By Dr Brendon Aubrey – Sport and Exercise Medicine Registrar
One of the most common presentations in Sport and Exercise Medicine is the patient with shoulder pain. This is because shoulder pain affects people of all ages and activity levels, from elite athletes to sedentary individuals. Presentations vary from acute trauma to repetitive, overuse injuries, and everything in-between.
Treatment success can often hinge on making the correct diagnosis in a timely manner, thus ensuring we are providing appropriate management in the first place. Treatment for one condition in the shoulder will sometimes not benefit other conditions, and in some cases may even exacerbate the problem.Making the correct diagnosis can often be done with history and examination alone, however sometimes it is necessary to investigate patients through imaging. The treating clinician must have a good understanding of what investigations to order, and also be able to interpret the results and apply these to their patient.
Provide Useful Information on the Request Form
Clinicians must remember that the reporting Radiologist does not routinely take a history or examine the patient that has been referred for imaging. Simply writing “shoulder pain” makes the job for the reporting Radiologist significantly harder, and can lead to subtle but critical information being missed or reported incorrectly.
When writing a request the clinician does not need to write a lengthy story, but providing key pieces of information such as the mechanism of injury, positive clinical examination findings, and provisional diagnosis can make all the difference for an accurate report from the Radiologist.
Learn to Interpret the Images Yourself
Occasionally things can be overlooked or underappreciated on imaging reports, and this is likely due to the Radiologist often having no contact with the patient and therefore not being able to correlate clinical and radiological findings. The astute clinician should be able to look at the images themselves and determine the relevant pathology. This way, it becomes very unlikely that important findings get missed.
If the clinician has concerns for pathology that has not received attention in the imaging report, then they should be comfortable speaking with the Radiologist to clarify their findings.
Be Prepared for Incidental Findings
Majority of people over the age of 70 will have asymptomatic, full thickness rotator cuff tears. The clinician must be able to recognise this fact and explain this to the patient, especially if your clinical suspicion does not fit with rotator cuff pathology.
Many other incidental findings can exist in the shoulder, such a calcifications, degenerative changes (especially the AC joint), and bursitis. Stick to your provisional diagnosis, and don’t pay too much attention to the incidental findings if the clinical picture doesn’t fit.
Xray (ANY pathology requiring investigation should include an Xray)
Regardless of the provisional diagnosis, or whether you plan to order an ultrasound or MRI, a plain Xray of the shoulder is a must. Whilst majority of the time an Xray may not be vital to making a diagnosis, simple information regarding bony morphology seen on Xray can avoid the need for a diagnostic MRI, and in some cases be critical to determining the success of non-surgical management.
Ultrasound (Rotator Cuff, subacromial impingement/bursitis, calcific tendinopathy)
Ultrasound provides information for superficial soft tissue and bony changes, as well as having the advantage of recording dynamic pathology such as bursal impingement during shoulder abduction. It is an excellent first line investigation in combination with an Xray if the clinician is investigating rotator cuff pathology.
Whilst MRI is certainly more accurate in detecting more subtle rotator cuff pathology, in a good sonographers hands ultrasound is still the first line investigation for most rotator cuff problems. In cases of acute traumatic rotator cuff pathology, or concerns of a symptomatic full thickness tear (especially in young patients), MRI is recommended due to the potential need for early surgical intervention in which case an accurate diagnosis is essential.
Don’t forget the Xray.
MRI (Instability/labral pathology, acute rotator cuff tear, conditions that have failed to improve)
When it comes to pathology involving the intra-articular structures of the shoulder, this requires MRI to accurately make the diagnosis. MRI is also more accurate than ultrasound at diagnosing more subtle rotator cuff tendinopathy as mentioned earlier. Another common reason to consider MRI is in the patient who is failing to improve despite other previous imaging or treatment. For example, when dealing with a patient with tendinopathy or a small partial thickness tear of the rotator cuff on ultrasound who does not show clinical improvement with standard treatment, the clinician must consider if there is more significant pathology that has not been detected within the limits of the ultrasound.
Over the years there has been debate on the accuracy of MRI with or without contrast injection. Essentially, a 3 Tesla machine does not require a contrast injection to provide accurate images, though in Townsville this is a non-rebateable machine and will incur an out-of-pocket expense to the patient. The alternative is a contrast MRI (MRA) with a 1.5 Tesla machine which can be bulk billed with a Specialist referral, though incurs the slight discomfort and small risk associated with an injection.
Don’t forget the Xray.
CT Scan (Fracture, other bony lesions)
CT scan is rarely performed in the shoulder. It is more common for Orthopaedic surgeons to require a CT for surgical planning purposes. Sometimes a CT can be useful in the setting of trauma and suspected fracture, particularly if an Xray appears normal. CT can also be useful when there is suspicion of a bone lesion that requires further differentiation.
Always start with an Xray before considering a CT scan.