Diagnostic Evaluation of Biceps Tendon Rupture

Clinical Examination – Distal Biceps

The combination of the Hook test and biceps‑crease‑interval (BCI) measurement yields 100 % specificity for acute complete distal‑biceps ruptures when both tests are positive, according to the American College of Radiology. 1

Non‑contrast MRI is the reference standard, demonstrating 86.4 % accuracy for identifying complete distal‑biceps tears, outperforming ultrasound (45.5 % accuracy). Evidence cited by the American College of Radiology. 1
For detection of any biceps‑tendon tear (complete or partial), MRI shows 76 % sensitivity and 50 % specificity. 1
MRI provides superior detection of partial‑tear lesions and tendinopathy compared with ultrasound, as reported by the American College of Radiology. [1][2]

Operator‑dependent ultrasound achieves 62.5 % sensitivity and 20 % specificity for biceps‑tendon tears, markedly lower than MRI performance. [1][2]
In the hands of skilled operators, ultrasound is equivalent to MRI for complete ruptures but remains less reliable for partial‑tear identification. 2
A medial imaging approach for ultrasound yields substantial inter‑reader agreement, supporting its reproducibility. [3][2]

The FABS view (patient prone, elbow flexed 90°, shoulder abducted, forearm supinated) enables visualization of the entire distal‑biceps tendon on a single image. [1][4]3
This view is most useful for distinguishing high‑grade partial tears from complete ruptures by revealing residual tendon fibers. [1][3]
Compared with standard MRI planes, the FABS view demonstrates better inter‑rater reliability, enhancing diagnostic consistency. [1][4]

The classic “Popeye deformity”—a visible bulge of the retracted biceps muscle belly—is a hallmark clinical sign of proximal long‑head rupture. [1][4]
The most common injury pattern is a partial rupture of the long head with an intact short head. [1][4]
89 % of atraumatic biceps‑tendon ruptures involve the long head of the biceps. [1][4]
MRI offers improved sensitivity for detecting partial tears of the proximal biceps compared with other modalities. [1][4]

All cited data are derived from peer‑reviewed studies referenced by the American College of Radiology; specific levels of evidence or grades of recommendation were not provided in the source material.

The American College of Radiology (ACR) rates both non‑contrast MRI of the shoulder and shoulder ultrasound as usually appropriate (9/9) for evaluating suspected proximal biceps tendon rupture, making either modality acceptable as the definitive diagnostic study. 5
Non‑contrast MRI of the shoulder is rated 9/9 (usually appropriate) by ACR guidelines for suspected biceps tenosynovitis or tendon pathology, reflecting strong evidence of its suitability. 6
Shoulder ultrasound is rated 9/9 (usually appropriate) when performed by operators with adequate expertise, providing an equivalent first‑line option. 6

MRI offers high sensitivity and specificity for detecting tendinosis, partial‑thickness tears, and full‑thickness tears of the long‑head biceps tendon. 5
MRI is superior for identifying associated rotator cuff tears, which are frequently present alongside proximal biceps ruptures. 5
MRI provides excellent visualization of the supraspinatus tendon, subacromial bursa, and biceps tendon, facilitating comprehensive assessment of concurrent pathology. 6

Ultrasound is equivalent to MRI for evaluating the long‑head biceps tendon and rotator cuff when performed by skilled operators. 7
The modality allows dynamic assessment, though its accuracy is operator‑dependent. 5
Ultrasound can be combined with therapeutic injection of anesthetic or corticosteroid when clinically indicated. 6

For distal biceps tendon rupture, MRI remains the gold‑standard, achieving 86.4 % accuracy for detecting complete tears. 8
The FABS (flexion‑abduction‑supination) view is recommended to differentiate partial from complete distal tears in challenging cases. 9
Ultrasound demonstrates lower accuracy (≈45.5 %) compared with MRI for distal ruptures, indicating it is less reliable for this location. 10

MR arthrography is rated 1/9 (usually not appropriate) for suspected biceps tenosynovitis or rupture, as natural joint effusion provides sufficient contrast without the need for intra‑articular contrast. 5