Ubiquitous Abnormalities: Why 99% of Shoulders Over 40 are "Normal" on an MRI

Hook

Medical imaging might not be revealing the problem—in fact, for millions of people over the age of 40, an MRI could be clouding the truth about their health.

What Happened

A study published in JAMA Internal Medicine found that 99 percent of adults over 40 have at least one abnormality in their rotator cuff on an MRI. Most notably, the vast majority of participants—82 percent—reported no shoulder symptoms whatsoever. The study, conducted by Finnish researchers, examined 602 participants and found that asymptomatic and symptomatic groups showed nearly identical rates of partial-thickness tears and tendinopathy.

Context

The findings suggest that these "abnormalities" are actually ubiquitous—and therefore normal—age-related changes rather than structural injuries that require repair. Clinicians are now being urged to rethink the language they use with patients, shifting away from "value-laden" terms like "tear" and "abnormality" toward more precise descriptions like "fraying," "structural alteration," or "degeneration".

Impact

This shift aims to reduce patient anxiety and the perceived need for surgery. Orthopedic surgeons from UCSF agree that for pain not related to a specific injury, clinicians should first attempt several months of physical therapy or "watch-and-wait" before ordering an MRI.

Insight

The study highlights a growing problem in modern medicine: overtreatment. Because we are currently unable to distinguish "clinically meaningful" findings from incidental ones, treatment decisions should be guided by a patient’s functional limitations and history rather than just what is seen on a screen.

Takeaway

If you are over 40 and get a shoulder MRI, there is a 99% chance it will show a "defect." Understanding that this is a normal part of aging, not a requirement for surgery, is the key to better health outcomes and lower medical costs.