Common Shoulder Conditions

Question 1

Who is likely to get a dislocated shoulder?

Answer 1

• Approximately 1.7% of the population will experience a dislocated shoulder.
• Bimodal distribution:
– 20-30 years (Male:Female 9:1)
– 61-80 years (Male:Female 1:3)
• Less common in children as their epiphyseal plate is weaker and
tends to fracture before dislocating
• More common in elderly: reduced collagen crosslinking → weaker capsule / tendons / ligaments

Question 2

-

Answer 2

-

Question 3

What contributes to the stability of the glenohumeral joint?

Answer 3

• Congruency of humeral head in glenoid
fossa and glenoid labrum
• Negative intra-articular pressure (‘suction cup’ effect)
• Static stabilisers e.g. labrum, joint capsule, extra-capsular
ligaments
• Dynamic stabilisers e.g. rotator cuff muscles, long head of biceps brachii

Question 4

Why is the glenohumeral joint weak inferiorly?

Answer 4

Not much support inferiorly - no muscles there

Question 5

Describe anterior dislocation

Answer 5

• 90% of dislocations are anterior; two subtypes:
– Subcoracoid (60%): Head of humerus lies anterior to glenoid fossa, inferior to coracoid
– Subglenoid (30%): Head of humerus lies antero-inferior to glenoid
– Humeral head dislocates antero-inferiorly
– Disruption of glenohumeral ligaments- they are torn through
– Head pulled anteriorly by muscles (subscapularis, pectoralis major)

Question 6

What is the anterior dislocation mechanism?

Answer 6

• “Hand behind head” =most common
– Abduction
– External rotation 
• Trauma pushes arm posteriorly 
• Humeral head dislocates antero-inferiorly OR 
• Direct blow to posterior shoulder

Question 7

What is the clinical presentation of anterior dislocation?

Answer 7

• prominent acromium = squaring of the shoulder
• fullness due to numerous head popping out anterior-inferiorly
• patient holds the weight of their ar with the other hand when elbow flexed

Question 8

What is a bankart lesion ?

Answer 8

• Tear of glenoid labrum +/- glenoid fracture

Question 9

What is a Hill-Sachs lesion?

Answer 9

• Anterior dislocation
• Posterior aspect of humeral head jammed against anterior lip of glenoid
– Held tightly by muscles e.g. infraspinatus - pulled back forcefully against glenoid lip
• Indentation fracture = ‘dent’
• 50% of patients aged <40 yr with anterior dislocation
• 80% of patients with recurrent dislocation

Question 10

What are the mechanisms of posterior dislocation

Answer 10

• 2-4% of cases Mechanisms:
• Violent muscle contraction
– Epileptic seizure 
– Electrocution 
– Lightning strike
• Blow to anterior shoulder
• Arm flexed across body and pushed posteriorly
Have a high index of suspicion for seizure, electrocution etc.

Question 11

What are the clinical signs of posterior dislocation

Answer 11

• Squaring of shoulder (loss of normal contour)
• Arm adducted and internally rotated
• Prominent coracoid process anteriorly
• Humeral head may be prominent posteriorly

Question 12

Describe the radiology of posterior dislocation

Answer 12

• Can be missed on AP X-ray as looks ‘in joint’
• ‘Light bulb’ sign
• Increased glenohumeral distance

Question 13

What is inferior dislocation?

Answer 13

• Rare ≈ 0.5% of cases
• Hyperabduction injury
• High rate of associated
injuries:
– Nerves 60% 
– Rotator cuff 80% 
– Vascular 3%
Violent injury - high rate of complication

Question 14

What are the complications of shoulder dislocation?

Answer 14

• Recurrent dislocation
– 60% overall risk
– Risk decreases with age (↓ elasticity of capsule, ligaments etc.)
• Axillary artery damage
– More common in elderly
• Nerve injuries
– Axillary nerve most common
– Cords of brachial plexus
– Other branches e.g. musculocutaneous
• Fractures
– Most common during first-time dislocation
– Humeral head, greater tubercle, clavicle, acromion
• Rotator cuff tears
– More common in elderly and after inferior dislocation
Axillary n.

Question 15

Describe the anatomy of the clavicle

Answer 15

• S-shaped bone
• Acts as a strut between sternum and glenohumeral joint
• Lateral 1/3rd is flat
– Insertion of trapezius
– Origin of deltoid
• Middle 1/3rd is tubular
– Weak to axial load
• Medial 1/3rd is quadrangular
– Insertion of sternocleidomastoid
– Origin of pectoralis major (clavicular head)
• Protects apex of lung, subclavian vessels, and trunks & divisions of brachial plexus

Question 16

How is clavicle fracture treated?

