Trauma - Foot and Ankle (Complete) Flashcards
What are the ligaments of the distal tibiofibular joint?
- Anterior inferior tibiofibular ligament
- Posterior inferior tibiofibular ligament
- Transverse tibiofibular ligament
- Interosseus ligament
What are the lateral collateral ligaments of the ankle?
- Anterior talofibular ligament
- Posterior talofibular ligament
- Calcaneofibular ligament
What are the medial collateral ligaments of the ankle?
[J Bone Joint Surg Am. 2014;96:e62(1-10)]
- Superficial layer of the deltoid ligament
- Tibionavicular ligament
- Tibiospring ligament
- Tibiocalcaneal ligament
- Superficial posterior tibiotalar ligament
2. Deep layer of the deltoid ligament - Deep anterior tibiotalar ligament
- Deep posterior tibiotalar ligament
What are normal radiographic measurements at the ankle? (measurements 1cm proximal to plafond)
- AP view:
- Medial clear space = <4mm
- Equal to the superior clear space
- Tibiofibular clear space = <6mm
- Tibiofibular overlap = 6mm or greater
- Oblique/mortise view
- Tibiofibular clear space = <6mm
- Tibiofibular overlap = 1mm or greater
- Talocrural angle = 83°+/- 4°
- Or within 5°of the contralateral side
- Angle between a line drawn perpendicular to the distal tibia articular surface and a line connecting the tips of the medial and lateral malleoli
What is the Lauge-Hansen Classification for ankle fractures?
Describes the position of the foot and the motion of the foot/talus with respect to the leg
- Supination adduction
- Weber equivalent = A
- Medial malleolus # = vertical
- Lateral malleolus # = transverse
- **Note: associated with marginal tibial plafond impaction
2. Supination external rotation - Weber equivalent = B
- Medial malleolus # = transverse
- Lateral malleolus # = short oblique starting at level of syndesmosis
- Pronation abduction
- Weber equivalent = C
- Medial malleolus # = transverse
- Lateral malleolus # = transverse comminuted fracture above the level of the syndesmosis
- Pronation external rotation
- Weber equivalent = C
- Medial malleolus # = transverse
- Lateral malleolus # = short oblique or spiral fracture above the level of the syndesmosis
What are indications for surgery in ankle fractures?
[Miller’s, 6th ed.]
- Displaced bimalleolar and trimalleolar fractures
- Displaced lateral malleolar fractures with incompetent deltoid ligament (bimalleolar equivalent)
- Displaced medial malleolar fractures
- Syndesmosis disruption
- Posterior malleolar fractures >25%
How can you assess fibular length intra-operatively?
- Compare to contralateral side
- Symmetry between the lateral talus and the medial fibula
- Restoration of Shenton line at the ankle
* Subchondral bone contour of the tibial plafond and fibula which should be smooth and unbroken - The “ball” or “dime sign”
* Described on the AP view as an unbroken curve connecting the recess in the distal tip of the fibula and the lateral process of the talus when the fibula is out to length - Normal talocrural angle
* Shortened fibula will have an increased talocrural angle
What are the eponymous ankle fracture fragments?
- Chaput
* AITFL avulses the anterolateral distal tibia - Volkmann
* PITFL avulses the posterolateral distal tibia - Wagstaffe
* AITFL avulses the anterior distal fibula
What is a ‘Bosworth fracture-dislocation” of the ankle?
Fracture of the distal fibula with an associated fixed posterior dislocation of the proximal fibula fragment which becomes entrapped behind the posterior tibial tubercle
What are the indications to fix posterior malleolus fractures?
[AAOS comprehensive review 2, 2014]
- Fracture >25% of the articular surface
- Persistent posterior talus subluxation following fixation of the fibula fracture
* Posterior malleolus fracture is often reduced via ligamentotaxis via the PITFL - Syndesmosis instability with associated posterior malleolus fracture
What is the classification of posterior malleolus fractures based on patterns identified on CT?
[JAAOS 2013;21:32-40]
Haraguchi
- Type I
- Posterolateral oblique-type wedge fragment
- Most common
- Type II
- Fracture extends from the fibular notch to the medial malleolus
- May be one or two fragments
- “Double contour sign” evident proximal to the medial malleolus when there is posteromedial extension
- Fracture extends from the fibular notch to the medial malleolus
- Type III
- Shell-shaped avulsion at the posterior lip of the tibial plafond
What are techniques for fixation of lateral malleolus fractures?
