2 Subacromial Impingement

Question 1

What is the etiology of RC disease?

Answer 1

• Tendon Degeneration
• Tear to Avascular Region
• Impingement
• Trauma/Instability

Question 2

What happens in tendon degernation?

Answer 2

Fibroblasts undergo senescence and apoptosis

loss of parallel organization

Frayed tendon

Swelling in tendon

Question 3

What is the critical zone of the supraspinatus?

Answer 3

Codman’s Critcal zone

• 10mm from distal attachment of humerus
• narrowing of vessels and lumen due to stress
• injury + degernative changes

Question 4

Primary Impingement

Answer 4

Mechancial

Altered/reduced subacromial space

AC problems

Strength embalance of RC and deltoid (force couple)

Structures:

RC tendons, Long Head Biceps, GH capsule, Subacromial bursa/arch

Question 5

What are the causes of Primary Impingement?

Answer 5

RC tendinopathy

Posterior capsule tightness

Morphology of acromion

Postural dysfunction

Hooked acromion

Question 6

Neer classification (3 stages)

Answer 6

1. Edema + hemorrahage (early impingement <25 years old, reversible, conservative management)
2. Fibrosis & tendinopathy (25-40 years, recurrent pain, consider SAD)
3. Bone spurs and tendon rupture ( >40 years progressive disability, surgical management)

Question 7

Secondary Impingement

Answer 7

Due to underlying instability

Uncertain GH positioning

Scapular dyskinesia

SECOND LACKS STABILITY

Question 8

Internal Impingement

Answer 8

Undersurface impingement

at 90 deg ER + 90 Abd as inferior surface of supra/infraspinatus contact the glenoid rim

Throwing sports

Question 9

Internal Impingement Causes

Answer 9

Capsular laxity

RC weakness (improper forces)

Scapular Dyskinesia

Poor throwing mechanics

Question 10

Structures of Internal Impingement

Answer 10

Subacromial bursa

Supra/infraspinatus

GH capsule

Question 11

Patient presentation of Impingement

Answer 11

• Pain at night
• pain with OH activities
• Stiffness - hard to reach over head, tuck in shirt

(pain in upper lateral arm - deltoid and humerus meets)

• more pronounce at the end of the day

Question 12

Test item cluster for impingement

Answer 12

Hawkins Kennedy

Painful Arc sign

Infraspinaturs muscle test

(shoulder hike in attempt to flex or abd arm)

Question 13

Patient presentation for secondary impingement syndrome?

Answer 13

Young, history of instablity, pain with OH activities, general laxity, OH reaching increases symptoms

Objective findigs: Scapualr dyskinesis, weakess of scapular stabilizers, hypermobility of anterior capsule , +instability test

Question 14

Special test for SIS

Answer 14

• Hawkins kennedy
• Neer
• Painful Arc
• Empty can
• ER resitance

Question 15

Internal SIS presentation

Answer 15

• Athete, pain OH reaching/throwing, arching posterior shoulder

Objective findings: +ve impingement, +ve instability test, scapular dyskinesis, weakness of scap stabilizers, hypermobility anterior capsule

Question 16

What is the typical abnormal scapular motion of scapular dyskinesis?

Answer 16

high activity -> upper trap

Low activity -> lower trap/SA