Why after 40, almost everyone gets shoulder problems on MRIs

Shoulder pain is one of the most common reasons for visits to the doctor.

It's often associated with the rotator cuff, a set of four muscles and tendons that hold the humerus together and help lift and rotate the arm. But a new study shows: on MRI scans, rotator cuff "abnormalities" after age 40 are found in almost everyone - even those with no pain.

This conclusion was made by the authors of the Finnish population-based study FIMAGE, published in JAMA Internal Medicine.

Researchers randomly selected 602 adults aged 41-76 from a national database (i.e. not just people who went to the doctor because of pain). The participants filled out a questionnaire about shoulder pain and limitations, and then all underwent MRI scans of both shoulders on a 3 Tesla machine. Radiologists evaluated the scans "blind" - without knowing whether the person had pain or not.

The results were impressive: 99% of the participants had at least one rotator cuff change on MRI. And such findings were almost equally frequent in people without symptoms and in those who complained of pain: changes were found in 96% of "without pain" and in 98% of "with pain".

This means a simple thing: the mere fact of "changes" on MRI often reflects normal age-related tendon changes, not necessarily the cause of the pain. The authors warn that routine MRI should not be used as the sole basis for diagnosis and treatment of "non-traumatic" shoulder pain - otherwise there is a risk of treating the scan rather than the person.