[Rockwood and Green 8th ed. 2015]
- Lag screw and neutralization plate
* Typically 3.5mm lag screw from AP or PA with a lateral 1/3 tubular plate with 3 bicortical screws proximal and 3 unicortical cancellous screws distal to the fracture - Posterior antiglide plating
- Locking plate
- Intramedullary nail
- Bridge plating for comminution
What are the advantages and disadvantages of a posterior antiglide plate vs. a lateral neutralization plate when fixing a distal fibula fracture?
[Wheeless]
Advantages
- Biomechanically stronger
- Distal screws obtain bicortical purchase
- Distal screws avoid joint
- Plate is less prominent, less hardware irritation
- Posterior incision allows access to posterior malleolar fragment
Disadvantages
- Peroneal tendon irritation
What are techniques for fixation of medial malleolus fractures?
[Rockwood and Green 8th ed. 2015]
- Two 4.0 partially threaded cancellous screws inserted unicortically parallel to each other and perpendicular to the fracture (consider washers)
- Tension band wiring
- Minifrag T-plate contoured for small fragments
- Medial buttress plate for vertical fractures
What are techniques for fixation of posterior malleolar fractures?
[JAAOS 2013;21:32-40]
- Percutaneous
* AP lag screw after indirect reduction of posterior malleolar fracture through anatomic reduction of fibular fracture - Open
- Posterolateral approach using FHL and peroneal interval
- PA lag screw
- 4.0 partially threaded cancellous screw
- Posterior buttress plate
- Small frag T-plate
What are the advantages of fixing the posterior malleolus vs. the fibula first?
- Posterior malleolus 1st = better evaluation of reduction on fluoro
* Fibular plate does not obscure - Fibula 1st = restores length aiding in reduction of the posterior malleolus
What are techniques for fixation of syndesmosis disruption?
[Rockwood and Green 8th ed. 2015]
- Position screws
- Suture/wire construct (ie tightrope)
What are techniques to augment fixation in osteoporotic bone when managing ankle fractures?
[JAAOS 2008;16:159-170] [Johal]
- Syndesmosis screws
- Locking plates
- Double stacking 1/3 semitubular plates
- Cement augmentation/Calcium phosphate cement
- Medial malleolar fixation with engagement of the far cortex with a cortical screw
- Longer plates
- TTC Steinman pin
- Supplementary K wires in plated fibulas
What is the normal motion of the fibula during ankle ROM (rotation, translation, migration)?
[J Bone Joint Surg Am. 2014;96:603-13]
- With ankle plantar flexion, fibula:
- Migrates distally
- Translates anteromedially
- Internally rotates
- With ankle dorsiflexion, fibula:
- Migrates proximally
- Translates posterolaterally
- Externally rotates
What ligaments contribute most to syndesmosis stability?
[J Bone Joint Surg Am. 2014;96:603-13]
- AITFL (35%)
- PITFL
- Deep PITFL (33%)
- Superficial PITFL (9%)
- ***Therefore, PITFL = 42% and contributes most to stability
- Interosseous ligament (22%)
What are the typical fracture patterns associated with syndesmosis injuries?
[J Bone Joint Surg Am. 2014;96:603-13]
- Pronation external rotation (Weber C)
- Supination external rotation (Weber B)
- Maissonneuve fracture
What is the most reliable radiographic finding in the detection of syndesmotic injuries?
[J Bone Joint Surg Am. 2014;96:603-13]
Tibiofibular clear space
- It is not affected by leg position
What is the most common mechanism of syndesmotic injury?
[J Bone Joint Surg Am. 2014;96:603-13]
External rotation and hyperdorsiflexion
What are techniques for intraoperative assessment of syndesmosis stability?
- Cotton test
- Direct translation of the fibula via a clamp or hook
- Lateral directed force
- Positive if lateral translation >2mm
- External rotation stress test
* Positive if medial clear space widens - Ankle arthroscopy
* Direct visualization of the AITFL and PITFL - Compare to opposite side
What are keys to avoid syndesmois malreduction?
[J Am Acad Orthop Surg 2015;23:510-518]
- Anatomic reduction of fibula fracture (length, alignment, rotation)
- Clamp should be placed at the level of the syndesmosis
* From the lateral malleolar ridge to the centre of the AP width of the tibia - Avoid overcompression with the clamp
- Directly visualize reduction
- Compare to opposite side via fluoro
What are the options for surgical stabilization of the syndesmosis?
