Ankle Anatomy andBiomechanicsThe ankle joint consists of the talus,which articulates withthe Malleoli medially and laterally and the tibial plafondsuperiorlyIn a neutral position, approximately 90% of the load istransmitted through the tibial plafond, with the remainingload borne by the lateral talofibular articulation
Any ankle injury that results in a stable mechanicalconfiguration can potentially be treated nonsurgicallybecause biomechanically normal function is notcompromised
Restoration of normal stability and motionin patients with unstable ankle fracturesthrough open anatomic reduction andinternal fixation yields better long-termoutcomes than does closed treatment,which may not adequately reconstituteeither the anatomic constraints or themotion
ClassificationsLauge- Hansen ClassificationDanis- Weber classificationAO classification of Malleolar Fractures
Lauge- Hansen ClassificationThe initial word of the classification (eg,supination, pronation) denotes the positionof the foot at the time of injury; thefollowing phrase (eg, external rotation)denotes the direction of the deformingforce.
Supination AdductionTransverse avulsion type fracture of the distal fibulabelow the level of the joint or tear of the lateralcollateral ligamentVertical fracture of the medial malleolus.
Supination External rotation injuryDisruption of the anterior tibiofibular ligamentSpiral oblique fracture of the distal fibulaDisruption of the posterior tibiofibular ligament orfracture of the posterior malleolusFracture of the medial malleolus or rupture of thedeltid ligament
Pronation AbductionTransverse fracture of the medial malleolus orrupture of the deltoid ligamentRupture of the syndesmotic ligaments or avulsionfracture of their insertions.Short horizontal oblique fracture of the fibula abovethe level of the joint
Pronation external rotationTransverse fracture of the medial mallleolus ordisruption of the deltoid ligament.Disruption of the anterior tibiofibular ligamentShort oblique fracture of the fibula above the level ofthe jointRupture of posterior tibiofibular ligament or avulsionfracture of the posterolateral tibia.
Pronation dorsiflexionFracture of the medial malleolusFracture of the anterior margin of the tibiaSupramalleolar fracture of the fibulaTransverse fracture of the posterior tibial surface.
Danis-weber classificationBased on location and appearance of the fibularfractureType A fracture is caused by internal rotation andadduction.Type A fracture produce transverse fracture of thelateral malleolus at or below plafond.
Type B fracture is caused by the external rotation thatresult in oblique fracture of the lateral malleolus.Beginning anteromedialy extending proximally toposterolateral aspect.
Type C fractures are divided into abduction injurieswith oblique fractures of the fibula proximal to thedisrupted tibiofibular ligaments
RadiologyX ray measurements of Alignment and StabilityMeasuring the talocrural angle-4-11 degMedial clear space-should be equal to superior clearspace.(<4mm)Evaluation of syndesmosis -tibio fibular clear space should be less than 6mm onboth AP and mortice views.
TreatmentInitial evaluation-HistoryPhysical examination-Deformity,Color of the foot,PulsesCondition of the skinCarefully assessing the medial ankle over the deltoidligament for swelling and ecchymosis
Initial managementReduce the talus underneath the tibiaIf the joint is very unstable slab can be applied.The other options are spanning external fixator orcalcaneal pin traction.Rest Ice and elevationUse of continuous cryotherapy and intermittentpneumatic pedal compression pumps
Factors that affects theoutcomeMedial plafond impaction fractures with verticalmaeolus fracturesPosterior malleolar fracturesAnterolateral corner of the plafond fractures.Level and displacement of the fracture fibula.
Closed treatmentStable ankle fracturesUsually with only fibula fracturesImmobilization in cast for 4-6 weeks is the preferredtreatment.
ContraindicationsExact reduction and maintaince of the talus inmortice is not possibleShoulder fractures of the medial malleolusLarge posterior maleolar fracturesAnterolateral corner fractures.
Open treatmentStable fractures-Osteochondral fractures of the talardoneUnstable fractures.
General principlesTiming of the surgery-Type of the fracture,Skin condition,Other injuries andmedical condition.Antibiotics to reduce infections
Lateral Malleolar fracturesAvoid injuring the superficial peroneal nerveMake sure that distal fibula is fully out to lengthLaterally communited pronation abduction patternsare most difficult For maximum stability place plate posteriorly
Consider the location of the syndesmosis fixationwhen placing a fibular plate.Test the syndesmosis after lateral malleolar fixation.Beware of the short distal segments in elderlypatients with osteoporotic bone
Medial malleolar fixation4.0mm partially threaded screws work wellScrews should be perpendicular to the fracture lineand parallel for maximal compression.Spread two screws for good stabilityUse fluoroscopy to be sure screws are clear of thejoint
Deltoid ligament tearThe deltoid ligament, especially its deep branch isimportant to the stability of the ankle because itprevents lateral displacement and external rotation ofthe talusX ray will show displacement and tilting of the taluswith increased medial clear space
A 1mm lateral shift of the talus can reduce theeffective weight bearing area of the talotibialarticulation by 20% and 5mm shift can reduce by80%.It is repaired with nonabsorbable sutures.
Syndesmotic injuryIf the fibular fracture is above the level of the distaltibiofibular joint syndesmosis assumed to bedisrupted.
IndicationsSyndesmotic injuries associated with proximal fibularfractures for which fixation is not plannedSyndesmotic injuries extending more than 5 cmproximal to the plafond.
Use the syndesmosis fixation when the medial clearspace widens on intraoperative stress view after thefibula is fixedThe fibula must be accurately reduced to the tibia inall viewsUse 4.5 mm four cortex screw if the patient will bearweight postoperativelyDon’t remove syndesmotic screws 3-4 months postoperatively
Achieve perfectly symmetric tibiotalar clear spaceUse syndesmosis fixation only without fixing thefibula fracture when it is above the midfibula
Trimalleolar fracture50deg external rotation view is required for the mostaccurate assessment of the size and displacement of theposterior malleolar fragment.If the fragment of the posterior malleolus involves morethan 25 to 30% of the weigh bearing surface, it should beanatomically reduced and held with internal fixation
Irreducible fracture dislocationDeltoid ligament after being avulsed from the medialmalleolus and may be caught between malleolus and talusTrapping of the tibialis posterior tendon between medialmalleolus and talus.Bosworth fracture with entrapment of fibula behind tibia.
ComplicationsLoss of reductionMalunion-Fibula heals in short or external rotated position.Nonunion- extremely uncommonInfectionDecreased motion- Deficits in dorsiflexion is common.Ankle arthrosis-Quality of reduction