Conditions Of The Shoulder Flashcards
What is a fracture of the surgical neck of the humerus usually from? 1️⃣
- blunt trauma to shoulder
- FOOSH
What key neurovascular structures are at risk?1️⃣
- axillary nerve
- posterior humeral circumflex artery
What will axillary nerve damage result in? 1️⃣
- paralysis of deltoid and teres minor muscles
- difficultly performing abduction of the affected limb
Nerve also innervates skin over deltoid insertion so sensation in this region will be impaired
Where may the long head of the biceps brachii rupture? 2️⃣
Near to its scapular origin
Most common,y I’m patients >50, following quite minimal trauma
In weightlifters, the distal tendon of the biceps sometimes snaps near to its insertion instead
What is a characteristic sign of a ruptured biceps tendon? 2️⃣
‘Popeye sign’
Flexion of the arm at elbow produces a firm lump in the lower part of the arm - this is the unopposed contracted muscle belly of the biceps
What does the patient typically experience?2️⃣
-hear something %’snap’ in the shoulder whilst lifting
-not notice much weakness in the upper limb because the action of the brachialis (flexion) and supinate (supination) muscles is intact
(So management is mainly conservative)
How do dislocated shoulders typically look? 3️⃣
- visibly deformed
- may be visible swelling &/or bruising around shoulder
- restricted movement of shoulder
Why are 90-95% of shoulder dislocations anterior? 3️⃣
- glenoid fossa is shallow
- joint strengthened on its superior, anterior and posterior aspects but weak at its inferior aspect
- head of humerus therefore usually dislocated anteroinferiorly, but then often displaces in an anterior direction (subcoracoid location =60% cases) due to pull of muscles and disruption of the anterior capsule and ligaments
-alternatively, head of humerus may come to lie antero-inferior to the to the glenoid (subglenoid location = 30% cases)
Describe the position of the arm in an anterior shoulder dislocation 3️⃣
- externally rotated
- slightly abducted
Describe the mechanism of the anterior dislocation of the shoulder 3️⃣
- arm abducted and externally rotated e.g. ‘hand behind head’
- unexpected small injury forces arm a little further posteriorly
- shoulder pushed into an extreme position, such that the humeral head dislocates antero-inferiorly from the glenoid
An alternative mechanism is a direct blow to the posterior shoulder
What is a Bankart lesion or labral tear? 3️⃣
Partial tear of the glenoid labrum off the glenoid cavity
Caused by the force of the humeral head popping out of the socket
Sometimes a small piece of bone can be torn off with it
What is a Hill-Sachs lesion and what causes it? 3️⃣
-a dent (indentation fracture) in the posterolateral humeral head
Cause:
-when humeral head dislocated anteriorly, the tone of the infraspinatus and teres minor mean that the posterior aspect of the humeral head becomes jammed against the anterior lip of the glenoid fossa
*increase chance of secondary osteoarthritis in the shoulder joint
When are Hill-Sachs lesions seen? 3️⃣
50% of anterior shoulder dislocations in <40yr olds
80% of recurrent dislocations
Why do posterior shoulder dislocations tend to occur? 3️⃣
When there are violent muscle contractions
- epileptic seizure
- electrocution
- lightning strike
When there is a blow to the anterior shoulder
When arm is flexed across body and pushed posteriorly
How do patients with posterior shoulder dislocations present? 3️⃣
- arm internally rotated and adducted
- demonstrate flattening/squaring of shoulder with a prominent coracoid process
- arm cannot be externally rotated into the anatomical position
How does a posterior shoulder dislocation look on an X-ray? 3️⃣
- can be easily missed as it looks ‘in joint’
- since arm is internally rotated, the projection of the humeral head on the X-ray film changes to a more rounded shape: the ‘lightbulb’ sign
- glenohumeral distance is also increased
What view is also useful for detecting shoulder dislocations on an X-ray? 3️⃣
- scapular or ‘Y’ view
- head of humerus should be directly in line with the glenoid fossa i.e at the bifurcation of the Y
What injuries are commonly associated with posterior shoulder dislocations? 3️⃣
- fractures
- rotator cuff tears
- Hill-sachs lesion
How do inferior dislocations of the shoulder occur? 3️⃣
(Head of humerus sits inferior to the glenoid)
-mechanism is forceful traction on the arm when it is fully extended over the head, as may occur when grasping an object above the head to break a fall e.g. hyperabduction injury
What injuries are associated with an inferior shoulder dislocation? 3️⃣
- damage to nerves
- rotator cuff tears
- injury to blood vessels
What is the most common complication of shoulder dislocation? 3️⃣
-recurrent dislocation
Due to damage to the stabilising tissues surrounding the shoulder
- chance of further dislocation depends on age and activity levels