- Syndesmotic screws
- Suture button
- Posterior malleolar fracture fixation
What is the rate of syndesmosis malreduction after syndesmosis screw based on postop CT?
52% are malreduced
In the presence of a posterior malleolar fracture with syndesmosis instability, why should you fix the posterior malleolar fracture rather than syndesmosis screws?
[JAAOS 2013;21:32-40]
Fixation of posterior malleolar fractures results in:
- More anatomic reduction of the syndesmosis (vs. syndesmosis screws)
- Rstores the length of the PITFL
- Adds greater stability/stiffness (vs. syndesmosis screw)
- Restores 70% vs. 40% stiffness
- Prevents posterior translation of the fibula
What are the 3 typical tibia fragments following a pilon fracture due to intact ligaments?
- Medial (deltoid ligament)
- Posterolateral = Volkman (PITFL)
- Anterolateral = Chaput (AITFL)
Based on a CT scan study what are the 6 major articular fragments in a pilon fracture (Topliss et al)?
[JAAOS 2011;19:612-622]
- Anterior
- Posterior
- Anterolateral
- Posterolateral
- Medial
- Die-punch
What are patient factors associated with increased risk of soft-tissue complications in pilon fractures?
[JAAOS 2011;19:612-622]
- Malnutrition
- Alcoholism
- Diabetes
- Neuropathy
- PVD
- Tobacco use
What are the pilon fracture patterns that are more common in older patients vs. younger patients?
[JAAOS 2011;19:612-622]
Older patients
- Coronal fractures
- Low energy injuries
- Valgus angulation
Younger patients
- Sagittal fractures
- High energy injuries
- Varus angulation
What does the assessment of soft tissue envelope include in a pilon fracture?
[JAAOS 2011;19:612-622]
- Open/closed
- Fracture blisters
- Edema
- Ecchymosis
What imaging is required for assessment of pilon fractures?
[JAAOS 2011;19:612-622]
- Radiographs
- AP, lateral, mortise ankle views
- Full length AP and lateral tibia/fibula views
- CT
- After initial ex-fix improves fracture fragment visualization secondary to ligamentotaxis
- Reasons to get CT include:
- Evaluate extent of articular involvement
- Determine surgical approach
- Determine need for bone graft
- Selection of implants
What are the goals of surgical management of pilon fractures?
[JAAOS 2011;19:612-622]
- Ruedi and Allgower 4 principles (1969)
- Restore the length of the fibula
- Anatomic reconstruction of the tibial articular surface
- Bone graft gaps left by impaction and comminution
- Stable internal fixation with a medial tibial plate (buttress)
- JAAOS 2011
- Reconstruction of the articular surface
- Restoration of the mechanical axis
- Stable fixation to allow early ROM
- Correct valgus deformity of the distal tibia
- Petrisor grand rounds – general fixation strategy
- Begin with posterolateral fragment
- Constant fragment
- Fix posteromedial to posterolateral fragment
- Reduce central impaction
- Reduce anterolateral fragment
- Provisional wire fixation
- Lag screw fixation
- Fix articular block to diaphysis
With respect to timing, when is definitive ORIF of pilon fractures indicated?
[JAAOS 2011;19:612-622]
Resolution of soft tissue injury determined clinically by:
- Resolution of ecchymosis over surgical site
- Re-epithelization of fracture blisters
- Healing of open fracture wounds without infection
- Resolution of soft tissue edema sufficient to allow skin wrinkle (‘wrinkle test’)
***Takes 10 days – 3 weeks
Why should fibula fixation be delayed rather than fixed at time of ex-fix of a pilon fracture?
[JAAOS 2011;19:612-622]
- Nonanatomic reduction of fibula impedes tibia reduction
- Higher fibular wound complication
- Limits incision choices at time of definitive surgery
What determines the surgical approach used for ORIF of a pilon fracture?
[JAAOS 2011;19:612-622]
Soft-tissue injury and fracture pattern
What locked plate options are available for the distal tibia?
[JAAOS 2011;19:612-622]
- Medial
- Anterolateral
- Posterior
What is the most common fracture involving the talus?
[Rockwood and Green 8th ed. 2015]
Lateral talar process fracture (snowboarder’s fracture)
What are the types of talus fractures?
[Rockwood and Green 8th ed. 2015]
- Process fractures
- Lateral process (most common)
- Medial tubercle of posterior process
- Lateral tubercle of posterior process
- Talar neck
- Most common type
- Account for 50% of all talus fractures [Foot and Ankle Surgery 2017]
- Talar body
- Talar head
What structure inserts on the lateral talar process?
