Shoulder Instability

Question 1

What are the passive stabilizing mechanisms for the GH jt?

Answer 1

Bony geometry
Glenoid labrum
Limited joint volume
Negative intra-articular pressure
Adhesion and cohesion
Capsuloligamentous structure

Question 2

What are the 3 mechanisms in which stability of the GH joint are achieved?

Answer 2

1) joint compression - concave/convex surfaces
2) synergistic, coordinated contraction of the RTC muscles
3) dynamization or tensioning of the GH ligaments through the direct attachment or blending of the RTC into the glenohumeral capsule and ligaments.

Question 3

What fracture is common in a posterior dislocation?

Answer 3

Lesser tuberosity

Question 4

How much can the labrum contribute to the glenoid fossa’s depth?

Answer 4

50%

Question 5

What does TUBS stand for?

Answer 5

Traumatic onset
Unidirectional (anterior)
Bankart lesion (usually present)
Surgery

Question 6

AMBRI

Answer 6

A atraumatic 
M multidirectional 
B bilateral
R rehabilitation 
I interior capsular shift - procedure of choice

Question 7

ALPSA

Answer 7

A anterior
L labroligamentous
P periosteal 
S sleeve
A avulsion

Traumatic anterior dislocation characterized by the labrum and periosteal sleeve of the anterior glenoid being avulsed and displaced medially

Question 8

HAGL

Answer 8

H humeral
A avulsion of the
G glenohumeral
L ligament

Traumatic dislocation when forced into a hyperabducted position

Question 9

What special test for instability are most sensitive?

Answer 9

Anterior release

Load-shift (under anesthesia)

Question 10

What special test for shoulder instability are most specific?

Answer 10

Apprehension
Anterior release
Load-shift (under anesthesia)

Question 11

How much anterior translation of the humeral head is considered normal?

Question 12

What is the Hawkins grading system to assess increased glenohumeral translation?

Answer 12

Grade I - humeral head is felt ride up the face of the glenoid rim ~50% translation
Grade II - clinical subluxation
Grade III - clinical dislocation

Question 13

What is a Bankart lesion?

Answer 13

Avulsion or detachment of the anterior portion of the inferior glenohumeral ligament complex and glenoid labrum off the anterior rim of the glenoid.

Question 14

What are he incidences of the recurrent dislocations?

Answer 14

40 yo under 10%

More common in males than females and most reoccurs cry seen within the first 2 years.