Pain is the most common presentation in the shoulder. After 15 years of consultant practice, I would like to share some tips and pearls learnt, sometimes through bitter experience. As the saying goes, ‘Good judgment comes from experience, experience comes from bad judgment.’
To begin, use the anatomic paradigm. We are all taught and use the tried-and-tested approach of history, examination, investigation then coming up with a differential diagnosis. I have found it useful to run an anatomic approach parallel to this – running through the different anatomic structures which may be the pain generator(s) for the patient and think whether the pain relates to:
- the glenohumeral joint (e.g. capsulitis, arthritis)
- the subacromial region (e.g. cuff tear, calcific tendinitis, bursitis)
- the biceps tendon (tears, tendinopathy)
- the acromioclavicular (AC) joint (e.g. arthritis, bone oedema)
- teferred pain from the cervical spine or brachial neuritis
From the opening questions in the history taking, we can ask to follow up focused questions related to the different structures, such as the exact location of the pain (e.g. superior over the AC joint), provoking factors, responses to injections, acuity versus chronicity of the pain, and the presence or not of stiffness.
Instead of performing a generic examination, we then do a focused examination to help confirm or refute our working diagnosis. We can do a slightly different examination for glenohumeral pathology versus the AC joint, versus one for instability etc., considering the nuances of the patient’s presentation.
Start with an X-ray
Many patients are referred with an ultrasound of the shoulder and perhaps a subacromial injection. Radiographs are a safe, efficient and useful tool for aiding in the diagnosis. Stiff and painful shoulder with a normal X-ray? Think frozen shoulder. But one must rule out osteoarthritis. Look out for sclerosis of the greater tuberosity and enthesopathic changes which suggest cuff tears or AC joint arthritis. Calcifications may be present. There may be a high riding humeral head consistent with chronic and extensive cuff tears.
Injecting a shoulder with arthritis or cuff deficiency where a joint replacement might be the end game, could complicate matters with an infection compromising the patient’s treatment. Or worse, one may miss a metastasis or malign problem. It is critical to treat the patient and not the investigation.
Investigations are a useful tool to aid the diagnosis, however, there are some pitfalls to look out for. For example, it is very common in the middle-aged patient and older, that AC joint arthritis is present on the X-ray. This should be confirmed on the history and examination as to whether it is likely to be the patient’s pain generator or not.
One thing I have found useful is to use local anaesthetic injections, only to aid diagnosis. This is a good way of confirming if an anatomic area is the pain generator without the ‘feel good’ effects of the steroid with a diagnostic injection into the structure of interest.
An MRI is a highly sensitive test and will often show multiple pathologies. Our job is to marry these up with the patient’s presentation and separate out age-related changes versus pathology.
There may be multiple pain generators as the shoulder is a complex of joints and soft tissue structures – the biceps, cuff and AC joints can all contribute. This is where a nuanced and careful history, examination and diagnostic injections can help in identifying the precise pain generators.
Watch for frozen shoulder, which is the great mimicker in the shoulder. I’m sure I am not alone in having misdiagnosed a patient’s source of pain as being cuff tears or other pathologies when the underlying cause was an evolving frozen shoulder. Loss of motion can be subtle and only be present a few months after the onset of pain. Always be on the lookout for this condition. Sometimes, observation after ruling out malign causes is the best way to arrive at this diagnosis, where the condition will declare itself.
Key messages
- Pain, the most common presentation in the shoulder, can come from multiple structures
- A systematic, comprehensive and nuanced approach is key
- Investigations, whilst very useful have pitfalls.
Author competing interests – nil