6: Common dislocations

Question 1

Most fractures are reduced by which means?

Answer 1

Closed reduction

skin is CLOSED e.g by manipulation

Question 2

If soft tissues are in the way of a dislocation, how are they reduced?

Answer 2

Open reduction

i.e surgically

Question 3

What can be compromised by a joint dislocation?

Answer 3

Neurovasculature

nerves, arteries, veins

Question 4

The vast majority of shoulder dislocations are (anterior / posterior).

Why?

Answer 4

anterior

bony, muscular shield posteriorly

Question 5

What is an atraumatic cause of shoulder dislocation?

In which genetic conditions can it be seen?

Answer 5

Hypermobility (i.e ligamentous laxity)

Marfan’s syndrome, Ehlers-Danlos syndrome

Question 6

Which movement can produce an anterior shoulder dislocation?

Answer 6

Extreme external rotation

Question 7

Why can falling onto the elbow produce an anterior shoulder dislocation?

Answer 7

Superior translation of shoulder causes it to dislocate anteriorly

Question 8

Which nerve may be compromised by an anterior shoulder dislocation?

Answer 8

Axillary nerve

Question 9

What is a sign of axillary nerve injury following an anterior shoulder dislocation?

Answer 9

Loss of sensation in regimental badge patch area

Question 10

What structures other than the axillary nerve may be injured by an anterior shoulder dislocation?

Answer 10

Axillary artery

Brachial plexus

Glenoid labrum

Posterior head of humerus

Rotator cuff muscles

Question 11

What are the names for lesions associated with the

a) glenoid labrum
b) posterior head of the humerus

in anterior shoulder dislocations?

Answer 11

a) Bankart lesion

b) Hill-Sachs lesion

Question 12

How are shoulder dislocations usually reduced?

Answer 12

Manually

i.e a closed fixation

Question 13

The chances of recurrent shoulder dislocation (increases / decreases) with age.

Answer 13

decreases with age

Question 14

What is the management of most shoulder dislocations?

Answer 14

Reduce

Fix (closed fixation e.g immobilisation with a sling)

Physiotherapy

Question 15

How may rotator cuff tears be treated if they are causing impingement syndrome?

Answer 15

Subacromial decompression

Rotator cuff repair

Question 16

What specific nerve injury is usually associated with axillary nerve compression in shoulder dislocations?

Answer 16

Neurapraxia

resolves within a month

Question 17

What is the nerve injury one step up from neurapraxia which may occur in shoulder dislocation and may not resolve?

Answer 17

Axonotmesis

Question 18

Which nerve supplies the deltoid muscles?

Answer 18

Axillary nerve

so compression may cause weakness

Question 19

Posterior shoulder dislocations occur when a posterior force is exerted on an (abducted / adducted), (internally / externally) rotated shoulder.

Answer 19

adducted, internally rotated shoulder

Question 20

What X-ray sign is associated with posterior shoulder dislocations?

Answer 20

Light bulb sign

Question 21

What other joints of the shoulder girdle can dislocate?

Answer 21

Acromioclavicular joint

Sternoclavicular joint

Question 22

What ligaments may be disrupted by an AC joint dislocation?

Answer 22

Coracoclavicular ligaments

Question 23

What is the usual mechanism of AC joint dislocation?

Answer 23

Fall onto shoulder

Question 24

In which directions can the sternoclavicular joints dislocate?

Answer 24

Anteriorly

Posteriorly

Question 25

What structures can be compressed if the sternoclavicular joint dislocates posteriorly?

Answer 25

**Trachea** **Oesophagus** **Brachiocephalic vein**

Question 26

What symptoms may patients with a posterior SC joint dislocation present with?

Answer 26

**Pain** **Dyspnoea** **Dysphagia** **Venous congestion** (swelling)

Question 27

Pure elbow dislocations have a ___ prognosis.

Answer 27

**good**

Question 28

What is a **Monteggia** fracutre?

Answer 28

**Fractured ulna with a dislocated radial head @ elbow joint**

Question 29

What is a **Galeazzi** fracture?

Answer 29

**Fractured radius with a dislocated ulna @ DRU joint**

Question 30

What carpal dislocation is commonly missed on imaging and must be treated quickly?

Answer 30

**Perilunate dislocation**

Question 31

What finger joint can dislocate and cause deformity?

Answer 31

**PIP joint**

Question 32

Describe a) Swan neck b) Boutonniere's deformities?

Answer 32

**a) Swan neck** - DIP flexion, PIP hyperextension **b)** **Boutonniere's** - DIP hyperextension, PIP flexion

Question 33

What aspect of the pelvis can fracture in a hip dislocation?

Answer 33

**Posterior wall of the acetabulum**

Question 34

What is the big risk of hip dislocation?

Answer 34

**AVN of femoral head**

Question 35

Which nerve can be damaged by hip dislocation?

Answer 35

**Sciatic nerve**

Question 36

The hip joint usually dislocates **(anteriorly / posteriorly)**.

Answer 36

**posteriorly**

Question 37

What joint arthroplasty is known to dislocate?

Answer 37

**THRs**

Question 38

How are hip dislocations treated?

Answer 38

**Reduced** **Fixed** **Physio for early mobility**

Question 39

What is a common knee dislocation in adolescents?

Answer 39

**Patellar dislocation**

Question 40

In which direction does the patella usually dislocate?

Answer 40

**Laterally**

Question 41

If a bone breaks during a knee/patellar dislocation, what will occur?

Answer 41

**Lipohaemarthrosis** bloody fluid in the knee causing effusion and severe pain

Question 42

Patellar dislocations commonly \_\_\_.

Answer 42

**recur**

Question 43

What can be compromised in a full blown knee dislocation?

Answer 43

**Popliteal artery** **Common fibular nerve** **Virtually all of the ligaments**

Question 44

What complication, caused by swelling, may occur following a knee dislocation?

Answer 44

**Compartment syndrome**

Question 45

How are knee dislocations treated?

Answer 45

**Reduce** **Fix** +/- revascularisation, ligament reconstruction

Question 46

Which tarsal bone is at high risk of AVN?

Answer 46

**Talus**

Question 47

What is a fracture-dislocation of the TMT joint called?

Answer 47

**Lisfranc fracture-dislocation**