Common Dislocations

Question 1

Where are common sites of dislocations?

Answer 1

Elbow, hip, shoulder, IP joints, patella, knee

Question 2

What are common features of the history and examination in all dislocations?

Answer 2

Trauma = fall, RTA, sports injury, seizure
Inspection for deformity
Palpating = vascular supply, neurology

Question 3

What are the common mechanics of shoulder dislocations, and what directions can the dislocations go in?

Answer 3

Fall, traction injury, common in young adults

Directions = anterior (most common), posterior, inferior (rare)

Question 4

What are some features of an anterior shoulder dislocation?

Answer 4

Fall with shoulder in external rotation, humeral head anterior to glenoid, needs regimental badge area sensory assessment (axillary nerve)

Question 5

What are some features of posterior shoulder dislocations?

Answer 5

Fall with shoulder in internal rotation, direct blow to anterior shoulder, humeral head posterior to glenoid

Question 6

What are some features of inferior shoulder dislocations?

Answer 6

Arm held in abduction, humeral head inferior to glenoid, needs prompt neurovascular assessment and reduction

Question 7

What are some management options for shoulder dislocations?

Answer 7

Closed reduction under sedation, open reduction, stabilisation and rehabilitation
Reduction methods = Hippocratic, in-line traction

Question 8

What is a complication of shoulder dislocations?

Answer 8

Recurrent instability risk = related to age, risk of recurrence decreases with age

Question 9

How do elbow dislocations arise, and in what direction can it be dislocated?

Answer 9

Mechanism = fall onto outstretched hand
Directions = anterior, posterior, medial/lateral
Occurs in adults and children

Question 10

What are some risks associated with elbow dislocations?

Answer 10

Small risk of radial head or coronoid process fracture

Low risk of recurrence

Question 11

How should elbow dislocations be managed?

Answer 11

Closed reduction under sedation, open reduction rarely required, 2 weeks in sling and rehabilitation
Reduction methods = traction in extension +/- pressure over olecranon

Question 12

What are some features of interphalangeal (IP) dislocations?

Answer 12

Mechanism = hyperextension, direct axial blow

Always displaced posteriorly

Question 13

What are some complications of IP dislocations?

Answer 13

Head of phalanx button holes through volar plate, recurrent instability due to associated fracture

Question 14

How should interphalangeal dislocations be managed?

Answer 14

Closed reduction under digital/metacarpal block, open reduction rarely required, 2 weeks in neighbouring strapping, volar slab in Edinburgh position if unstable

Question 15

What reduction methods can be used to treat IP dislocations?

Answer 15

In-line traction plus corrective pressure

Question 16

What are some features of patellar dislocations?

Answer 16

Mechanism = sudden quads contraction with a flexing knee
Always displaced laterally
Most common in teenagers, more common in girls

Question 17

What are some causes of patellar dislocations?

Answer 17

Hypermobility, under-developed (hypoplastic) lateral femoral condyle, increased Q angle, genu valgum, increased femoral neck anteversion, lateral quads insertion or weak vastus medialis

Question 18

How do patients present with a patellar dislocation?

Answer 18

Clear history of patella dislocating laterally, often self-relocating

Question 19

What would you expect to find on examination of a patient with patellar dislocation?

Answer 19

Pain medially = from torn medial retinaculum
Effusion = haemarthrosis
Positive patellar apprehension test

Question 20

How are patellar dislocations treated?

Answer 20

Reduce with knee expansion, radiographs, aspiration, brace, physio
Surgery for repeat dislocations = lateral release/medial reefing, patella tendon realignment

Question 21

How do knee dislocations occur and who gets them?

Answer 21

Mechanism = high or low velocity injuries

Most common in teenagers, more common in girls

Question 22

Why are knee dislocations missed, and why is it important that they are discovered?

Answer 22

May spontaneously relocate = lateral collateral ligament or peroneal nerve may be injured in initial dislocation

Question 23

What should you do in a patient with a normal examination but high clinical suspicion of a knee dislocation?

Answer 23

Observe in hospital and get arteriogram/MRI

Question 24

What structures may be damaged in a knee dislocation?

Answer 24

Peroneal nerve

Popliteal artery and vein = may not be obvious (intimal tear/thrombus)

Question 25

How should ligamentous stability be examined in a patient with a knee dislocation?

Answer 25

Under anaesthetic

Question 26

What is the urgent management for a knee dislocation?

Answer 26

Reduction under sedation, may require theatre reduction if condyle has button-holed through capsule, stabilise in splint or external-fixation

Question 27

What methods are used to image a dislocated knee?

Answer 27

Plain radiographs, MRI

Question 28

What surgery can be done for knee dislocations?

Answer 28

Early surgery = vascular repair (6hr window), nerve repair

Definitive surgery = sequential ligamentous repair

Question 29

What are some potential complications of a knee dislocation?

Answer 29

Arthrofibrosis and stiffness, ligament laxity, nerve or arterial injury

Question 30

What are some features of a hip dislocation?

Answer 30

Mechanism = RTA dashboard injury, fall from height
Most commonly posteriorly displaced
Associated fractures = posterior acetabulum wall, femoral

Question 31

How di hip dislocations present?

Answer 31

Flexed, internally rotated and adducted knee

Question 32

What is the early management of a hip dislocation?

Answer 32

Neurovascular assessment (especially sciatic nerve)
Radiographs (changes can be subtle)
Urgent reduction and stabilise in tractions if needed
Further imaging with CT

Question 33

What is the definitive management for a hip dislocation?

Answer 33

Fixation of associated pelvic fractures

Fixation of other injuries in poly-trauma patients

Question 34

What are some complications of hip dislocations?

Answer 34

Sciatic nerve palsy, avascular necrosis of femoral head, secondary osteoarthritis of hip