Regarding talar neck fracture of foot

1. TALUS FRACTURE

2. INTRODUCTION
• The talus acts as a link between the ankle, subtalar and transverse tarsal
joints.
• Talus fractures account for 2% of all lower extremity injuries and 5–7% of
all foot injuries.
• About 70% of the talar surface is covered by articular cartilage along its
five weight-bearing surfaces and hence almost any talar fracture involves
a joint.

3. • It is devoid of muscle or tendon attachments and its vascular supply is
dependent entirely on fascial structures.
• As a result, capsular disruptions can result in osteonecrosis.
• Fractures are classified according to the anatomic location as
 lateral process fractures
 posterior process fractures
 talar head fractures
 talar body fractures
 talar neck fractures.

4. TALAR NECK FRACTURES

5. • Talar neck fractures occur commonly with forced dorsiflexion and were
historically known as the ‘aviator’s astragalus’ as it was common when
planes impacted the ground and the rudder bar forcefully dorsiflexed the
foot resulting in a talar neck fracture

6. MECHANISM OF INJURY
• The talar neck fractures by forced impaction on the anterior margin of the
tibia during hyperdorsiflexion.
• This is most commonly seen with motor vehicle accidents or a fall from a
height

7. CLINICAL EVALUATION
• Patients present with swelling of the ankle with tenderness of the talus
and subtalar joint and painful foot movements.
• About 15–25% of fractures are open and due to high-energy
mechanism injuries.
• Prolonged dislocation with tenting of the skin may result in pressure
necrosis on the overlying soft tissues, compromising soft-tissue
integrity and resulting in possible infection.
• Emergency reduction of the talus under sedation prior to sending the
patient for radiographs is recommended.
• Foot compartment syndrome is rare but possible and must be carefully

8. RADIOLOGICAL EVALUATION
• In addition to the standard anteroposterior (AP) and lateral radiographs
of the ankle, a Canale view is obtained.
• This provides an optimum
view of the talar neck.

9. • CT is helpful to delineate the fracture morphology and assess articular
involvement.
• Fractures that appear non-displaced on plain radiographs may show
unrecognized comminution or articular step-off on CT scan.

10. CLASSIFICATION
• The original classification of talar neck fractures by Hawkins had three
types of fractures, and Canale and Kelley added a fourth type

11. • Types II, III and IV are associated with progressive severity in
disruption of vascular supply to the fracture fragments.
• In type I fractures, the incidence of osteonecrosis is 0–15%,
in type II it is 20–50%
in type III it is 20–100% and
in type IV it is usually 100%

13. TREATMENT
• The management depends on the degree of displacement.
• Type I fractures can be treated with a short leg cast for 8–12 weeks.
• The patient should remain non-weight bearing for 6 weeks until clinical
and radiographic evidence of fracture healing is present.
• Many surgeons however prefer surgical treatment to avoid the risk of
late displacement.
• This fracture pattern is amenable to percutaneous internal fixation with
‘lag screws’ from a posterolateral insertion site.

14. • Displacement greater than 2 mm requires surgical management to
avoid further vascular and soft-tissue compromise.
• Immediate closed reduction is indicated, with emergency open reduction
and internal fixation (ORIF) for all open or irreducible fractures,
particularly those with residual subluxation, dislocation or pressurized
soft tissues.
• If open reduction is necessary, all major fragments should be salvaged.
• Primary arthrodesis is usually avoided.
• Surgical approaches include the anteromedial, posterolateral,
anterolateral and the combined anteromedial– anterolateral.
• The combined approach is used only when greater visualization of the

15. • Internal fixation is usually accomplished with two interfragmentary lag
screws or headless screws placed perpendicular to the fracture line.
• The screws can be inserted in antegrade or retrograde fashion.
• Posterior-to-anterior directed screws have been demonstrated to be
biomechanically stronger.
• Medial comminution may require bone grafting and medial plating to
prevent subsequent varus malunion.
• Titanium screws may offer an advantage if postoperative MRI is to be
considered for evaluation of postoperative osteonecrosis.
• A short leg cast or removable boot should be placed postoperatively
for 8–12 weeks, and the patient should be kept non-weight bearing

17. • The Hawkins sign represents osteopenia that is seen beneath the
subchondral surface of the talar dome and is seen at 6–8 weeks after the
fracture, indicating talar revascularization.
• Absence of this sign in radiographs performed at 6 weeks indicates
possible avascular necrosis.
• If osteonecrosis is suspected, MRI may be useful in making an early
diagnosis.
• If the fracture has healed and no cystic changes or collapse are noted,
progressive, protected weight bearing can be instituted at 8 weeks, with
regular clinical and radiographic re-evaluation

18. COMPLICATIONS
• Post-traumatic arthritis occurs in 40–90% of cases and is due to
chondral injury at the time of fracture or persistent articular incongruity.
•
• This may occur in either the ankle or subtalar joints.
• The rates of arthritis in the subtalar joint, ankle joint or both the joints are
50%, 30% and 25%, respectively.

19. • Osteonecrosis is common and is related to initial fracture
displacement as mentioned above.
• Delayed union (>6 months) may occur in up to 15% of cases.
• It may be treated by open reduction and bone grafting.

20. TALAR HEAD FRACTURES

21. • Fractures of the head of the talus constitute 5–10% of talar injuries.
• Two mechanisms of injury have been suggested:
 axially directed loading and compression of the talar head
 a dorsal compression fracture on the anterior tibial plafond.
• Plain radiographs may define the fracture clearly,
• But a CT scan is often necessary for definitive diagnosis and evaluation
of displacement.

