Shoulder injuries

Question 1

what is the most common type of shoulder dislocation?

Answer 1

anterior dislocations (head of humerus sits anterior to glenoid fossa)
in an anterior dislocation the arm is held in a position of external rotation and slight abduction

Question 2

what is a bankart lesion or labra tear?

Answer 2

force of humeral head popping out of socket causes part of glenoid labrum to be torn off
(small piece of bone may also be torn off as well)

Question 3

what is a Hill-Sachs lesion?

Answer 3

when the shoulder is dislocated anteriorly, the posterior aspect of humeral head is jammed against the anterior lip of glenoid fossa
this causes a dent in the posterolateral humeral head (Hill-Sachs lesion)
this increases risk of secondary osteoarthritis

Question 4

what may cause a posterior shoulder dislocation?

Answer 4

strike or large force applied to anterior aspect of shoulder:
- epileptic seizure
- lightning strike
- when arm is flexed (across body) and pushed posteriorly

Question 5

how does a patient with a posterior dislocation present?

Answer 5

• internally rotated and adducted arm
• flattening or squaring of shoulder with prominent coracoid process
• can’t externally rotate into anatomical position

Question 6

what x-ray observations can be seen on a posteriorly dislocated shoulder injury?

Answer 6

humeral head is more rounded (light bulb) because arm is internally rotated
glemoral distance increases

Question 7

what secondary injuries are commonly associated with posterior shoulder dislocations?

Answer 7

fractures
rotator cuff tears
Hill–Sachs lesion

Question 8

what is an inferior shoulder dislocation and what causes it?

Answer 8

in an inferior shoulder dislocation the humeral head sits inferior to glenoid
caused by forceful traction on arm when it is fully extended over head (hyperabduction injury)

Question 9

what are common secondary complication of any shoulder dislocation?

Answer 9

• recurrent dislocation due to damage of stabilising tissues surrounding shoulder
  damage (most common at 60%)
• damage to axillary artery can cause a haematoma, absent pulse or a cool limb (1-2%)
• axillary nerve injury usually recover fully (10-40%)
• fractures usually to head or greater tubercle of humerus, clavicle and acromion are common especially after a traumatic mechanism of injury (25%)
• rotator cuff muscle tear common in inferior dislocations in all groups

Question 10

what is the function of the clavicle?

Answer 10

The clavicle acts as a strut to brace the shoulder from the trunk (so the arm has freedom of motion)
transmits force from the upper limb to the axial skeleton
It also provides protection to the brachial plexus, subclavian vessels and the apex of the lung.

Question 11

what’s the most common type of clavicle fracture and what causes it?

Answer 11

80% of fractures occur in middle third of clavicle
causes: fall onto affected shoulder or on outstretched hands

Question 12

how are clavicle fractures treated?

Answer 12

conservatively (i.e no surgery) with a sling

Question 13

when would a clavicle fracture be treated with surgery?

Answer 13

• Complete displacement (so the bone ends are not in apposition and cannot unite)
• Severe displacement causing tenting of the skin, with the risk of puncture (see below)
• Open fractures (fracture associated with a break in the integrity of skin)
• Neurovascular compromise
• Fractures with interposed muscle
• Floating shoulder: clavicle fracture with ipsilateral fracture of glenoid neck

Question 14

What will happen to the position of the arm and clavicular fragments in a displaced mid-clavicular fracture (fracture at the mid-point of the clavicle)?

Answer 14

The sternocleiodomastoid muscle elevates the medial segment
Because the trapezius muscle is unable to hold the lateral segment up against the weight of the upper limb, the shoulder drops
The arm is pulled medially by pectoralis major (adduction).

Question 15

what are rotator cuff tears?

Answer 15

a tear of one or more of the tendons of the four rotator cuff muscles of the shoulder (supraspinatus, infraspinatus, subscapularis and teres minor)

Question 16

what causes rotator cuff tears?

Answer 16

• acute tears can occur but most rotator cuff tears are chronic, resulting from extended use in combination with other factors
• age related degeneration (blood supply to rotator cuff tendon decreases impairing body’s ability to repair minor injuries)
• recurrent lifting and repetitive overhead activity are also risk factors

Question 17

what is the degenerative-microtrauma model?

Answer 17

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, thus a ‘vicious circle’ is created.

Question 18

how do rotator cuff tears present?

