through tibial anatomical axis and line through tip of both malleoli

        • shortening of lateral malleoli fractures can lead to increased talocrural angle 

           

        • talocrural angle is not 100% reliable for estimating restoration of fibular length

        • can also utilize realignment of the medial fibular prominence with the tibiotalar joint

    • posterior malleolus fractures

      • double contour sign 

      • misty mountains sign 

      • spur sign

• CT scan 

  • indications

    • trimalleolar ankle fracture 

      • operative planning  

        • 25% of surgeons would change operative technique after CT

      • assess morphology of posterior malleolus 

    • supination-adduction injury

      • assess for anteromedial impaction of tibial plafond and talar articular cartilage injury  

         

  • views

    • axial and sagittal views most useful to assess posterior malleolus 

  • findings

    • size and shape of posterior malleolus fragment

    • entrapped loose fragments 

    • impaction

    • comminution 

• MRI

  • Indications

    • evaluate for soft tissue or cartilaginous injuries

  • findings

    • deltoid injury

    • syndesmotic injury

    • lateral ankle ligament complex

    • peroneal tendon injury 

    • chondral lesions of talus 

DIFFERENTIAL

• Ankle sprain 

  • may be able to bear weight

  • positive anterior drawer or talar tilt test 

  • radiographs without fracture 

• Syndesmotic injury

  • positive Hopkin's squeeze test

  • increased medial clear space or tibiofibular diastasis on stress view

  • lambda sign on MRI

• Achilles tendon rupture 

  • palpable gap over achilles

  • inability or weakness with plantar flexion 

  • increased resting dorsiflexion when prone with knees bent

  • positive Thompson's test

• Pilon fracture 

  • high energy, axial load 

  • significant articular involvement 

  • CT showing 4 common components of pilon

    • Chaput fragment, Volkmann fragment, medial malleolus, central impaction 

• Subtalar dislocation

  • high energy with extensive soft tissue injury, 25% open

  • x-ray shows dislocation of talus from calcaneous or navicular bone

TREATMENT

• Nonoperative

  • indications

    • stable ankle fracture

      • isolated stable medial malleolus fracture 

      • isolated stable lateral malleolus fracture

      • avulsion tip fractures of medial or lateral malleolus 

      • posterior malleolar fracture with < 25% joint involvement or < 2mm step-off

    • unfit for surgery

  • modalities

    • short-leg AO splint

    • short-leg cast

    • CAM boot

• Operative

  • open reduction internal fixation

    • indications

      • any talar displacement

      • bimalleolar or bimalleolar-equivalent fracture

      • posterior malleolar fracture with > 25% or > 2mm step-off 

         

      • Maisonneuve fracture 

      • Bosworth fracture-dislocations

      • open fractures

      • symptomatic malleolar nonunions

    • technique

      • goal of treatment is stable anatomic reduction with restoration of mortise 

        • see fracture patterns below for specific treatment

      • positioning

        • supine

          • direct reduction of medial and lateral malleolus fractures 

          • indirect reduction of posterior malleolus 

          • syndesmotic fixation 

        • prone or lateral 

          • facilitates direct reduction of posterior malleolus

      • approach

        • direct lateral approach to fibula

          • common approach for fibula ORIF syndesmotic fixation 

          • syndesmotic fixation 

        • posterolateral approach to ankle

          • concomitant access to posterior fibula and posterior malleolus 

          • prone or lateral 

        • posteromedial approach to ankle

          • access to medial malleolus and posterior malleolus 

        • direct medial approach to ankle

          • common approach for medial malleolus ORIF

    • outcomes

      • overall success rate of 90%

        • prolonged recovery expected (2 years to obtain final functional result)

      • anatomic reduction is considered most important factor for satisfactory outcome 

         

        • 1 mm shift of talus leads to 42% decrease in tibiotalar contact area 

      • worse outcomes associated with:

        • decreased level of education

        • smoking

        • alcohol use

        • presence of medial malleolar fracture

      • ORIF superior to closed treatment of bimalleolar fractures

      • restoration of marginal impaction of tibial plafond in SA ankle fracture leads to optimal functional outcomes 

         

      • improved incisional perfusion with Allgöwer-Donati sutures  

         

