Musculoskeletal investigations - Examining the shoulder joint

Consider the age of the patient when establishing a diagnosis, explain Mr Steve Lipscombe and Dr Dan Bunstone.

Middle-aged patients suffer more from adhesive capsulitis (shown above) and calcific tendonitis (Photograph: SPL)
Middle-aged patients suffer more from adhesive capsulitis (shown above) and calcific tendonitis (Photograph: SPL)

The difficulty with shoulder examinations is the multitude of special tests which can be employed (over 100), and the freedom of movement present within the normal joint. The doctor must determine whether the shoulder movement is limited due to muscle weakness, stiffness (capsulitis and glenohumeral osteoarthritis) or simply pain.

Common conditions
Establishing a diagnosis can be helped greatly by considering the ages at which conditions tend to occur. The examination then becomes one of proving the diagnosis.

In the young patient, instability and hyperlaxity form the majority of problems. The two problems can become blurred, but it is important to appreciate the concept that either the stabilisers of the shoulder have been torn leading to instability or the stabilisers in the shoulder were weak from the outset. Establishing hyperlaxity in other joints such as fingers, wrist and elbow will help confirm hyperlaxity as a diagnosis.

A history of injury followed by the sensation of instability or clicking suggests a tear. If there is documentation of shoulder dislocation, accept this and do not attempt to stress the joint.

Middle-aged patients suffer more from adhesive capsulitis (frozen shoulder) and calcific tendonitis. Their presentations will be similar in the early stages, with severe acute pain at rest exacerbated by most movements.

The absence of trauma is a key factor, but other sinister features suggesting a rare upper limb malignancy or avascular necrosis of the humeral head (more common with alcoholism and prolonged steroid use) need to be excluded. It is important to note that adhesive capsulitis can be bilateral and is more common in diabetic patients.

Older patients typically present with degenerative disorders of the glenohumeral joint and acromioclavicular (AC) joint, or with rotator cuff disease.

Impingement occurs due to reduction in the subacromial space as the humeral head rubs on the under surface of the acromion. It is commonly due to bone spurs, acromial hooks, tendinopathy, or coracoacromial ligament hypertrophy. It is a symptom rather than a diagnosis, occurring at any age.

Proving the diagnosis
Ask the patient to indicate where they feel pain. If they indicate the trapezius, pain here is more commonly a referred neck pain, although point tenderness over a prominent AC joint tends to be the site of symptoms. Shoulder pain is indicated over the deltoid region, although this could also indicate neck problems if pain extends below the elbow.

Muscle wasting observed from along the upper portion of the scapula suggests rotator cuff muscle deficiency. The scapula spine divides the supraand infraspinatus muscles, the commonest sites of cuff tear.

The shoulder movements
There are four main movements to test: forward flexion, abduction, external rotation (elbow at the hip and moving the rotating arm outwards), and internal rotation (hand behind back between the shoulder blades). These movements are best observed stood at the side of the patient.

If pain predominates in all movements consider capsulitis or, in the presence of crepitus and patient age, glenohumeral osteoarthritis.

As the process of capsulitis progresses, pain at rest settles and loss of external rotation becomes the cardinal sign.

If pain occurs with certain movements consider impingement. An abduction-impingement arc can be performed, but the Hawkins-Kennedy test is more useful (maintain shoulder and elbow at 90 degs then rotate hand toward the floor).

The scarf test is accomplished by reaching the hand over the opposite shoulder towards the scapula.

This will aggravate AC joint arthritis, causing localised pain.

With shoulder stiffness, external rotation is again the key movement lost. As already explained, this is commonly due to capsulitis. If stiffness occurs with crepitus and pain, osteoarthritis is the likely culprit.

Weakness is perhaps the trickiest to elicit, especially in the presence of pain.

It is important to recognise that as many as 40 per cent of 'older' patients will have an asymptomatic cuff tear. The tear has occurred slowly allowing the deltoid to compensate the movements. More sudden deterioration, sometimes precipitated by an apparently innocent fall, can lead to dramatic shoulder weakness. Whilst there are four cuff muscles it proves difficult to test teres minor in isolation and it is probably not of any clinical significance.

The remaining muscles of the cuff can be tested with three simple actions: supraspinatus - point thumb down and ask patient to raise arm in front of them; and infraspinatus - resisted external rotation (see below).


External rotation

Subscapularis - press hand into abdomen while keeping elbow forwards (Napoleon test - see below).Weakness in the movements suggests a tear within the cuff at this point.


Napleon Test

Conclusion
The shoulder can be a difficult joint to examine and determine a diagnosis. The process can be aided by considering the age of the patient, and examining the nine shoulder movements discussed above.

This is a brief guide, but will help to differentiate between the most common shoulder presentations.

  • Mr Lipscombe is an orthopaedic registrar in Aintree, and Dr Bunstone is a GP principal in Cheshire
Common conditions
  • Hyperlaxity
  • Muscle tear
  • Dislocation
  • Adhesive capsulitis (frozen shoulder)
  • Calcific tendonitis
  • Osteoarthritis

 

Key points
  • If movement is limited, consider whether this is due to stiffness, pain or muscle weakness.
  • Consider the age of the patient when making a diagnosis.
  • Ask the patient to indicate where they feel pain.
  • Stand at the side of the patient to observe movements.


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