- each dislocation results in further damage to humeral head and glenoid, therefore increasing the risK of osteoarthritis
Which patients are more likely to have axillary artery damage as a result of shoulder dislocation? 3️⃣
Older age groups
Since their blood vessels are less elastic
May also have a haematoma, absent pulses &/or a cool limb
What nerve injury is common in shoulder dislocations? 3️⃣
Axillary nerve injury
-wraps around humeral neck and supplies deltoid muscles and skin overlying deltoid insertion (regimental badge area)
- full recovery usually made as symptoms resolved when shoulder reduced
- less commonly, should dislocation may damage the cord of the brachial plexus or musculocutaneous nerve
When do significant fractures occur due to shoulder dislocations? 3️⃣
- when there is a traumatic mechanism of injury
- first time dislocation
- person >40 years old
What bones are commonly affected in a significant fracture due to shoulder dislocations? 3️⃣
- humeral head
- greater tubercle of humerus
- clavicle
- acromion
Who do clavicle fractures more commonly occur in? 4️⃣
Children and young adults
What is the function of the clavicle? 4️⃣
- acts as a strut to brace the shoulder from the trunk so the arm has freedom of motion
- transmits force from UL to axial Skelton
- provides protection to brachial plexus, subclavian vessels and apex of the lungs
Where do most clavicle fractures occur? 4️⃣
Middle third of the clavicle (mid-clavicular fracture)
What do most fractures of the clavicle result from? 4️⃣
Falls onto
- the affected shoulder
- an outstretched hand
How are clavicle fractures treated? 4️⃣
- mostly conservatively e.g usual a sling
- sometimes surgically
What are some indications that a fractured clavicle requires surgical fixation? 4️⃣
- complete displacement. (Bone ends not in apposition and cannot unite)
- severe displacement, causes tenting of the skin, with the risk of puncture
- open fracture
- 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 and clavicular fragments in a displaced mid-clavicular fracture?4️⃣
- sternocleiodomastoid muscle elevates the medial segment
- trapezius is unable to hold the lateral segment up against the weight of the upper limb so shoulder drops
- arm pulled medically by pectoralis major (adduction)
What complications may occur due to a displaced mid-clavicular fracture? 4️⃣
-non union
-malunion
-pneumothorax
-injury to surrounding neurovasculature
E.g. damage to suprascapular nerve or supraclavicular nerve
What is a rotator cuff tear? 5️⃣
Tear of one or more tendons of the 4 rotator cuff muscles of the shoulder (supraspinatus, infraspinatus, subscapularis and teres minor)
What are the rotator cuff muscles responsible for? 5️⃣
- stabilising glenohumeral joint
- abducting humerus
- externally rotating humerus
- internally rotating humerus
Which of the rotator cuff tendons is torn most frequently? 5️⃣
-supraspinatus
Affected where it passes beneath the coracoacromial arch, tearing at the site of its insertion into the greater tubercle of the humerus
What do acute and chronic rotator cuff tears occur due to? 5️⃣
- Acute tears e.g following shoulder dislocations
- chronic tears are more common and result from extended use in combination with other factors such as poor biomechanics or muscular imbalance
What is the most common cause of chronic tears of the rotator cuff tendons 5️⃣
Age related degeneration
-with age, blood supply to rotator cuff tendon decreases, impairing the body’s ability to repair minor injuries
Describe the degenerative-microtrauma model 5️⃣
- supposes that age-related tendon degeneration, compounded by chronic microtrauma, results in partial tendon tears that then develop into full rotator cuff tears
- inflammatory cells are recruited and oxidative stress leads to tenocyte (tendon cell) apoptosis, leading to further degeneration
What are some risk factors of rotator cuff tears? 5️⃣
- recurrent lifting and repetitive overhead activity e.g. in carpenters and painters
- sports that involve repeated overhead motion e.g swimming, volleyball, tennis, weightlifting
Describe the most common clinical presentation of rotator cuff tears 5️⃣
-anterolateral shoulder pain, often radiating down the arm
May occur with shoulder activity or present at rest
- pain in shoulder when they lean on their elbow and push downwards as this pushes head of humerus superiorly and decreases space between the head and coracoacromial arch
- pain in shoulder when reaching forwards (flexing shoulder)
- pain restricted movement above the horizontal position as well weakness of shoulder abduction (often only found during physical examination)
When does impingement syndrome occur? 6️⃣
When supraspinatus tendon impinges on the coracoacromial arch, leading to irritation and inflammation
What may cause impingement? 6️⃣
-anything that narrows the space between the humeral head and coracoacromial arch
E.g.