    • postoperative rehabilitation

      • proper braking response time (driving) returns to baseline at 9 weeks after surgery  

         

      • braking travel time is significantly increased until 6 weeks after initiation of weight bearing in both long bone and periarticular fractures of lower extremity 

         

  • external fixation

    • indications 

      • staging procedure

        • severe open fractures with gross contamination 

        • poor soft tissue requiring close monitoring 

      • unstable reduction 

    • modalities

      • ankle-spanning external fixator

      • circular frame

      • hybrid 

    • outcomes

      • lower risk of redislocation and skin complication in ankle fracture dislocation vs splint 

ISOLATED MEDIAL MALLEOLUS FRACTURE

• Nonoperative

  • indications

    • isolated medial malleolus fracture without talar shift  

    • avulsion tip fracture 

      • deep deltoid inserts on posterior colliculus

  • technique

    • NWB for 4-6 weeks

  • outcomes

    • good outcomes with >95% union rate for isolated injury 

• Operative

  • ORIF

    • indications

      • any talar shift (static or stress view)

    • technique

      • lag screw fixation

        • lag screw fixation stronger if placed perpendicular to fracture line

      • antiglide plate with lag screw

        • best for vertical shear fractures 

           

          • biomechanically superior to unicortical/bicortical screw fixation alone 

      • tension band fixation

        • fragment too small 

        • poor bone quality 

    • outcomes

      • bicortical 3.5 mm fully-threaded screw (lag by technique) superior to unicortical 4.0 mm partially-threaded screw (lag by design) 

ISOLATED LATERAL MALLEOLUS FRACTURE

• Nonoperative

  • indications

    • stable mortise with no talar shift

      • > 4-5 mm of medial clear space widening on stress views considered unstable 

        • recent studies show deep deltoid intact with 8-10 mm of widening on stress view

  • technique

    • immediate WBAT in CAM boot

    • brief period of immobilization in splint

• Operative

  • open reduction and internal fixation (ORIF) 

     

    • indications

      • presence of talar shift on static or stress view (bimalleolar equivalent)

      • >3 mm displacement  

    • technique

      • plate

        • lateral

          • one-third tubular or anatomic distal fibular plate

          • stiffest fixation construct for the fibula is a locking plate 

             

        • posterolateral

          • one-third tubular plate (antiglide mode) 

            • posterior antiglide plating is biomechanically superior to lateral plate

          • disadvantage of peroneal tendon irritation if plate too distal 

             

      • retrograde intramedullary fixation  

        • several implant choices

          • newer implants have improved axial and rotational control with distal/proximal fixation 

        • useful for poor soft-tissue envelopes or high risk for wound-healing complication

    • outcomes 

      • similar outcomes with operative and non-operative treatment if stable mortise

 BIMALLEOLAR-EQUIVALENT FRACTURE (DELTOID LIGAMENT TEAR WITH FIBULAR FRACTURE)

• Nonoperative

  • indications

    • low demand and unable to tolerate surgery 

• Operative

  • ORIF of lateral malleolus +/- syndesmotic fixation 

    • indications

      • lateral malleolus fracture with talar shift (static or stress view)

    • technique

      • assess syndesmotic stability after fixation of lateral malleolus   

      • not necessary to repair medial deltoid ligament

      • explore medially if unable to reduce mortise and deltoid ligament potentially interposed 

    • outcomes

      • lower rate of nonunion and fracture displacement with operative treatment  

BIMALLEOLAR (MEDIAL AND LATERAL)  FRACTURE

• Nonoperative

  • indications

    • low demand and unable to undergo surgical intervention

• Operative

  • ORIF

    • indications

      • any displacement or talar shift (static or stress view) 

    • fibula technique

      • lateral plate

      • posterolateral plate

      • retrograde intramedullary fixation 

    • medial malleolus technique

      • antiglide plate  

         

      • tension band wiring

      • lag screws

        • screws perpendicular to fracture plane  

           

POSTERIOR MALLEOLAR FRACTURE

• Nonoperative

  • indications

    • < 25% of articular surface involved

      • size should be calculated on CT since plain radiographs are unreliable

    • < 2 mm articular stepoff

    • stable syndesmosis 

• Operative 

  • ORIF

    • indications

      • > 25% of articular surface

      • > 2 mm articular stepoff

      • syndesmotic instability

      • posterior subluxation of talus

    • technique

      • approach

        • posterolateral approach 

            