Answer 18

the most common presentation clinically is anterolateral shoulder pain, often radiating down the arm
Patients experience pain in their shoulder when they lean on their elbow and push downwards as this pushes the head of the humerus superiorly and decreases the space between the humeral head and the coracoacromial arch.
They also experience pain in the shoulder when reaching forward
Pain-restricted movement above the horizontal position may be present, as well as weakness of shoulder abduction

Question 19

what is impingement syndrome?

Answer 19

supraspinatus tendon impinges (rubs or catches) on the coraco-acromial arch, leading to irritation and inflammation

Question 20

what causes impingement syndrome?

Answer 20

impingement is caused by anything that decreases space between head of humerus and coracoacromial arch:
- thickening of the coracoacromial ligament
- inflammation of the supraspinatus tendon
- subacromial osteophytes

Question 21

what are the symptoms of impingement syndrome?

Answer 21

when the shoulder is abducted or flexed, the space becomes narrowed further, resulting in symptoms of pain, weakness and reduced range of motion

Question 22

what is the most common type of impingement syndrome?

Answer 22

impingement of supraspinatus tendon under the acromion during abduction of the shoulder
This creates a ‘painful arc’ between 60 and 120 degrees of abduction

Question 23

what is a calcific supraspinatus tendinopathy?

Answer 23

Calcific supraspinatus tendinopathy (historically ‘tendonitis’) is characterised by the presence of macroscopic deposits of hydroxyapatite (a crystalline form of calcium phosphate) in the tendon of supraspinatus

Question 24

how do patients with calcific supraspinatus tendinopathy present?

Answer 24

present with acute or chronic pain, often aggravated by abducting or flexing the arm above the level of the shoulder, or by lying on the shoulder
Mechanical symptoms may also occur due to the physical presence of a large deposit, leading to stiffness, a snapping sensation, catching, or reduced range of movement of the shoulder

Question 25

what can cause calcific tendinopathy?

Answer 25

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 Another theory involves ectopic bone formation from metaplasia of mesenchymal stem cells normally present in tendons into osteogenic cells.

Question 26

how is calcific supraspinatus tendinopathy treated?

Answer 26

initially conservative with rest and analgesia. Surgical treatment is sometimes required for persistent symptoms.

Question 27

what is adhesive capsulitis (“frozen shoulder”)?

Answer 27

a painful and disabling disorder in which the capsule of the glenohumeral joint becomes inflamed and stiff, greatly restricting movement and causing chronic pain

Question 28

what are the risk factors associated with adhesive capsulitis?

Answer 28

Risk factors include
* Female gender
* Epilepsy with tonic seizures (i.e. sudden muscle contractions)
* Diabetes mellitus (the theory is that glucose molecules bond to the capsular
collagen)
* Trauma to the shoulder
* Connective tissue disease
* Thyroid disease (hypo and hyperthyroidism)
* Cardiovascular disease
* Chronic lung disease
* Breast cancer
* Polymyalgia rheumatica (an inflammatory condition causing muscle pain and
weakness)
* Parkinson’s disease
* Long periods of inactivity (from injury, stroke or illness) can precipitate
frozen shoulder, and it can also occur alongside other shoulder problems e.g. calcific tendinopathy or rotator cuff tear.

Question 29

what are the symptoms of adhesive capsulitis?

Answer 29

Patients with frozen shoulder often experience severe pain and sleep deprivation for prolonged periods, resulting in severe interference with their work and activities of daily living. Some develop depression as a result.

Question 30

how is adhesive capsulitis treated?

Answer 30

physiotherapy, analgesia and anti- inflammatory medication.
Patients sometimes undergo 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

Question 31

who does osteoarthritis of shoulder typically affect?

Answer 31

people over 50 years of age and more commonly affects the acromioclavicular joint than the glenohumeral joint

Question 32

what is the treatment of osteoarthritis?

Answer 32

• involves activity modification (avoiding activities that precipitate symptoms), analgesia, and anti-inflammatories (NSAIDs)
• steroid injections into joint to reduce swelling and alleviate stiffness and pain
• Arthroscopy (keyhole surgery) can be performed to remove loose pieces of damaged cartilage from the glenohumeral joint
• some patients will progress to hemiarthroplasty (replacement of the humeral head)
• total shoulder replacement (replacement of the humeral head and the glenoid)