Common Shoulder Conditions Flashcards
Who is likely to get a dislocated shoulder?
• 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
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What contributes to the stability of the glenohumeral joint?
• 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
Why is the glenohumeral joint weak inferiorly?
Not much support inferiorly - no muscles there
Describe anterior dislocation
• 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)
What is the anterior dislocation mechanism?
• “Hand behind head” =most common – Abduction – External rotation • Trauma pushes arm posteriorly • Humeral head dislocates antero-inferiorly OR • Direct blow to posterior shoulder
What is the clinical presentation of anterior dislocation?
- 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
What is a bankart lesion ?
• Tear of glenoid labrum +/- glenoid fracture
What is a Hill-Sachs lesion?
• 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
What are the mechanisms of posterior dislocation
• 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.
What are the clinical signs of posterior dislocation
- Squaring of shoulder (loss of normal contour)
- Arm adducted and internally rotated
- Prominent coracoid process anteriorly
- Humeral head may be prominent posteriorly
Describe the radiology of posterior dislocation
- Can be missed on AP X-ray as looks ‘in joint’
- ‘Light bulb’ sign
- Increased glenohumeral distance
What is inferior dislocation?
• 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
What are the complications of shoulder dislocation?
• 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.
Describe the anatomy of the clavicle
• 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
How is clavicle fracture treated?
• 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 #)
What are the complications of clavicle fracture?
• 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
What are rotator cuff tears?
• Rotator cuff: – Supraspinatus – Infrapspinatus – Teres minor – Subscapularis Most common site for tear: • Supraspinatus under coraco-acromial arch
Describe the pathology of rotator cuff tears
• 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
What are the risk factors for rotator cuff tears
• Age • Recurrent overhead activity – Painters – Carpenters – Swimming – Volleyball – Tennis – Weightlifting • Recurrent heavy lifting • OA shoulder with osteophytes • Abnormally-shaped acromion
What are supraspinatus tears?
• 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
What is impingement syndrome?
• 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
What is the painful arc?
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
What is calcification supraspinous tendonitis?
• 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
Describe the pathology of calcification supraspinatus tendonitis?
• 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
What is adhesive capsulitis?
“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
What are the risk factors of adhesive capsulitis?
• 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
Describe the treatment o frozen shoulder?
- 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
What is osteoarthritis of the shoulder?
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Give a treatment overview for
(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)
