Differentials
Posterior glenohumeral dislocation
SIGNS / SYMPTOMS
Posterior shoulder dislocations usually occur after a traumatic event and are also traditionally attributed to electrocution or seizure.
Acute onset of pain and immediate severe loss of motion help differentiate from adhesive capsulitis.
INVESTIGATIONS
Axillary view plain radiograph will show a posterior shoulder dislocation.
Rotator cuff injury
SIGNS / SYMPTOMS
Pain associated with decreased range of motion is common. Pain is typically aggravated by overhead activities.
Decreased active range of motion on physical examination, but should have normal or near-normal passive range of motion.
Pain and weakness on affected side elicited with provocative manoeuvres.
INVESTIGATIONS
Shoulder MRI will show evidence of rotator cuff tear.
Subacromial rotator cuff impingement
SIGNS / SYMPTOMS
Typically causes pain with shoulder elevation between 60° and 120° due to the rotator cuff tendons compressing against the anterior acromion and coracoacromial ligament (painful arc syndrome).
There may be weakness due to pain.
INVESTIGATIONS
Shoulder MRI may show evidence of inflammation in the subacromial space.
Proximal biceps tendonitis
SIGNS / SYMPTOMS
Tenderness at bicipital groove.
Pain in the anterior region of the shoulder with Speed test (resisted forward arm flexion with the elbow extended) or Yergason test (resisted forward supination).
INVESTIGATIONS
MRI may reveal a subluxated long head of the biceps tendon, or demonstrate degeneration within the proximal biceps tendon.
Superior labral tears
SIGNS / SYMPTOMS
Pain and decreased range of motion is common.
Weakness is not a presenting symptom.
Pain elicited with active compression test (resisted arm elevation with the arm 15° adducted, forward flexed parallel with the floor and maximal pronation).
INVESTIGATIONS
MRI or MR arthrograms demonstrate superior glenoid labral tears.
Acromioclavicular joint arthrosis
SIGNS / SYMPTOMS
Anterior shoulder pain.
Usually have pain with cross arm adduction, and no limitation of passive range of motion.
INVESTIGATIONS
Either plain film radiographs or MRI will demonstrate degeneration of the acromioclavicular joint, distal clavicle osteolysis, and cystic formation at the end of the clavicle.
Although features suggestive of acromioclavicular joint arthrosis may be present on imaging, clinical examination can be normal.
Cervical spine neuropathy or myelopathy/Degenerative cervical spine disease
SIGNS / SYMPTOMS
Shoulder pain and decreased motion due to cervical spine pathology is usually accompanied by neck pain and/or radiating pain, numbness, or paraesthesias down the arm. Weakness or difficulty with fine motor skills involving the hand may also be reported.
Full sensory, motor, and reflex examinations as well as cervical spine examination will usually manifest symptoms and signs outside the shoulder.
Positive Spurling manoeuvre (one hand is placed on top of the patient's head while stabilising the shoulders, the neck is then hyperextended and the head gently tilted towards the symptomatic site).
INVESTIGATIONS
Plain film radiographs may demonstrate degenerative changes in the cervical spine as well as vertebral body subluxation.
MRI of the spine may confirm the radiographic findings and show evidence of cervical nerve root compression.
Glenohumeral arthritis
SIGNS / SYMPTOMS
Glenohumeral arthritis often presents with restricted range of motion and pain. Patients may note a sensation of “popping” or crepitus.
INVESTIGATIONS
Plain radiographs of the shoulder will demonstrate decreased joint space and marginal osteophytes. Often an AP radiograph of the shoulder will demonstrate an osteophyte at the inferior articular margin of the humeral head that is diagnostic of osteoarthritis.
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