          • interval between FHL and peroneal tendons

          • common approach since posterior malleolus fractures are frequently posterolateral

        • posteromedial approach

        • percutaneous 

        • decision of approach will depend on location of fracture, degree of displacement, and need for fibular fixation

      • fixation methods

        • antiglide plate

        • percutaneous A to P lag screws 

          • fix fibula first 

          • must be well reduced

      • syndesmosis injury 

         

        • stiffness of syndesmosis restored to 70% normal with isolated fixation of posterior malleolus vs 40% with isolated syndesmosis fixation 

           

          • PITFL may remain attached to posterior malleolus and syndesmotic stability may be restored with isolated posterior malleolar fixation 

             

        • stress examination of syndesmosis still required after posterior malleolar fixation

      • 40-90% of distal third spiral tibia fractures have an associated posterior malleolus fracture

BOSWORTH FRACTURE-DISLOCATION

• Overview

  • rare fracture-dislocation of ankle where fibula is entrapped behind tibia and is irreducible

  • posterolateral ridge of the distal tibia hinders reduction of the fibula 

     

  • open reduction of fibula and internal fixation is required

HYPERPLANTARFLEXION VARIANT

• Overview

  • fracture-dislocation of the ankle due to hyperplantarflexion 

     

  • main feature is a vertical shear fracture of the posteromedial tibial rim

  • "spur sign" is pathognomonic 

    • double cortical density at the inferomedial tibial metaphysis

    • 79% sensitive, 100% specific 

  • ORIF of posterior malleolus with antiglide plating

OPEN ANKLE FRACTURE

• Operative

  • emergent operative debridement and ORIF

    • indicated if soft tissue amendable 

    • primary closure at index procedure can be performed in appropriately-selected grade I, II, and IIIA open fractures in otherwise healthy patients without gross contamination 

       

  • external fixation 

     

    • indications

      • significant soft tissue compromise 

      • unstable fracture in splint/cast

ASSOCIATED SYNDESMOTIC INJURY

• Overview

  • 10% of all ankle fractures 

    • higher incidence with higher fibula fractures 

      • Weber A fracture <10%

      • Weber B fractures ~40-50%

      • Weber C fracture patterns (>80%) 

         

    • fixation usually not required when fibula fracture within 4.5 cm of plafond

• Evaluation 

   

  • static views

    • tibiofibular clear space

      • measure tibiofibular clear space 1 cm above joint 

    • tibiofibular overlap

    • medial clear space 

  • dynamic views

    • manual external-rotation stress

      • abduction/external rotation stress of dorsiflexed foot 

         

      • lateral stress radiograph has greater interobserver reliability than an AP/mortise stress film

        • instability of the syndesmosis is greatest in the anterior-posterior direction 

           

    • gravity-stress

      • patient placed in lateral decubitus position

      • similar effectiveness to manual ER stress test

    • Cotton/hook test

      • intraoperative assessment 

      • bone hook around fibula used to pull while placing counter traction on tibia 

• Treatment

  • syndesmotic screw or suture fixation

    • indications

      • widening of medial clear space 

         

      • tibiofibular clear space (AP) greater than 5 mm 

      • tibiofibular overlap (mortise) narrowed

    • technique 

      • length and rotation of fibula must be accurately restored 

         

        • "Dime sign"/Shentons line to determine length of fibula 

      • fixing lateral and/or posterior malleolus first my obviate need for syndesmotic fixation  

         

      • outcomes are strongly correlated with anatomic reduction 

         

        • placing reduction clamp on middle medial tibial ridge and the lateral fibular ridge at the level of the syndesmosis (1-2 cm proximal to mortise) will achieve reliable anatomic reduction 

           

        • maximum dorsiflexion not required during screw placement (over-tightening) 

        • open reduction required if closed reduction unsuccessful or questionable

        • Improved reduction with direct visualization of the syndesmosis at the level of the joint  

      • one or two cortical screw(s) or suture-button devices 2-4 cm above joint

        • angled posterior to anterior 20-30 degrees (fibula posterior to tibia)