[Rockwood and Green 8th ed. 2015]
Lateral talocalcaneal ligament
***Note – the lateral talar process articulates with the fibula (dorsolaterally) and the anterior portion of the posterior facet of the calcaneus (inferomedially)
The posterior process of the talus has a medial and a lateral tubercle – what inserts on each tubercle?
[Rockwood and Green 8th ed. 2015]
- Medial tubercle – deltoid ligament
- Lateral tubercle – posterior talofibular ligament (PTFL)
What are the typical mechanisms of injury for each talus fracture type?
[Rockwood and Green 8th ed. 2015]
- Processes - often avulsion type or loading
- Talar neck - Hyperdorsiflexion
* Neck of talus impacts anterior distal tibia - Talar body - Axial compression
* Load between tibial plafond and calcaneous - Talar head - Axial load along longitudinal axis of foot
* Navicular loads the head
In fracture dislocations of the talus, when the talar body dislocates from the mortise where does it come to lie?
[Rockwood and Green 8th ed. 2015]
Posteromedial
- Between the medial malleolus and the Achilles tendon
- Rotates on an intact deltoid ligament
What percentage of talus fractures are open?
[Foot and Ankle Surgery 2017]
20%
What is the blood supply of the talus?
[Rockwood and Green 8th ed. 2015]
- Branches of the 3 main arteries of the leg
- Posterior tibial artery
- Branch = Artery of the tarsal canal
- Branch = deltoid artery supplies the medial 1/3 of the body
- Anterior tibial/dorsalis pedis artery
- Branches = multiple perforate the dorsal aspect of the neck supplies the talar head
- (Perforating) Peroneal artery
- Branch = artery of the tarsal sinus
- Branch = artery to the posterior process
- ‘Anastamotic sling’ is formed inferior to the neck by the artery of the tarsal sinus and tarsal canal
- Provide perforators that flow retrograde to supply the body
What is the average talar neck angle?
[Foot and Ankle Surgery 2017]
Approx.. 24° medially (range 10-44)
What special radiographic view can be used to visualize the talar neck?
[Rockwood and Green 8th ed. 2015]
Canale and Kelly view
- Ankle max plantarflexion, foot 15° pronation, beam 75° from horizontal
- Demonstrates the medial talar neck allowing assessment of medial comminution and varus malalignment
What anatomic landmark can be used to distinguish talar neck fractures from talar body fractures?
[Rockwood and Green 8th ed. 2015]
Lateral talar process
- Fractures anterior are talar neck and fractures posterior are talar body
What is the Hawkins classification of talus fractures?
[Rockwood and Green 8th ed. 2015]
TYPE I
- Undisplaced talar neck fracture
- No joint dislocations
TYPE II
- Talar neck fracture with subluxation or dislocation of the subtalar joint (most common)
- IIA - subluxed subtalar joint (No AVN - 0%)
- IIB - dislocated subtalar joint (Higher AVN risk - 25%)
- ***IIA/B added by Vallier et al in 2000 [J Bone Joint Surg Am. 2014;96:192-7]
TYPE III
- Talar neck fracture with dislocation of the ankle mortise and subtalar joint
TYPE IV
- Talar neck fracture with subluxation or dislocation of the talonavicular joint and ankle mortise and subtalar joint
What is the incidence of each type and rate of osteonecrosis following talar neck fractures based on Hawkins classification?
[Current Reviews in Musculoskeletal Medicine (2018) 11:456–474]
Current Reviews in Musculoskeletal Medicine (2018) 11:456–474
- See Table
J Orthop Trauma 2015;29:210–215
- All dates:
- Type I - 10%
- Type II - 27%
- Type III - 53%
- Type IV - 48%
- Since 2000:
- Type I - 8%
- Type II - 21%
- Type III - 45%
- Type IV - 37%
In the context of a talar neck fracture, what is the greatest risk factor for developing post-traumatic arthritis?
[J Bone Joint Surg Am. 2014;96:192-7]
Associated talar body fracture
- 83% of patients with talar neck + body fractures developed posttraumatic OA
Other risk factors:
- Hawkins III fractures (subtalar + tibiotalar displacement)
- 56% subtalar arthritis
- 59% tibiotalar arthritis
- Concurrent calcaneus and/or plafond fractures
- 75% develop OA
***Post-traumatic OA is most common complication after talar neck fracture