Trauma symposium - dislocations

Question 1

Define:

a) Dislocation
b) Subluxation

Answer 1

a) Dislocation - complete joint disruption - bone fully out of joint space
b) Subluxation - partial dislocation - bone not fully out of joint

Question 2

Give an overview of how dislocations are diagnosed?

What else is looked for/assessed when investigating a dislocation?

Answer 2

Clinical & radiological diagnosis

Look for associated injuries (pre-op & post-op):

• ass. fractures
• neurovascular damage (eg axillary nerve in shoulder)
• soft tissue damage
• other MSK damage
• damage to other systems

Question 3

Give the common directions of dislocation - and appearance of:

shoulder dislocations

Answer 3

Anterior (90%)

Posterior (9%)

Inferior (1%)

Anterior dislocation - Squared off & locked in internal rotation

Question 4

Give the common directions of dislocation - and appearance of:

elbow dislocations

Answer 4

Posterior

Olecranon very prominent posteriorly

Question 5

Give the common directions of dislocation - and appearance of:

hip dislocations

Answer 5

Posterior

Affected leg is:

• shortened
• internally rotated
• adducted
• flexed

Anterior is rare - and confers near enough the opposite appearance

Question 6

What does this radiograph show

Answer 6

Anterior dislocation of the right shoulder

Note that in anterior dislocations it also goes quite inferior

Question 7

What causes anterior dislocations of the shoulder?

Answer 7

Abduction, extension and/or external rotation

Common in sports following falls on an outstretched hands or sudden pulling of the shoulder

Question 8

What causes posterior dislocations of the shoulder?

Answer 8

Electrocutions

Generalised tonic-clonic seizures (aka grand-mal)

Hypoglycaemic fits

Question 9

Give the common directions of dislocation - and appearance of:

knee dislocations

Answer 9

Posterior*

Loss of normal contour & extended

*lecture says anteroposteriorly but who knows what that means

Question 10

What does this radiograph show?

Answer 10

Posterior dislocation of the shoulder

‘light bulb appearance’

(the right image is normal though)

Question 11

Posterior dislocations are sometimes pretty hard to see clinically - as the shoulder looks pretty normal (as it does on a radiograph too)

What feature on shoulder examination would indicate posterior dislocation of the shoulder?

Answer 11

External rotation is a big no no

Question 12

What nerves are at risk in elbow dislocations?

Answer 12

Ulnar nerve

Radial nerve

Median nerve

Question 13

What are causes of hip dislocations?

Answer 13

Falls from height (elderly)

RTAs (yungers)

Question 14

Why is management of a dislocation of the knee different from that of other joints?

Answer 14

When knee dislocates - there is damage to both cruciates, medial and lateral ligaments - so if reduced, the bone will not stay in place

Knee dislocations are reduced and then fixed in place - before surgery to repair these ligaments is carried out

Question 15

Give the common directions of dislocation - and appearance of:

ankle dislocations

Answer 15

Lateral (most common)

Foot is externally rotated with prominent medial malleolus