99% of adults over 40 have shoulder “abnormalities” on an MRI, study finds

A significant number of individuals, estimated to be one in three globally, experience shoulder pain, making it one of the most prevalent musculoskeletal issues. However, a recent study published in JAMA Internal Medicine suggests that medical imaging may not always clarify the situation—in fact, it could potentially complicate it. The research found that 99% of adults aged 40 and older exhibited at least one abnormality in their rotator cuff as seen on magnetic resonance imaging (MRI). The rotator cuff, a crucial group of muscles and tendons in the shoulder joint, plays an essential role in keeping the upper arm bone securely in place. It's often implicated in cases of shoulder discomfort and other related issues. Surprisingly, the majority of participants in the study reported no shoulder problems. This finding raises concerns about the increasing reliance on MRIs for diagnosing shoulder pain and highlights the potential for excessive treatment of rotator cuff abnormalities, which can include both partial and full-thickness tears, as well as signs of tendinopathy, characterized by tendon swelling and thickening. The study's authors noted, "While we cannot dismiss the possibility that some rotator cuff tears may contribute to shoulder symptoms, our findings indicate that we are currently unable to differentiate between clinically significant MRI abnormalities and incidental findings." Conducted by Finnish researchers, the study analyzed a nationally representative sample of adults who participated in a public health survey. Out of 602 participants, aged between 41 and 76, 492 (82%) reported no shoulder symptoms, while 110 (18%) did. The MRI results showed that an overwhelming 595 participants (99%) had at least one rotator cuff abnormality. The most frequently observed issue was a partial-thickness tear, found in 62% of cases, followed by tendinopathy in 25%, and full-thickness tears in 11%. Interestingly, the prevalence of these abnormalities did not differ significantly between men and women. However, there was a notable age-related trend, with no full-thickness tears seen in participants younger than 45 and the highest incidence observed in those aged 70 to 76.