Dislocations

Question 1

What is a dislocation?

Answer 1

-separation/laxity of articulating surfaces
-risk of recurrent injury (redislocation)

Question 2

What is the difference between dislocation and subluxation?

Answer 2

Dislocation = complete dissociation of articulating joint surfaces
Subluxation = articular surfaces partially in contact

Question 3

What are common minor dislocations in body?

Answer 3

Fingers
-proximal interphalangeal most frequent - in ball handling sports
Toes
- 2nd toe most frequently dislocated (from stubbed or kicking)

Question 4

What dislocation involves…
- direct impact/non contact force
- >99% LAT displacement
- more common in females
- located in trochlear dysplasia

Answer 4

Patella with common injury to patella alta tendon

Question 5

What are joint locations for major dislocations?

Answer 5

Shoulder - most common ANT dislocation
Hip (rare in sport) - most common POS dislocation (femur ADD INT ROT). Associated with femoral head/neck fractures

Question 6

What are acute injuries of tissue unions?

Answer 6

• Osseo-chrondral, Osseo-ligamentous, chrondro-ligamentous injuries
  -disassociation/instability/dysfunction of tissue complexes

Question 7

What happens in a TFCC injury?

Answer 7

Triangular Fibrocartilage Complex injury
- absorbs ~20% axial load across wrist joint causing distal radio-ulnar instability
- commonly caused by FOOSH and compressive loading (gymnastics, weightlifting, racket sports)

Question 8

What happens in Scapholunate dissociation?

Answer 8

• Injury to scapholunate ligament
• caused by FOOSH
  -~15% distal radius fractures are associated
• most common form of caparl instability
• Rx = ligament reconstruction to return grip strength/pain relief
• increased risk of developing OA / SLAC (scapholunate advanced collapse wrist)

Question 9

What happens in a sternoclavicular joint injury?

Answer 9

• only articulation with UB limbs and axial skeleton
• ANT dislocation more common
• “retrosternal” = POS dislocations
  ~30% associated with injury to brachial plexus, vessels, trachea

ANT SCJ dislocations
- MED clavicle end can be palpable and prominent
- subluxation may occur after failed healing of ligamentous structures