      • controversies

        • number of screws

          • 1 or 2 most commonly reported

        • number of cortices

          • 3 or 4 most commonly reported

        • size of screws

          • 3.5 mm or 4.5 mm screws

        • implant 

          • suture button has lower rate of malreduction and reoperation rate than screws 

             

      • hardware removal with screws

        • no difference in outcomes seen with hardware maintenance (breakage or loosening) or removal at 1 year

        • outcome may be worse with maintenance of intact screws 

           

    • postoperative

      • screws should be maintained in place for at least 8-12 weeks

      • must remain non-weight bearing, as screws are not biomechanically strong enough to withstand forces of ambulation

      • any postoperative malalignement or widening should be treated with open debridement, reduction, and fixation 

         

DIABETIC ANKLE FRACTURES (WITH OR WITHOUT NEUROPATHY)

• Pathophysiology 

  • poor circulation impairs wound and fracture healing

  • loss of protective sensation

  • poor bone quality

• Nonoperative treatment

  • Stable unimalleolar ankle fractures

  • Poor outcomes and increased risk for:

    • loss of reduction (greatest risk) 

       

    • Charcot arthropathy

    • malunion

    • nonunion 

• Operative treatment

  • Risks

    • prolonged healing

    • high risk of hardware failure

    • high risk of infection

    • lower functional outcomes

    • need for future amputation 

  • Enhanced fixation 

     

    • multiple quadricortical syndesmotic screws (even in the absence of syndesmotic injury)

    • tibiotalar Steinmann pins or hindfoot nailing

    • ankle spanning external fixation

    • augment with intramedullary fibula K-wires

    • stiffer, more rigid fibular plates (instead of 1/3 tubular plates)

      • compression plates

      • small fragment locking plates

    • recent evidence supports acute or subacute tibiotalocalcaneal fusion in these patients  

       

  • Delay weightbearing 

    • maintain non-weightbearing postop for 8-12 weeks (instead of 4-8 weeks in normal patients)

COMPLICATIONS

• Nonoperative

  • ulceration from cast

  • delayed union or nonunion

  • malunion

  • post-traumatic arthritis

  • DVT (5%)

  • ankle stiffness

• Operative 

  • wound problems (~5%) 

     

  • deep infections (1-2%)

    • up to 20% in diabetic patients

      • largest risk factor for diabetic patients is presence of peripheral neuropathy 

         

  • malunion

    • articular impaction of tibial plafond in SAD injuries should be addressed at time of surgery 

       

    • corrective osteotomy requires obtaining anatomic fibular length and mortise correction for optimal outcomes 

       

  • post-operative stiffness

    • Loss of dorsiflexion with posterior fixation 

       

  • post-traumatic arthritis

    • rare with anatomic reduction and fixation 

       

    • very common in "log-splitter" type injuries (trans-syndesmotic fracture-dislocations in which the talus is driven into the distal tibiofibular articulation) 

       

  • neurologic injury 

    • superficial peroneal nerve injury (10-15%) 

       

      • At risk with lateral approach to distal fibula, posterolateral, and anterior/anterolateral approaches 

      • Two terminal nerve branches that innervate dorsum of the foot 

  • hardware irritation 

    • hardware removal ~20%

    • risk factors 

      • younger age

      • women

      • longer operative time

    • peroneal tendonitis (5-40%) 

       

      • posterolateral plating of fibula

      • risk factors

        • distal placement of fibula plate 

        • protruding screw head in most distal hole of fibula plate

    • posterior tibial tendonitis

      • at risk with posterior medial malleolus screw placement 

  • complex regional pain syndrome

PROGNOSIS

• Excellent for stable ankle fractures treated nonoperatively

• Outcomes following operative treatment generally very favorable

  • 90% mild/no ankle pain with minimal limitations and near full functional recovery at 1 yr 

    • Positive predictors for good outcomes

      • age <40

      • male

      • ASA 1 or 2

      • absence of diabetes

  • Risk factors for adverse outcomes 

    • older age

    • osteoporosis

    • diabetes

    • peripheral vascular disease

    • female

    • higher ASA 

    • smoking

    • alcohol use

    • lower level of education