Shoulder conditions Flashcards
When do fractures of the scapula occur and how common is it?
Is fixation required?
Relatively uncommon (leads to chest trauma)
Cases: high speed road collisions, crushing injuries, high-impact sports
Fixation: not required because the tone of the surrounding muscles holds the fragments in place while healing occurs
What are the key neurovascular structures at risk when fracture of the surgical neck of the humerus occurs
Axillary nerve (paralysis of deltoid & teres major
Posterior circumflex artery
Why is anterior shoulder dislocation more common than posterior dislocation
-The glenoid fossa is shallow
-The joint is weak at its inferior aspect so the head of the humerus dislocates anteroinferiorly but displaced in anterior due to the pull of the muscles and disruption of the anterior capsule & ligaments
What are the types/causes of anterior shoulder dislocation
-Disruption of the anterior capsule and ligaments
-The head of the humerus may come to lie antero-inferior to the glenoid
What are the mechanisms for anterior shoulder dislocation
-Arm positioned in ABduction & external rotation and pushing it posteriorly (humeral head dislocated antero-inferiorly from the glenoid)
-Direct blow to the posterior shoulder
What causes a Hill-Sachs lesion and what risk does it increase
When humeral head is dislocated anteriorly, (the tone of the infraspinatus & teres minor muscles means) the posterior aspect of the humeral head becomes jammed against the anterior lip of the glenoid fossa
Risk: secondary osteoarthritis
What causes Bankart lesion/labral tear
The force of the humeral head popping out of the socket
What is Bankart lesion
Part of the glenoid labrum being torn off
(sometimes small pieces of bone)
What groups of people are likely to develop Hill-Sachs lesion
<40 yrs with anterior shoulder dislocation
Ppp. with recurrent dislocation
What is Hill-Sachs lesion
Dent (indentation fracture) in the posterolateral humeral head in anterior shoulder dislcation
Causes of posterior dislocation
Violent muscle contraction due to…
-epileptic seizure
-electrocution of lightning strike
Mechanisms of posterior shoulder dislocation
-Blow to the anterior shoulder
-Arm is flexed across the body and pushed posteriorly
What is the presentation of posterior shoulder dislocation
-Arm internally rotated & ADducted
-Flattening/squaring of the shoulder with a prominent coracoid process
-Can’t be externally rotated
How is posterior shoulder dislocation displayed in X-rays
‘Light bulb’ sign- humeral head is more rounded
Glenohumeral distance is increased
(Both anterior&posterior) Scapular/ Y view: head of the humerus should be directly in line with the glenoid fossa (e.g. bifurcation of the Y)
Injuries associated with posterior dislocation
Fractures
Rotator cuff tears
Hill-Sach lesions
Causes of inferior dislocatiton
Hyperabducting the arm: causes humeral head to displace from the inferior aspect of glenoid
Injuries associated with inferior dislocation
Damage to nerves
Rotator cuff tears
Injury to BV
Most common complication of shoulder dislocation and its cause
Recurrent dislocation: damage to the stabilising tissues surrounding the shoulder
Common complications of shoulder dislocation and its causes
Recurrent dislocation
Damage to nerves (axillary, cord of brachial plexus/musculo.)
