Common Dislocations

Question 1

what is the most common cause of dislocation?

Answer 1

trauma

Question 2

where can the shoulder dislocate?

Answer 2

anterior - most common
posterior
inferior - rare

Question 3

who is shoulder dislocation most common in?

Answer 3

young adults - esp females

Question 4

what is an anterior shoulder dislocation and what causes it?

Answer 4

humeral head is anterior to the glenoid

caused by fall with shoulder in external rotation

Question 5

how do you assess axillary nerve?

Answer 5

assess sensation in regimental badge area

- often damaged in anterior shoulder dislocation

Question 6

what is a posterior shoulder dislocation and what causes it?

Answer 6

humeral head posterior to glenoid

caused by fall with shoulder in internal rotation or direct blow to anterior shoulder

Question 7

X ray sign of posterior shoulder dislocation?

Answer 7

light bulb sign

Question 8

what is an inferior shoulder dislocation and what causes it?

Answer 8

humeral head inferior to glenoid

arm held in abduction

Question 9

what must be done if inferior dislocation of shoulder?

Answer 9

NV assessment and reduction

Question 10

how is shoulder dislocation managed?

Answer 10

closed reduction under sedation
open reduction
stabilisation and rehabilitation

Question 11

possible reduction methods?

Answer 11

hippocratic

in line traction

Question 12

what affects instability of shoulder after dislocation?

Answer 12

age at time of dislocation

- younger = higher risk of instability

Question 13

what usually causes elbow dislocation?

Answer 13

fall onto outstretched hand

Question 14

how can an elbow dislocate and who does this usually occur in?

Answer 14

posterior
anterior
medial
lateral
occurs in adults and children

Question 15

risks with elbow dislocation?

Answer 15

radial head or coronoid process fracture

Question 16

what moves in elbow dislocations?

Answer 16

ulna/radius

- humerus stays the same

Question 17

what is a pulled elbow?

Answer 17

radial head dislocation/possible elbow dislocation due to arm being pulled upwards

Question 18

how do you manage elbow dislocation?

Answer 18

closed reduction under sedation
open reduction is rare
2 weeks in sling and rehab

Question 19

reduction methods in elbow?

Answer 19

traction in extension +/- pressure over olecranon

Question 20

common mechanism of interphalangeal joints dislocations?

Answer 20

hyperextension injury
direct axial blow
- almost always dislocates posteriorly

Question 21

possible pitfalls in IP joint dislocation?

Answer 21

head of phalanx button-holes through volar plate

recurrent instability due to associated fracture

Question 22

how can you assess neurovasculature in the hand/fingers?

Answer 22

cap refill - compare to unaffected finger

assess sensation

Question 23

how is IP joint dislocation managed?

Answer 23

closed reduction under digital or metacarpal block
open reduction = rare
2 weeks neighbour strapping
volar slab in edinburgh position if unstable

Question 24

reduction methods for IP joints?

Answer 24

in line traction + corrective pressure

Question 25

where is anaesthesia applied for finger reduction?

Answer 25

in web space | gives specific numbness only in the finger

Question 26

what is the edinburgh position?

Answer 26

position of safety | prevents contracture of tendons

Question 27

what commonly causes patella dislocation and how does it dislocate usually?

Answer 27

sudden quads contraction with a flexing knee almost always lateral in teenage girls

Question 28

what is patella dislocation associated with?

Answer 28

hypermobility under-developed lateral femoral condyle increased Q angle (valgus, femoral neck anteversion) lateral quads insertions or weak vastus medialis

Question 29

how do you assess Q angle?

Answer 29

line 1 = from ASIS to middle of patella line 2 = tibial tubercle to middle of patella angle between lines = Q angle

Question 30

problems in which structure can predispose to lateral patella dislocation?

Answer 30

medial retinaculum

Question 31

how does patella dislocation present?

Answer 31

``` can have medial knee pain clear lateral dislocation often self relocating effusion (haemarthrosis) patella apprehension test +ve ```

Question 32

how is patella dislocation managed?

Answer 32

``` reduce with knee extension radiographs aspiration brace physio surgical if recurrent dislocation - lateral release/medial reefing - patella tendon realignment - replace MPFL with graft ```

Question 33

what causes knee dislocation?

Answer 33

high velocity injuries | low velocity injuries - if knee goes back on itself after dislocation

Question 34

how can a spontaneously relocated knee dislocation injury diagnosed if normal X ray?

Answer 34

lateral collateral ligament injury + fibular nerve injury = dislocation

Question 35

how can the knee dislocate?

Answer 35

anterior posterior rotational, medial, lateral

Question 36

risk with posterior knee dislocation?

Answer 36

damage to popliteal artery

Question 37

how is a knee dislocation assessed?

Answer 37

popliteal artery/vein injury (may not be obvious - intimal tear or thrombus) nerve injury - peroneal nerve ligamentous stability - examination under anaesthetic normal exam = observe in hospital clinical concern = arteriogram/MRI

Question 38

urgent management of knee dislocation?

Answer 38

``` reduction under sedation - may need open reduction if condyle button-holed through capsule stabilise in splint or external fixation plain radiographs MRI ```

Question 39

early knee dislocation surgery?

Answer 39

``` vascular repair (6 hr window) nerve repair ```

Question 40

definitive knee dislocation surgery? what are the risks with this?

Answer 40

``` sequential ligamentous repair complications - arthrofibrosis and stiffness - ligament laxity - nerve or arterial injury ```

Question 41

what usually causes native hip dislocation? and which direction does it dislocate?

Answer 41

high velocity injury (RTA, fall from height etc) | - usually posterior

Question 42

what other injuries is hip dislocation associated with?

Answer 42

posterior acetabular wall or femoral fracture

Question 43

how does hip dislocation present?

Answer 43

hip flexed and internally rotated with knee adducted

Question 44

early management of hip dislocation?

Answer 44

``` NV assessment (esp. sciatic nerve) radiographs urgent reduction stabilise in traction if required further imaging (CT) ```

Question 45

definitive management of hip dislocation? what are the risks?

Answer 45

``` fixation of associated pelvic fractures fixation of other injuries in poly-trauma complications - sciatic nerve palsy - avascular necrosis of femoral head - secondary osteoarthritis of hip ```