Week 2: Shoulder Instability Flashcards
How many people does shoulder instability affect?
- As high as 2% of the population
- 3x more common in men than women
- Underestimate the true numbers, only include episodes of dislocation
What enhances shoulder stability?
- Labrum (bony congruency)
- Negative pressure in GH joint
- Muscle and tendons
- Ligaments and capsule
Differentiate b/t laxity and stability
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Instability classifications
- Traumatic
- Atraumatic
- Acquired
What is subluxation?
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What is dislocation?
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Bankart lesion
Tear of the glenoid labrum in anterior region of glenoid
Reverse Bankart lesion
Tear of the glenoid labrum in posterior region of the glenoid
Hill-Sachs lesion
Compression fracture of the humeral head occurring as result of traumatic dislocation anteriorly
Reverse Hill-Sachs lesion
Compression fracture of the humeral head occurring as result of traumatic dislocation posteriorly
What part of the humerus is affected in a Hill-Sachs lesion?
Posterolateral humerus
What part of the humerus is affected in a reverse Hill-Sachs lesion?
Anteromedial humerus
What direction of instability is most common?
- Anterior
- 90-95%
What are the characteristics of anterior instability?
- Unidirectional w/ traumatic onset
- ABD and ER
- May have a Bankart lesion w/ it
How common is posterior instability?
2-10%
What are the characteristics of posterior instability?
- Unidirectional w/ repetitive loading
- ADD and IR
- May have a reverse Bankart lesion w/ it
How common is multidirectional instability?
1-3%
What are the characteristics of multidirectional instability?
- Atraumatic
- Congenital or acquired laxity
Biceps tendon/SLAP lesions
May or may not be associated w/ GH instability
What kind of traumatic MOI occurs with anterior dislocation?
- Combo of abduction, extension, and posteriorly directed force on arm
- Fall on an outstretched hand is common MOI for elderly
MOI for atraumatic injury to shoulder
- Anatomical anomaly
- General laxity
- Poor muscle balance
- Scapular dyskinesis
- Connective tissue diseases
Scapular dyskinesis
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Connective tissue diseases of the shoulder
- Ehlers-Danlos Syndrome
- Marfan Syndrome
Ehlers-Danlos Syndrome
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Marfan Syndrome
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