Damage to the axillary artery (older pop. , less elastic)
What does the axillary nerve supply
Deltoid muscle
Skin overlying the insertion of deltoid (Hilton’s law)
What is HIlton’s law
The nerve supplying the muscle also supplies the skin overlying the insertion of the muscle
In deltoid muscle, this area is called ‘regimental badge area’
What bones are commonly affected in fractures
Head / greater tubercle of humerus
Clavicle
Acromion
What is a rotator cuff muscle tear
A tear of one or more of the tendons of the four rotator cuff muscles of the shoulder
At what site is clavicle fracture most common
Middle third of clavicle
Causes and treatments of clavicle fractures
Causes: fall onto the affected shoulder/onto the outstretched hand
Treatments: Sling (without surgery)
Surgery is required for…
-Bone ends are not in apposition &can’t unite (Complete displacement)
-Tenting of the skin with risk of puncture
(Severe displacement)
-Open fractures
-Neurovascular compromise
-Fractures with interposed muscle
-Floating shoulder (clavicle fracture with ipsilateral fracture of glenoid neck)
What will happen to the position of the arm & clavicular fragments in a displaced midclavicular fracture
Sternocleiodomastoid muscle: Elevates medial segment
Trapezius muscle: Unable to hold the lateral segment
Pectoralis major: Arm is pulled medially
Complications of clavicle fractures
Local complication: Pneumothorax/injury to surrounding neurovascular structure
(i.e.suprascapular nerve- elevation of the medial part of the fracture,
supraclavicular nerve- paraesthesia over the upper chest anteriorly)
-Non-union
-Malunion (uniting in a suboptimal position)-
Causes of rotator cuff tears
Age-related degeneration (blood supply)
What is the principal theory of degenerative-microtrauma model in rotator cuff tears
Age-related tendon degeneration compounded by chronic microtrauma results in…
-partial tendon tears → full rotator cuff tears → inflammatory cells are recruited & oxidative stress →tenocyte apoptosis→’vicious circle’ is created
Risk factors of rotator cuff tears
Recurrent lifting and repetitive overhead activity
Most common clinical presentation of rotator cuff tear
Anterolateral shoulder pain, radiating down the arm
-at rest
-shoulder activity above the horizontal position
(shoulder extension, leaning on an armrest)
Clinical presentation of rotator cuff tear
Weakness of shoulder abduction
Treatment rotator cuff tear
Conservative: rest, analgesia
What is impingement syndrome
Supraspinatus tendon impinges on the coracoacromial arch, leading to irritation and inflammation
Mechanisms & Symptoms of impingement syndrome
Narrowing of the space between the head of humerus and the coracoacromial arch
Symptoms:
-Pain & weakness and reduced range of motion
-Pain during shoulder overhead movement
-Pain when lying on the affected shoulder
Most common type of impingement syndrome
Impingement of supraspinatus tendon under the acromion during abduction of shoulder
-painful arc (60-120°)
Causes of impingement syndrome
-Thickening of the coracoacromial ligament
-Inflammation of the supraspinatus tendon
-Subacromial osteophytes
What is Calcific supraspinatus tendinopathy
Deposits of hydroxyapatite in the tendon of spuraspinatus
Symptoms of Calcific supraspinatus tendinopathy
Acute/chronic pain when…
-abducting/flexing the arm above the level of shoulder
-lying on the shoulder
-stiffness, snapping sensation, reduced range of movement of shoulder (Mechanical symptoms)
-Causes most pain when calcific deposits are reabsorbed by phagocytes
Causes of calcific tendinopathy
- Regional hypoxia: Tenocytes being transformed into chondrocytes and laying down cartilage → Calcium deposits are formed via process resembling endochondral
- Ectopic bone formation from metaplasia of mesenchymal stem cells normally present in tendons
How does Calcific supraspinatus tendinopathy appear on X-rays
Toothpaste, cloudy
-calcific deposits are reabsorbed by phagocytes
Treatment of Calcific supraspinatus tendinopathy
Rest and analgesia
What is Adhesive capsulitis
Capsule of the glenohumeral joint becomes inflamed and stiff
Symptoms of Adhesive capsulitis
Pain is
-constant
-worse at night
-exacerbated by movement & cold weather
Risk factors of Adhesive capsulitis
Female
Epilepsy
Diabetes mellitus
Trauma to shoulder
Connective tissue disorder
Thyroid disease
CVD
Chronic lung disease
Breast cancer
Polymyalgia rheumatica
Parkinson’s disease
Long periods of inactivity
Treatments of Adhesive capsulitis
Physiotherapy
Analgesia
Anti-inflammatory medication
Manipulation under anaesthesia
Resolves with time but other shoulder becomes affected
