Clinical conditions of the shoulder

Question 1

What are the majority of shoulder dislocations? What position is the arm held in?

Answer 1

Anterior
(anteroinferiorly = as inf. aspect weak)
Ext. rotation, abduction

Question 2

What is the injury mechanism for an anterior shoulder dislocation?

Answer 2

Arm in abuction + ext. rotation (hand behind head) + arm forced post.
Direct blow to post. shoulder

Question 3

What is a Bankart lesion/labral tear?

Answer 3

Force of humeral head dislocating = tear part of glenoid labrum

Question 4

What is a Hill-Sachs lesion?

Answer 4

Indentation fracture in posterolateral humeral head as post. humeral head jammed against ant. lip of glenoid fossa
Due to ant. dislocation + tone of infraspinatus + teres minor

Question 5

What is the injury mechanism for a posterior dislocation?

Answer 5

Violent muscle contraction from epileptic seizure/lightning strike
Blow to ant. shoulder
Arm flexed across body + pushed post.

Question 6

What position is the patient in with a post. dislocation?

Answer 6

Internally rotated, adducted arm
Flattening/squaring of shoulder, prominent coracoid process
Can’t externally rotate to anatomical position
(rotator cuff tears, fractures, Hill-Sachs lesions)

Question 7

What is the mechanism of injury for an inferior dislocation? What are the associated injuries?

Answer 7

Forceful traction when arm hyperabducted over head

Rotator cuff tears, nerve/blood vessel injury

Question 8

What are the 5 common complications of shoulder dislocation?

Answer 8

Recurrent dislocation (damage to stabilising tissue, glenoid labrum + increased OA risk as humeral head damage)
Axillary artery damage (haematoma, absent pulses, cool limb)
Axillary nerve injury (supplies deltoid + overlying skin = regimental badge area)
Fractures (traumatic injury/1st dislocation, over 40)
Rotator cuff muscle tears (older people)

Question 9

Where are the majority of clavicle fractures? What is the mechanism of injury and how are they treated?

Answer 9

Middle 1/3rd (mid-clavicular)
Fall onto shoulder or FOOSH
Treat conservatively (or surgery = complete displacement, severe displacement with puncture, open fracture, floating shoulder = clavicle fracture + ipsilateral glenoid neck fracture)

Question 10

What happens to the position of the arm and clavicular fragments in a displaced mid-clavicular fracture?

Answer 10

Sternocleiodomastoid muscle elevates medial segment
Shoulder drops as trapezius can’t hold lateral segment up
Adduction by pec. major

Question 11

What nerves may be damaged by a clavicle fracture?

Answer 11

Suprascapular nerve

Supraclavicular nerve = ant. upper chest paraesthesia (C3 + C4)

Question 12

What is the most common rotator cuff tear?

Answer 12

Supraspinatus TENDON, beneath coracoacromial arch

Question 13

Why are most rotator cuff tears chronic?

Answer 13

Extended use with poor biomechanics/muscular imbalance/age-related degeneration (blood supply to muscles decrease = impaired ability to repair minor injuries = degenerative-microtrauma model with inflammatory cells + ox. stress = tenocyte apoptosis)

Question 14

What is the most common presentation of a rotator cuff tear?

Answer 14

Anterolateral shoulder pain, radiates down arm
Pain when lean on elbow + push down
Shoulder pain when reaching forward
Weakness of shoulder abduction

Question 15

What is impingement syndrome?

Answer 15

Supraspinatus tendon impinges on coraco-acromial arch = irritation/inflammation
From thickening of ligament/inflammation of tendon/subacromial osteophytes = narrows space

Question 16

What is the pain in impingement syndrome?

Answer 16

Shoulder abducted/flexed = space narrows
Dull pain, grinding with shoulder movement
Painful arc between 60-120 degrees abduction

Question 17

What is calcific supraspinatus tendinopathy? What are the symptoms?

Answer 17

Macroscopic deposits of hydroxyapatite in supraspinatus tendon
Pain with shoulder abduction/flexing arm + mechanical symptoms (stiffness, reduced range shoulder movement)

Question 18

What causes calcific supraspinatus tendinopathy?

Answer 18

Regional hypoxia = tenocytes to chondrocytes = cartilage then calcium deposits
OR
Ectopic bone formation from metaplasia of MSCs to osteogenic cells

Question 19

When is the most pain during calcific supraspinatus tendinopathy?

Answer 19

Reabsorption by phagocytes (look like toothpaste = cloudy on x-ray)

Question 20

What is adhesive capsulitis?

Answer 20

Frozen shoulder

Capsule of glenohumeral joint inflamed + stiff = chronic pain (worse @ night, cold weather)

Question 21

What are some risk factors for frozen shoulder?

Answer 21

Autoimmune

Female, diabetes mellitus, thyroid disease, CVD

Question 22

How is frozen shoulder treated?

Answer 22

Physio, analgesia, anti-inflammatory

Manipulation under analgesia = break up scar tissue to restore range of motion

Question 23

What joint does shoulder OA most commonly affect? How is it treated?

Answer 23

Acromioclavicular joint
(Same as OA for others)
Arthroscopy = remove loose pieces damaged cartilage
Hemiarthroplasty (replacement of humeral head)/total shoulder replacement

Question 24

How does a fractured surgical neck of the humerus occur?

What neurovascular structures are at risk?

Answer 24

Blunt trauma to shoulder or FOOSH

Axillary nerve, post. circumflex artery

Question 25

What is the popeye sign caused by?

Answer 25

Rupture of biceps tendon

Little weakness in upper limb due to action of brachialis/supinator muscles