Rotator Cuff Tear Flashcards
What is the rotator cuff?
The rotator cuff is a group of 4 muscles that support and rotate the glenohumeral joint.
How common are rotator cuff tears?
Rotator cuff tears are common; acute full thickness tears have an incidence around 2.5 per 10,000 patients for those aged 40-70, whilst the prevalence of a rotator cuff tear in the general population is around 20%.
Briefly describe the anatomy of the rotator cuff
The rotator cuff is composed of four muscles:
- Supraspinatus: abduction
- Infraspinatus: external rotation
- Teres minor: external rotation
- Subscapularis: internal rotation
Alongside their role in movement of the shoulder, these muscles act to stabilise the humeral head in the glenoid fossa, playing a key role in maintaining overall shoulder stability.
Briefly describe the classification of rotator cuff tears
Rotator cuff tears are classified as either acute (lasting <3 months) or chronic (lasting >3 months) tears. They can be either partial thickness or full thickness tears.
Full thickness tears can be further classified into small (<1cm), medium (1-3cm), large (3-5cm), or massive (>5cm or involves multiple tendons) tears.
Briefly describe the pathophysiology of rotator cuff tears
Note: both acute and chronic
Acute tears commonly occur within tendons with pre-existing degeneration, typically occurring alone following minimal force. However, acute tears can occur in young individuals when the force required to cause a tear can be large, therefore often occur alongside other injuries.
Chronic tears occur in individuals with degenerative microtears to the tendon, most commonly from overuse and seen in greater incidence with increasing age.
What are the risk factors for rotator cuff tears?
The main risk factors for rotator cuff tears are:
- Age
- Trauma
- Overuse
- Repetitive overhead shoulder motions (e.g. athletes, certain occupations)
- BMI>25
- Smoking
- Diabetes mellitus
What are the clincial features of a rotator cuff tear?
Patients will present with pain over the lateral aspect of shoulder and an inability to abduct the arm above 90 degrees. Tears are more common in the dominant arm.
On examination, there is often tenderness over the greater tuberosity and subacromial bursa regions. Supraspinatus and infraspinatus atrophy can be seen in massive rotator cuff tears.
What tests can be used to assess rotator cuff tears?
- Jobe’s test
- Gerber’s lift-off test
- Posterior cuff test
Briefly describe Jobe’s test
The ‘empty can test’; tests supraspinatus
Place the shoulder in 90° abduction and 30° of forward flexion and internally rotate fully (as if you’re ‘emptying a can’) and gently push downwards on the arm.
A positive test is present if there is weakness on resistance.
Briefly describe Gerber’s lift off test
Tests subscapularis.
Internally rotate the arm so the dorsal surface of hand rests on lower back. Ask the patient to lift hand away from back against examiner resistance.
A positive test is weakness in actively lifting the hand away from back (compare to the contralateral side).
Briefly describe posterior cuff test
Tests infraspinatus and teres minor.
The arm positioned at patient’s side, with the elbow flexed to 90°. The patient is instructed to externally rotate their arm against resistance.
A positive test is present if there is weakness on resistance.
What investigations should be ordered for a rotator cuff tear?
Patients presenting with clinical features of a rotator cuff tear should have an urgent plain film radiograph to exclude a fracture. Most plain film radiographs will be unremarkable.
Once fracture has been excluded, rotator cuff tears can be assessed through further imaging. Ultrasonograhy can establish the presence and size of tear, whilst MRI imaging can also be used to detect the size, characteristics, and location of any tear.
How may a rotator cuff tear present on x-ray?
In chronic tears, there may be evidence of reduced acromiohumeral distance, or sclerosis and cyst formation the rotator cuff insertion on the greater tuberosity of the humerus.
When are conservative measurements preferred in rotator cuff tears?
Conservative management is preferred in patients who are not limited by pain or loss of function, or those who have significant co-morbidities and unsuitable for surgery.
Briefly describe conservative management for rotator cuff tears
Those who are presenting within 2 weeks since injury can be advised for a conservative management approach, including analgesia and physiotherapy with activity modification. Corticosteroid injections into the subacromial space can also be trialled.