Answer 16

• Most treated conservatively (in a sling)
• Some indications for surgical fixation:
– Complete displacement
– Severe displacement with tenting of skin (risk of conversion to open fracture if bone end pokes through
– Open fracture /
– Neurovascular compromise
– Interposed muscle
– Floating shoulder (clavicle # + glenoid neck #)

Question 17

What are the complications of clavicle fracture?

Answer 17

• Non-union 
• Malunion - unite in a bad place 
• Infection (if an open #) 
• Damage to nerves
– Suprascapular nerve - 1
– Supraclavicular nerves -3 (error in TMA)
– Trunks and divisions of brachial plexus
• Vascular
– Subclavian vein and artery 
• Apex of lung
– Pneumothorax

Question 18

What are rotator cuff tears?

Answer 18

• Rotator cuff:
– Supraspinatus
– Infrapspinatus
– Teres minor
– Subscapularis
Most common site for tear: 
• Supraspinatus under coraco-acromial arch

Question 19

Describe the pathology of rotator cuff tears

Answer 19

• Acute (following trauma) • Chronic
– Degenerative microtrauma model - any problem with the acromium can damage the supraspinatus tendons it comes underneath
Leads to inflammation etc
See slide for dagnra

Question 20

What are the risk factors for rotator cuff tears

Answer 20

• Age 
• Recurrent overhead activity
– Painters
– Carpenters
– Swimming
– Volleyball
– Tennis
– Weightlifting 
• Recurrent heavy lifting 
• OA shoulder with osteophytes
• Abnormally-shaped acromion

Question 21

What are supraspinatus tears?

Answer 21

• Can be asymptomatic
• Most commonly anterolateral shoulder pain, radiating down arm
• Precipitated by activity (can be present at rest)
– Above shoulder activity (abduction and external rotation)
– Leaning down on elbow (displaces humeral head superiorly)
– Pushing self out of a chair (displaces humeral head superiorly)
– Reaching forward (flexing shoulder) and lifting e.g. milk from fridge
• May also complain of weakness of shoulder abduction but often only found on examination

Question 22

What is impingement syndrome?

Answer 22

• Impinge = to rub or catch
• Rotator cuff tendons impinge on coraco-acromial arch
• Caused by anything that narrows subacromial space
– Thickening of coraco-acromial ligament
– Inflammation of supraspinatus tendon
– Subacromial osteophytes in OA
• Pain, weakness and reduced range of motion
• Pain exacerbated by overhead movement

Question 23

What is the painful arc?

Answer 23

When shoulder abducted
No pain up to 60o
Pain from 60-120o - due to phase when greater tuberosity negotiates the subacromial space - Due to narrowing of space - impingement
No pain superiorly to that

Question 24

What is calcification supraspinous tendonitis?

Answer 24

• Hydroxyapatite crystals in supraspinatus
tendon 
• Pain on abduction or flexion of shoulder
– Reduced coraco-acromial space 
• Mechanical ‘block’ to movement
– Stiffness
– Snapping sensation
– Catching
– Reduced range of movement

Question 25

Describe the pathology of calcification supraspinatus tendonitis?

Answer 25

• Multifactorial 
Theory 1: 
• Regional hypoxia 
• Tenocytes → chondrocytes 
• Endochondral ossification 

Theory 2:
• Metaplasia of mesenchymal stem cells into osteogenic cells
• Ectopic bone formation

Crystalline in resting phase
Reabsorbed by phagocytes (“toothpaste”) Reabsorption phase is most painful

Question 26

What is adhesive capsulitis?

Answer 26

“Frozen shoulder”
• Glenohumeral joint is inflamed and stiff
• Pain is constant, worse at night
• Exacerbated by movement and cold weather
• Possible autoimmune component, often triggered by trauma to shoulder

Question 27

What are the risk factors of adhesive capsulitis?

Answer 27

• Risk factors:
– Female gender
– Trauma to shoulder
• Acute 
• Calcific tendonitis 
• Rotator cuff tear
– Epilepsy with tonic seizures
– Diabetes mellitus (glucose binds to collagen) 
– Connective tissue disease 
– Thyroid disease (↑ and ↓) 
– Inactivity
• Stroke 
• Trauma 
• Illness

Question 28

Describe the treatment o frozen shoulder?

Answer 28

• Physiotherapy
• Analgesia
• Anti-inflammatory medication
• Sometimes manipulation under anaesthesia
• Usually resolves with time
• 90% of shoulder motion regained
• 6-17% risk in other shoulder within 5 years

Question 29

What is osteoarthritis of the shoulder?

Answer 29

-

Question 30

Give a treatment overview for

Answer 30

(Mild)
Non-pharmacological management - Education, activity modification
2. Non pharmacological management - physiotherapy, simple analgesia e.g. paracetamol
3. Pharmacological management - NSAIDS, opioids, glucosamine + chondroitin sulfate, steroid injection, visosupplementation
4. Surgery - arthroscopy, hemiarthroplasty - semi replacement, total shoulder replacement
(Severe)