- thickening of the coracoacromial ligament
- inflammation of the supraspinatus tendon
- subacromial osteophytes ( in OA)
When are the symptoms of impingement syndrome felt? 6️⃣
-when shoulder abducted or flexed (since space becomes narrowed)
Symptoms of pain, weakness, reduced range of motion also can include grinding or popping sensation during shoulder movement
-pain often worsened by shoulder overhead movement and also when lying on the affected shoulder
What may the onset of pain in impingement syndrome be? 6️⃣
- acute if it is due to an injury
- insidious (gradually increasing) if it is due to a gradual process such as osteophyte formation
Describe the pain that is felt in impingement syndrome 6️⃣
- dull rather than sharp
- lingers for long period of time
What is the most common form of impingement syndrome? 6️⃣
- impingement of the supraspinatus tendon under the acromion during shoulder abduction
- creates a ‘painful arc’ between 60 and 120 degrees of abduction (below 60 and above 120 degrees, patients experience significantly less or no pain)
What do patients with impingement of the supraspinatus tendon often report?6️⃣
-pain on reaching upwards to brush hair or to lift something from an overhead shelf
What is calcific supraspinatus tendinopathy characterised by? 7️⃣
Characterised by presence of macroscopic deposits of hydroxyapatite in the tendon of the supraspinatus
(Can occur in tendon of any rotator cuff but most commonly occurs in supraspinatus)
How does calcific supraspinatus tendinopathy present? 7️⃣
- acute or chronic pain, often aggravated by shoulder abduction or flexion above level of the shoulder or by lying on affected shoulder
- mechanical symptoms may occur due to physical presence of a large deposit, leading to stiffness, snapping sensation, catching or reduced range of movement of the shoulder
Describe 2 theories of how calcific tendinopathy arises 7️⃣
- regional hypoxia leads to tenocytes being transformed into chondrocytes and laying down cartilage in the tendon
- calcium deposits are then formed through a process resembling endochondral ossification
-ectopic bone formation from metaplasia of mesenchymal stem cells normally present in tendons into osteogenic cells
Describe the calcific deposits 7️⃣
- visible on x-ray
- crystalline in their ‘resting phase’
- eventually reabsorbed by phagocytes, and it is during this reabsorption stage that they tend to cause the most pain
- during reabsorption, they look macroscopically like ‘toothpaste’ and often appear ‘cloudy’ (less well defined) on X-ray
How is calcific supraspinatus tendinopathy treated? 7️⃣
- initially conservatively with rest and analgesia
- surgical treatment sometime required for persistent symptoms
What is adhesive capsulitis (‘frozen shoulder’)? 8️⃣
-a painful and disabling disorder in which the capsule of the glenohumeral joint becomes inflamed and stiff, greatly restricting movement and causing chronic pain
Describe the pain felt due to adhesive capsulitis 8️⃣
Usually constant, worse at night and exacerbated by movement and cold weather
What are some risk factors of adhesive capsulitis? 8️⃣
- female gender
- epilepsy with tonic seizures
- diabetes mellitus
- trauma to shoulder
- connective tissue disease
- breast cancer
- polymyalgia rheumatica
- Parkinson’s disease
- long periods of inactivity e.g from injury or stroke or illness
What do patients with adhesive capsulitis often experience? 8️⃣
- severe pain
- sleep deprivation for prolonged periods
Resulting in severe interference with work and activities of daily living
*some develop depression as a result
Describe the treatment for adhesive capsulitis 8️⃣
- physiotherapy
- analgesia and anti-inflammatory medication
- manipulation under anaesthesia which breaks up the adhesions and scar tissue in the joint to help restore range of motion
- intense post-operative physiotherapy then helps to maintain the movement that has been gained
- typically resolved with time and most patients ultimately regain 90% of shoulder motion
What does OA of the shoulder usually affect? 9️⃣
- people >50
- acromioclavicular joint rather than the glenohumeral joint
How is OA of the shoulder treated? 9️⃣
- activity modification, analgesia and NSAIDs, nutritional supplement
- steroid injections into the joint to reduce swelling and thereby alleviate stiffness and pain
- hyaluronic acid injection into the joint may increase lubrications
- arthroscopy to remove loose pieces of damage cartilage from the glenohumeral joint
- hemiarthroplasty : replacement of humeral head
- total shoulder replacement (replacement of humeral head and glenoid)