22. • The fracture of the head with loss of support of the talonavicular joint
may be associated with clinical instability of the triple joint complex.
• Injuries to the calcaneocuboid and subtalar joints are common with this
injury
• Displaced fractures of the head of the talus should be treated with open
reduction and internal fixation with cancellous lag screws using an
anteromedial approach.
• Care should be taken to not strip any remaining vascular supply of the
head.

23. • Early motion can be started from approximately 2 weeks after surgery
and delayed weight bearing is initiated at a minimum of 6 weeks.
• Osteonecrosis of the fractured segment of the head has been reported to
be 10%, and, if degenerative arthrosis occurs, talonavicular arthrodesis
may be indicated

24. LATERAL PROCESS FRACTURES

25. • Lateral process fractures, also described as snowboarder fractures,
are created by forced dorsiflexion and external rotation of the foot.
• This fracture is commonly missed on initial presentation on plain
radiographs of the ankle.
• CT is helpful to ascertain the extent of the fracture, which may
encompass a significant portion of the lateral aspect of the posterior
facet.

26. • Fractures with less than 2 mm displacement are treated nonoperatively
in a short leg cast for 6 weeks, followed by 6 weeks in a removable
weight-bearing cast.
• Fractures with more than 3–4 mm displacement or involving >10% of
the articular surface should be fixed using lag screws

27. POSTERIOR PROCESS
FRACTURES

28. • Fractures of the posterior process involve the posterior 25% of the
articular surface and include the posteromedial and posterolateral
tubercles.
• They occur during forced ankle inversion whereby the posterior
talofibular ligament avulses the lateral tubercle or by forced equinus and
direct compression.
• The posterolateral tubercle is more frequently involved, and flexion and
extension of the hallux may exacerbate symptoms because of the close
proximity of the flexor hallucis longus tendon in its posterior groove

29. • Diagnosis of fractures of the posterior process of the talus can be
difficult, and should be suspected when a patient previously diagnosed
to have an ankle sprain does not improve by 6 weeks.
• Non-displaced or minimally displaced fractures without significant
subtalar involvement are treated with a short leg cast for 6 weeks
whereas displaced fractures are treated operatively.
• If the fragment is large with significant subtalar joint involvement, it
should be fixed.
• If the fragment is small or diagnosed late, primary excision is performed.

30. TALAR BODY FRACTURES

31. • It is important to distinguish talar body fractures from talar neck
fractures.
• Inokuchi et al. identified these injuries as talar body fractures if the
inferior fracture line was proximal to the lateral process of the talus and
as talar neck fractures if the inferior fracture line was distal to the lateral
process of the talus.
• Although the incidence of osteonecrosis is similar between talar neck
and talar body fractures, a higher incidence of post-traumatic subtalar
osteoarthrosis has been noted after talar body fractures.

32. • Non-displaced talar body fractures have a reported incidence of
osteonecrosis of 25%; however, with displacement, the rate increases to
50%.
• Diagnosis should be made by a plain radiograph, and CT may be
indicated for complete evaluation of the fracture pattern and
displacement.
• Displaced fractures should be treated with ORIF.
• An 88% incidence of osteonecrosis or post-traumatic arthritis has been
reported, with worse results occurring in comminuted and open fractures

33. • Comminuted fractures of the body of the talus with gross displacement
are difficult to treat with uniformly poor longterm results.
• Accurate replacement of the fragments is often impossible and
procedures such as talectomy or calcaneotibial fusion are required.
• As the results of talectomy are usually poor, calcaneotibial fusion
combined with talectomy is preferred.
• The foot is painless and stable, and enough compensatory movement
usually develops in the midtarsal joints to enable the patient to walk
with a fairly elastic gait.

34. SUBTALAR DISLOCATION
(PERITALAR DISLOCATION)
• Subtalar dislocation refers to the simultaneous dislocation of the distal
articulations of the talus at the talocalcaneal and talonavicular joints.
• The dislocations are closed in approximately 75% of patients.
• Most (85%) of the dislocations are medial (the foot is dislocated medial
to the talus), although lateral, anterior and posterior dislocations have
been reported.
• Forced inversion of the foot results in a medial subtalar dislocation,
whereas eversion produces a lateral subtalar dislocation.

35. • All subtalar dislocations require closed reduction.
• Under adequate analgesia with knee flexion and longitudinal foot
traction, the foot deformity is accentuated to ‘unlock’ the calcaneus.
• The deformity is then reversed and reduction occurs with a ‘clunk’.
• Post-reduction CT should be performed to fully ascertain the extent of
associated osteochondral injuries and congruency of reduction of the
subtalar joint.
• Intraarticular fragments blocking congruent reduction require surgical
excision.

36. • Irreducible dislocations occur in 32% of patients owing to entrapment of
bone or soft-tissue structures.
• With medial dislocations, the talar head can become trapped by the
capsule of the talonavicular joint, the extensor retinaculum or extensor
tendons, or the extensor digitorum brevis muscle.
• With a lateral dislocation, the posterior tibial tendon may be entrapped.
• Open reduction is required in such instances and is usually performed
through a longitudinal anteromedial incision for medial dislocations and a
sustentaculum
• tali approach for lateral dislocations

37. THANK YOU