When musculoskeletal ultrasound adds information beyond MRI

In rotator cuff injuries and other dynamic pathologies, ultrasound can add relevant diagnostic information to the orthopedic surgeon's decision — even when MRI has already been performed.

It's tempting to treat ultrasound and MRI as competitors in musculoskeletal assessment. In practice, they're complementary — and in certain specific situations, ultrasound adds information that a standalone, static MRI does not provide.

Where ultrasound's accuracy approaches — or exceeds

For full-thickness rotator cuff tears, meta-analyses show ultrasound accuracy comparable to conventional MRI, with high sensitivity — especially for the supraspinatus tendon. MR arthrography remains superior for partial tears and detailed surgical planning.

The information only a dynamic exam provides

Ultrasound's real differentiator isn't static resolution, it's dynamic assessment: watching the tendon during active movement allows documentation of subacromial impingement and instability that an MRI — performed with the patient still — simply cannot capture. For the orthopedic surgeon deciding between conservative and surgical management, this functional information can weigh as much as the structural image.