LL Ultrasound and Cases

Question 1

Someone has slipped whilst fell-running and has a deformed and painful right ankle

What is the diagnosis?

Answer 1

dislocation of the ankle

Question 2

In a dislocated ankle, how would you assess the vascular status (perfusion) of the foot?

Which arteries should be palpated and which is easiest to palpate?

Answer 2

try to palpate pulses

try to palpate posterior tibial artery and dorsalis pedis

DP is easier to palpate as it is superficial and easy to compress against the bones of the foot

PT is harder to palpate as it is close to the tendons behind the medial malleolus

Question 3

Why can it be difficult to palpate pulses after dislocation of the ankle?

Answer 3

the normal bony landmarks are now deformed or lost

especially the medial malleolus - the landmark for posterior tibial artery

Question 4

where is the dorsalis pedis pulse palpated?

Answer 4

lateral to the extensor hallucis longus tendon on the dorsal surface of the foot

Question 5

If distal pulses are not palpable, how else could you assess perfusion?

Answer 5

looking at warmth, colour and capillary refill time

Question 6

In general, how would you assess the neurological status of the foot after ankle dislocation?

Answer 6

you examine the regions of the skin of the foot innervated by major peripheral nerves

compare this to the other foot

Question 7

Why would you examine the sole of the foot when assessing neurological status?

Answer 7

this assesses the function of:

1. medial and lateral plantar nerves
2. saphenous nerve
3. tibial nerve
4. sural nerve

Question 8

Which nerve supply these areas of the sole of the foot?

Answer 8

Question 9

Which nerves supply the skin of the foot?

Answer 9

Question 10

How might a patient experience compromise of nerves?

Answer 10

numbness or reduced sensation

or an abnormal sensation and tingling

Question 11

How can this fracture be described?

Answer 11

comminuted intra-articular tibial plateau fracture

the distal portion of the fragment (tibial shaft) is anteriorly displaced

Question 12

What feature is visible in this X-ray?

Answer 12

lipohaemarthrosis

Question 13

What is meant by a comminuted fracture?

Answer 13

a break or splinter of the bone into more than two fragments

Question 14

What is acute compartment sydrome?

Answer 14

increased pressure inside a muscle compartment that most often happens in response to trauma

the fascia does not expand to accomodate swelling (oedema, bleeding, etc.)

the pressure increases inside the compartment and causes pain

Question 15

What can acute compartment syndrome lead to if it is not treated?

How is it treated?

Answer 15

it can lead to vascular occlusion, nerve compression and muscle necrosis

it is a surgical emergence and requires immediate fasciotomy

Question 16

What is the likely diagnosis when:

a patient has a swollen, warm and tender leg but their thigh looks normal

Answer 16

deep vein thrombosis

if a patient has had a fracture, their leg is immobile

if they are not eating or drinking much, they may be dehydrated

Question 17

Should a fracture patient with a suspected DVT be anticoagulated?

Answer 17

YES

Unless the patient has a contraindication to being anticoagulated

Question 18

If the thigh is not swollen in a DVT, which vessel is most likely to be affected?

Answer 18

popliteal vein

if the thigh is not swollen, it is unlikely to be more proximal than this

Question 19

How should a patient with a suspected DVT be managed initially?

Answer 19

by calculating the Wells score and anticoagulating as per DVT treatment guidelines

(treatment dose - not prophylactic dose)

Question 20

What questions should be asked when a patient has a suspected DVT?

Answer 20

1. chest pain - check sats, resp rate

if there are any chest symptoms, need to consider PE

2. tell the patient to inform staff if they experience any chest symptoms (pain, tightness, breathlessness)

Question 21

What is the diagnosis?

What structures may be damaged by this injury?

Answer 21

posterior dislocation of right hip

potential injury to the acetabulum, joint capsule, hip ligaments and sciatic nerve

Question 22

What nerve could be damaged in a posterior dislocation of the hip?

Answer 22

the sciatic nerve

i.e. tibial and common fibular nerves

Question 23

How would you assess the motor function of the sciatic nerve?

Which muscle groups and associated movements would need to be examined?

Answer 23

Question 24

In general, how would you assess the sensory function of the sciatic nerve?

Answer 24

test sensation in regions of the skin innervated by the tibial and common fibular nerves

compare this to the opposite leg

Question 25

which areas of the skin are innervated by the tibial and common fibular nerves?

Answer 25

sural nerve (from tib and common fib):

• posterior and lateral leg
• lateral foot

tibial nerve:

• sole of foot - medial and lateral plantar nerves

superficial fibular nerve:

• most of dorsum

deep fibular nerve:

• web space between 1st and 2nd toes