Hindfoot Fractures

1. Hindfoot Fractures Moritz Haager July 8, 2004

2. Jeez, I sure hope I don’t bust my hindfoot..

3. What articulations comprise the ankle joint complex?

4. What articulations comprise the ankle joint complex? • Talocrural joints • Distal tibia – talus • Medial malleolus – talus • Lateral malleolus – talus • Distal tibia – distal fibula (distal tibiofibular joint) • Collectively allow dorsiflexion and plantarflexion • Subtalar joints 5. Talus – Calcaneus • Contributes to inversion and eversion • Hence the talus & calcaneus are key to ankle function 4 1 2 3 5

5. AP Radiograph • Adequacy • Fibula & tibia above talus • Open medial clear space > 10 mm

6. Lateral Radiograph • Adequacy • Malleoli superimposed • Joint space cleary visible w/o overlap • Look for signs of ankle effusion • Lucency anterior or posterior to joint capsule

7. Mortise View • Evaluates articular surface • Technique • Leg is internally rotated 15 – 20o • X-ray beam perpendicular to intermalleolar line • Adequacy • No overlap of talar dome & joint space • Med. & lat. clear spaces open • Articular surfaces should be parallel throughout i.e. uniform joint width • Should see mild (>1 mm) overlap of tibia & fibula • Medial clear space should not exceed 4 mm • Lateral clear space should not exceed 5.5 mm lateral clear space (< 5.5 mm) medial clear space >1 mm

8. Talus anatomy Talar dome or trochlea Head Body Neck • Midfoot (Chopart joint) Subtalar joint • What is the risk with talar neck fractures? Why? • Avascular necrosis • Most of the vascular supply to body via neck

9. Talar fractures • Minor talar fractures • Chip and avulsion fractures of neck ,head, and body. • Usually same mechanism as ankle sprains • Talar neck fractures • 50% of major talar injuries. • extreme dorsiflexion force (aviator’s astralagus) • Frequent associated fractures • Hawkins classification • Talar body fractures • 23% of all talar fractures (including minor fractures) • Major talar body fractures are uncommon • usually axial loading (e.g. falls) • Talar head fractures • Uncommon (5-10%) • compressive force transmitted up through the talonavicular joint applied on a plantarflexed foot

10. Hawkins Classification of Talar Neck Fractures • Type 1: = nondisplaced; • Type 2: subtalar subluxation • Type 3: dislocation of the talar body (50% open #’s) • Type 4: dislocation of the talar body & distraction of the talonavicular joint. • Fracture type influences management & prognosis

11. Calcaneal anatomy Lateral malleolus apex of posterior facet Anterior process Posterior tuberosity Sustenaculum tali

12. Axial (Harris) View Lateral malleolus Sustenaculum tali Posterior tuberosity

13. Bohlers Angle Posterior tuberosity apex of posterior facet apex of anterior process

14. Calcaneus Fractures • Classification • Compression #’s • Posterior tuberosity #’s • Anterior process #’s • Sustenaculum tali #’s • High energy mechanism  associated injuries • 20% will have vertebral fractures

16. Chip (osteochondral) fracture

20. Talus fracture

22. Type 3 talar neck fracture

23. Normal

25. Type 2 talar fracture

26. Oblique View Anterior process #

27. Posterior tubercle #

35. Key Concepts • Plain films tend to underestimate hindfoot fractures • often require CT or MRI for better evaluation • Calcaneal fractures are • frequently bilateral • associated with other injuries • Abnormal Bohlers angle may be only clue • Talus fractures are at risk for AVN

36. Questions ?