Week 1: Subacromial Impingement Syndrome Flashcards
What is the most common condition of the shoulder that patients seek medical management?
Rotator cuff disease
At what age and activity level does rotator cuff disease occur?
Any age and activity level
According to the medical community, is rotator cuff disease from a single cause?
No, it is multifactorial
RCD classifications
- Tendon degeneration
- Tear to avascular region
- Impingement
- Trauma/instability
How does the process of tendon degeneration occur?
- Fibroblasts undergo senescence and apoptosis
- The fibers lose their parallel organization and fray
- Tendon swells, making it susceptible to further damage
Senescence
The condition or process of deterioration with age
Apoptosis
The death of cells which occurs as a normal and controlled part of an organism’s growth or development
What is the critical zone of the tendon?
Region with low blood flow on the tendon
Where is the critical zone of the supraspinatus?
~10 mm from the distal attachment on the humerus
Impingement classifications
- Primary
- Secondary
- Internal
What is primary impingement?
- Impingement is the primary problem
- Mechanical impingement b/t the GH joint and subacromial space
- Associated AC joint problems
What role does strength imbalance play in primary impingement of the shoulder?
If the supraspinatus and deltoid are imbalanced, the humerus might flight superiorly
Structures involved in primary impingement?
- RC tendons
- Long head of biceps
- GH joint capsule
- Subacromial bursa
- Subacromial arch
What causes primary impingement?
- RC tendinopathy
- Posterior capsule tightness
- Morphology of the acromion
- Postural dysfunction
- Hooked acromion
Acromial types
- Type 1
- Type 2
- Type 3
Type 1 acromion
Large area available for tendons and bursa
Type 2 acromion
Small area available for tendons and bursa
Type 3 acromion
- Small area available for tendons and bursa
- Hooked acromion
Neer classification for SIS
- Stage 1
- Stage 2
- Stage 3
Stage 1 SIS Neer Classification
- Edema and hemorrhage
- <25
- Reversible
- Conservative treatment
Stage 2 SIS Neer Classification
- Fibrosis and tendinopathy
- 25-40
- Recurrent pain
- Consider subacromial decompression (SAD)
Stage 3 SIS Neer Classification
- Bone spurs and tendon rupture
- > 40
- Progressive disability
- Surgical management
Secondary impingment
Impingement is due to underlying instability
Internal impingement
- AKA undersurface impingement
- Occurs at 90+ degrees ER and 90 degrees ABD
- Inferior surface of supra/infraspinatus contacts glenoid rim
Structures involved in internal impingement
- Supra/infraspinatus
- GH joint capsule
- Subacromial bursa
Causes of internal impingement
- Capsular laxity
- RC weakness
- Scapular dyskinesia
- Poor throwing mechanics
Test item cluster for SIS (Park et al.)
- Hawkins-Kennedy Test
- Painful arc sign
- Infraspinatus muscle test
Patient presentation for SIS
- Pain at night
- Pain w/ OH activities
- Complaints of stiffness
Hawkins-Kennedy Test
- Elbow flexed
- IR
- Horizontal ADD
Painful arc sign
- Patient actively elevates the arm in the scapular plane
- Sign of RC tendon pathology when patient hikes shoulder during ABD
Infraspinatus muscle test
Pain on resisted ER
Neer’s Test
- Pt sitting
- One hand depresses scapula
- IR pt arm
- Forced forward flexion
- Positive test is pain
Empty Can (Jobe)
- Standing or sitting
- Arms elevated to 90 degrees in scapular plane
- Full IR
- Downward force applied
- Positive test is weakness or pain
Patient presentation for secondary SIS
- Young
- History of instability
- Pain w/ OH
- Generalized laxity
- OH reaching increases symptoms
Objective findings for secondary SIS
- Scapular dyskiinesis
- Weakness or scapular stabilizers
- Hypermobility of anterioir capsule
- instability tests
Patient presentation for internal SIS
- Athlete
- Pain OH reaching, throwing
- Aching posterior shoulder
Objective findings for internal SIS
- +posterior impingement test
- +instability tests
- Scapular dyskinesis
- Weakness of scapular stabilizers
- Hypermobility anterior capsule
Best exercises to manage scapular dyskinesis
- Forward in side-lying
- Horizontal ABD w/ ER
- Side-lying ER
- Prone extension
Clinical prediction rule via logistic regression analysis
- Pain-free shoulder flexion <127
- Shoulder IR <53 at 90 degree ADB
- Negative Neer test
- Not taking meds for pain
- Symptoms < 90 days
