Definition
Body Fracture
- fracture line exits inferior surface behind lateral process
- into posterior facet
- intra-articular body fracture
Neck Fracture
- fracture line exits inferior surface anterior to lateral process
- in front of sinus tarsi
- extra-articular neck fracture
Types
1. Shear
2. Crush
3. Posterior Process
4. Lateral Process
5. Talus Head
1. Shear
Boyd & Knight classification
- coronal or sagittal
- horizontal
Epidemiology
13-20% of all talus fractures
Issues
Involves both AJ and posterior facet STJ
Prognosis
A. 50% develop post-traumatic arthritis
B. 25-100% AVN
- Usually patchy and so avoid collapse
Management
Undisplaced
- POP
Displaced
- ORIF
- either medial or lateral approach
- may need medial or lateral malleolar osteotomy
Nonunion
2. Crush
High energy
- associated injuries common
- prognosis as above
Management
- as above
3. Posterior Process Fractures
Anatomy
Composed of Posterolateral & Posteromedial tubercles
- separated by sulcus for FHL
- lateral larger than medial
PL tubercle
- size variable
- Superior surface non articular, attaches PTFL
- Inferior surface in continuity with posteror articular surface of Talus
PM tubercle
- also varies in size
- deep & superficial Deltoid ligaments attach
Os Trigonum
- accessory bone seen in association with PL tubercle of talus
~ 50% of feet
- may be unilateral or bilateral
- may be fused to talus or calcaneus
- relationship to PL tuberosity varies from complete separation to fusion
Mechanism
A. Forced PF
- impingement especially ballet / soccer
B. Excess DF
- increased tension on PTFL with avulsion
Examination
Tender posteriorly
Crepitus with PF
Pain with motion of Hallux in groove
DDx
Lateral process fracture
Fracture of fused os trigonum
Disruption of synchondrosis of os to talar body
Investigation
Xray
Bone Scan / CT useful in Dx
Management
Same for medial & lateral
- conservative initially
Persistent symptoms >6/12
- excision of fragement
- posteromedial or posterolateral approach
- Persistent problems from non-union not uncommon
4. Lateral Process Fractures
Eponymous name
Snowboarder's fracture
Anatomy
Wedge shaped prominence
- most lateral aspect of talar body
- point of attachment of lateral talocalcaneal, cervical, bifurcate & ATFL
- fracture involves talofibular and STJ
Mechanism
Acute dorsiflexion & inversion of foot
- most are avulsion fracture
Clinical
Identical to lateral ankle sprain
X-ray
Best seen on mortise view
Management
Depends on size and displacement
1. Large and non displaced
- non operative
2. Large and displaced
- ORIF
3. Comminuted
- non operative
- excise if problematic
5. Talus Head Fractures
Epidemiology
< 10% of all talus fractures
- rare
- often missed
Pathology
Disability via involvement articular surface
- late TNJ arthritis
- associated with subluxation / dislocation of transverse tarsal joints
Types
1. Compression fracture
- impaction injuries with force through navicular to compress head
- hyperdorsiflexion
- may also produce compression fracture of navicular
2. Shear fracture
- secondary to inversion injury
- causes midtarsal adduction with navicular tearing off portion head
Management
Non-displaced
- cast NWB
Displaced
- ORIF via medial approach
- if extremely comminuted consider TNJ arthrodesis