Ankle fracture, metatarsal stress and Lisfranc Flashcards
What rules are used for ankle fracture assessment? What do these state?
Ottawa ankle rules - minimises the unnecessary use of x-rays
These state that x-rays are only necessary if there is pain in the malleolar zone and:
- Inability to weight bear for 4 steps
- Tenderness over the distal tibia (6cm of posterior border of tibia)
- Bone tenderness over the distal fibula (6cm of its posterior border)
What systems are used to classify ankle fractures?
- Weber - most used
- Potts - describes ankle fracture in terms of malleoli involved
- AO- gives a number and letter for the location and type etc. Used for any limb fracture.
What is the Weber classification for ankle fractures?
Weber system is related to the level of the fibular fracture
- Type A = below the syndesmosis
- Type B = start at the level of the tibial plafond and may extend proximally to involve the syndesmosis
- Type C = above the syndesmosis which may itself be damaged
What is the syndesmosis?
A fibrous joint help by ligaments between the tibia and fibula
What is a Maisonneuve fracture?
Spiral fibular fracture which leads to disruption of the syndesmosis with widening of the ankle joint. Surgery is required.
What is the management of ankle fractures?
Depends on stability of the joint and patient co-morbidities. Young patients with high velocity fractures are likely to need surgery but elderly patients often fare better with conservative management as their thin bone does not hold metalwork well.
Analgesia
Non operative:
- Reduction - to remove pressure on overlying skin and subsequent necrosis
- Casting - weight bearing or not for 6 weeks
Operative:
- Surgical repair if unstable or proximal injuries - compression plate
What is a Pott’s fracture?
A bimalleolar fracture - fibula fractured above the intact distal tibiofibular syndesmosis, deltoid ligamnet ruptured and talus is subluxed laterally.
What is the tibial plafond?
Tibial distal articular surface
Name the bones of the ankle.
What is the posterior malleolus?
Posterior part of tibial plafond - shown is a posterior malleolus fracture
What are the most common mechanisms of injury of ankle farctures?
- Low-energy fall - most common
- Inversion injury to ankle
- Sporting injury
- Fall down stairs
- Fall from height
- Vehicle accident
Malleolar fractures more commonly result from rotational rather than axial force.
Avulsion fractures common.
What are the signs and symptoms of ankle fracture?
- Patients describe a ‘pop’
- Immediate pain
- Inability to weight bear
- Swelling/ecchymosis
- Deformity
- Tenderness
- Crepitus with reduced range of motion
What investigations should be done for ankle fractures?
- Plain XR - mortise view (15° internal rotation of the ankle) and a lateral x-ray should be obtained
Other:
- Stress XR - external rotation or valgus stress or standing anteroposterior. Ordered if there is suspicion of medial deltoid ligament damage to assess for lateral talar shift
- CT - if comminuted
- MRI - if need to assess articular damage and ligamentous injury
When do ankle fractures need to be immobilised for twice the normal period?
In patients with diabetes - their bones heal more slowly and there is a degree of paripheral sensory neuropathy. This prevents delayed union , skin breakdown and Charcot arthropathy.
What is the management of vertical compression fractures?
This is a severe injury usually leading to stiffness, pain and late arthritis changes.
What is Lisfranc’s ligament?
Plantar ligament which joints the base of the 2nd metatarsal to the medial cuneiform bone in the midfoot.
Which nerves wrap around the medial vs lateral malleoli?
Lateral= posteriorly the tibial nerve, anteriorly the saphenous nerve
Medial = posteriorly the sural nerve
