The Ankle and Foot Flashcards
What type of joint is the ankle?
Hinge-type
What are the ligaments of the ankle?
Lateral ligament - anterior talofibular, posterior talofibular, calcaenofibular
Medial ligament (deltoid): tibionavicular, tibiocalcaneal, anterior and posterior tibiotalar
Which muscles are responsible for dorsiflexion of the foot (4) and what are these innervated by?
TA
EDL
EHL
FT (slightly)
Innervated by deep fibular/peroneal nerve
Which muscles are responsible for plantarflexion (6) of the foot and what are these innervated by?
Gastrocnemius Soleus (Plantaris) FHL FDL Tibialis posterior
Innervated by tibial nerve
What are the 3 major ligaments of the foot?
Plantar calcaneonavicular
Long plantar
Plantar calcaneocuboid
What is the medial longitudinal arch of the foot composed of?
Talus, calcaneus, navicular, 3x cuneiform, 3x metatarsals
What is the lateral longitudinal arch of the foot composed of?
Calcaneus, cuboid, lateral 2 metatarsals
What is the transverse arch of the foot composed of?
Cuboid, 3x cuneiforms
Which is weaker - the lateral or the medial ligaments of the ankle?
Lateral - more prone to sprain.
Which X-ray views of the ankle would you order if you suspect an ankle injury?
- AP
- Lateral
- Mortise - ankle at 15 degrees of internal rotation, which gives true view of ankle joint and shows a symmetric joint space with no talar tilt
What are the Ottawa Ankle Rules?
Guides use of X-ray in emergency for potential ankle injuries
X-rays are only required if:
Pain in the malleolar zone AND
bony tenderness over the posterior aspect of the medial or lateral malleolus
OR
inability to weight bear both immediately after injury and in the ER
In addition to an X-ray, what other investigation would be ordered in an ankle injury to better characterize fractures?
CT
What is the Danis-Weber classification of ankle fractures based on?
Level of fibular fracture relative to syndesmosis
Describe a Danis-Weber Type A (2). What is it caused by?
Infra-syndesmotic
Caused by a pure inversion injury -
- Avulsion of lateral malleolus OR torn calcaneofibular ligament
- +/- shear fracture of medial malleolus
How is a Danis-Weber Type A fracture managed?
Most Type A #s are stable/non-displaced - minimal splintage (firm bandage or stirrup brace applied mainly for comfort)
Occasionally displaced requires ORIF + post-operative removable splintage boot for 6 weeks
Describe a Danis-Weber Type B ankle fracture. (3) What is it caused by?
Trans-syndesmotic (can be intact/partially torn)
External rotation and eversion
- Spiral fracture at lateral malleolus
- Syndesmosis can be intact/partially torn
- +/- avulsion of medial malleolus OR rupture of deltoid ligament
How is an undisplaced Danis-Weber Type B ankle fracture managed?
Undisplaced - if syndesmosis or mortise intact, below-knee cast applied with the ankle in neutral position, overboot is fitted after X-rays at 2 weeks to confirm that fracture remains undisplaced. Cast discarded after 6-8 weeks.
How is a displaced Danis-Weber Type B ankle fracture managed? (2)
Closed reduction involving traction and internal rotation of foot. If successful, cast is applied, following the same routine for undisplaced fractures (overboot fitted at 2 weeks after X-ray confirms stabilisation, cast discarded after 6-8 weeks)
Failure of closed reduction of late redisplacement - internal fixation.
Describe a Danis-Weber type C ankle fracture (3). What is it caused by?
Supra-syndesmotic.
Caused by pure external rotation injury
- Syndemosis usually torn.
- Avulsion of medial malleolus OR torn deltoid ligament
- +/- Posterior malleolus avulsion with posterior tibio-fibular ligament
What is the Maisonneuve fracture?
Spiral fracture of proximal 1/3 of fibula; most commonly occurring alongside a Type C ankle fracture.
Describe the management of Danis-Weber Type C fractures.
Both displaced and undisplaced fractures are bad and highly unstable. Therefore ORIF!
Describe three clinical features of an Achilles tendon rupture.
- Ripping/popping sensation/sound often heard and felt
- Sensation of having been kicked in heel - looking around and no one’s there
- Positive Thompson’s test
What is Thompson’s test?
Used to diagnose achilles tendon rupture.
Lying prone, or kneeling on chair - squeeze calf muscles
Normal - should cause passive plantar flexion
A positive test = nothing! No plantarfexion = rupture
Where is the most common site of Achilles tendon rupture?
About 4 cm above tendon insertion - vascular watershed or where blood supply is poorest
How is Achilles tendon rupture treated? (2)
Non-operatively: cast of foot in plantarflexion (tendon relaxed) for 8-12 weels
Operative - surgery, then cast as above
Early rehab and physiotherapy important!
What is the cause of hallux valgus? What is it associated with?
- Valgus alignment on 1st MTP causes eccentric pull of extensor and intrinsic muscles - reactive exostosis forms with thickening of skin to create bunion
- Most often associated with poor-fitting footwear but can be hereditary; 10x more frequent in women
How is halux valgus treated? (2)
- Non-operative: properly fitted shoes (low heel) and toe spacer
- Surgical: goal is to restore normal anatomy - osteotomy with realignment of 1st MTP joint or arthrodesis
What is a Jones fracture?
Fracture of the midshaft 5th MT caused by a stress injury
What is a March fracture and how is it treated?
Fracture of shaft 2nd, 3rd MT caused by a stress injury. Symptomatic
What is a Lisfranc fracture and how is it treated?
Tarso - MT fracture - dislocation caused by fall onto plantar flexed foot or direct crush injury
ORIF
List 3 complications of an Achilles tendon rupture
- Infection
- Sural nerve injury
- Re-rupture - surgical repair decreases likelihood of rerupture compared to nonoperative management
