Rotator cuff: signs of tendinopathy on ultrasound

The findings that help distinguish tendinosis, partial tear and full-thickness tear of the rotator cuff — and the most common pitfalls in that assessment.

Rotator cuff tendinopathy is one of the most common reasons for a shoulder ultrasound referral, and the spectrum of findings ranges from mild degenerative change to full-thickness tear — distinguishing between these degrees directly changes clinical management.

Tendinosis

The most common finding is tendon thickening with focal heterogeneity of echotexture, without fiber discontinuity — a degenerative, chronic pattern more associated with overuse than with a single acute event.

Partial-thickness tear

A focal discontinuity of fibers, usually on the articular or bursal surface of the tendon, without significant retraction, characterizes a partial tear. Measuring the thickness of the remaining tendon helps estimate the extent of the lesion.

Full-thickness tear

Transfixing discontinuity of the tendon, the so-called naked cartilage sign — when the humeral head is covered only by cartilage, with no tendon overlying it —, retraction of the tendon stump and, in chronic cases, atrophy of the corresponding muscle are the findings that suggest a full-thickness tear.

The anisotropy pitfall

Anisotropy — the signal dropout that appears when the ultrasound beam does not strike the tendon fibers perpendicularly — is the most common cause of false positives in rotator cuff assessment. Repositioning the transducer before concluding there is pathological hypoechogenicity is a simple step that avoids this error.