Up to a third of people worldwide have shoulder pain; it’s one of the most common musculoskeletal complaints. But medical imaging might not reveal the problem—in fact, it could even cloud it.
In a study published in JAMA Internal Medicine this week, 99 percent of adults over 40 were found to have at least one abnormality in a rotator cuff on magnetic resonance imaging (MRI). The rotator cuff is the group of muscles and tendons in a shoulder joint that keeps the upper arm bone securely in the shoulder socket—and is often blamed for pain and other symptoms. The trouble is, the vast majority of the people in the study had no problems with their shoulders.
The finding calls into question the growing use of MRIs to try to diagnose shoulder pain—and, in turn, the growing problem of overtreatment of rotator cuff (RC) abnormalities, which includes partial- and full-thickness tears as well as signs of tendinopathy (tendon swelling and thickening).
“While we cannot dismiss the possibility that some RC tears may contribute to shoulder symptoms, our findings indicate that we are currently unable to distinguish clinically meaningful MRI abnormalities from incidental findings,” the study authors concluded.
The study was carried out by Finnish researchers, who tapped into a nationally representative sample of adults who had signed up for a public health survey. In the end, 602 participants, aged 41 to 76, completed the study, which included answering questions about shoulder pain and getting MRIs on both shoulders. Of the 602 participants, 492 (82 percent) reported no shoulder symptoms, while 110 (18 percent) did report symptoms.
The MRI revealed that 595 of them (99 percent) had at least one RC abnormality. The most common abnormality was a partial-thickness tear (62 percent), followed by tendinopathy (25 percent), and a full-thickness tear (11 percent). The prevalence of abnormalities was similar between males and females. But the abnormalities showed a clear age-related progression, with no full-thickness tears in participants under 45 and the greatest proportion in people 70 to 76.