Tendinopathies are chronic tendon disorders caused by overuse, degeneration, or trauma. They are common in athletes and repetitive-stress occupations. Imaging is essential for diagnosis, grading severity, and guiding management.
📌 Why Image Tendinopathies?
- To differentiate tendinitis (inflammatory) from tendinosis (degenerative).
- To detect partial or full-thickness tears.
- To evaluate associated bursitis or enthesopathy.
- To monitor healing and response to treatment.
🔍 Imaging Modalities
1. Ultrasound (USG)
- First-line, dynamic, cost-effective.
- Findings:
- Tendinosis → thickened tendon, heterogeneous hypoechoic texture.
- Hyperemia on Doppler = active inflammation.
- Tears → focal hypoechoic/anechoic defect, loss of fibrillar pattern.
- Calcific tendinopathy → echogenic foci with posterior shadowing.
2. MRI
- Gold standard for complex and deep tendons.
- Findings:
- Tendinosis: Thickened tendon, increased signal on T1/T2, but no fiber discontinuity.
- Tear: Fluid-signal gap (partial or complete rupture).
- Peritendinous edema, bursitis, bone marrow edema often coexist.
3. Radiographs
- Usually normal.
- Can show calcific tendinopathy and bone changes at enthesis.
📍 Common Sites of Tendinopathy
1. Shoulder (Rotator Cuff Tendons)
- Supraspinatus: Most common site; critical zone injury.
- MRI: Increased signal, partial/full-thickness tear, retraction in complete tears.
- USG: Loss of fibrillar echotexture, anechoic defect, dynamic impingement.
2. Elbow
- Lateral epicondylitis (Tennis Elbow): Extensor tendon origin degeneration.
- Medial epicondylitis (Golfer’s Elbow): Flexor origin tendinopathy.
3. Knee
- Patellar tendon (“Jumper’s Knee”): Thickened tendon, focal increased T2 signal.
- Quadriceps tendon: Common in weightlifters and older patients.
4. Ankle & Foot
- Achilles tendon: Classic site of overuse tendinosis.
- MRI: Thickening, increased signal, partial/full rupture.
- USG: Hypoechoic tendon, dynamic evaluation possible.
- Plantar fascia (Plantar fasciitis): Enthesopathy, thickened fascia at calcaneal origin.
5. Hip
- Gluteal tendinopathy: Often associated with greater trochanteric pain syndrome.
📌 Teaching Pearls
- Tendinosis ≠ inflammation → it’s degeneration.
- USG is first-line; MRI is confirmatory and best for pre-surgical mapping.
- Always check for associated bursitis, enthesopathy, and muscle injury.
📊 USG vs MRI in Tendinopathy
| Feature | Ultrasound (USG) | MRI |
|---|---|---|
| Availability & Cost | Widely available, cheaper | Expensive, less available |
| Radiation | None | None |
| Dynamic Evaluation | ✅ Yes (real-time assessment, tendon movement, impingement) | ❌ No |
| Resolution | High spatial resolution for superficial tendons | Excellent for both superficial & deep tendons |
| Findings in Tendinosis | Thickened, hypoechoic, heterogeneous tendon; Doppler hyperemia | Thickened tendon, increased T1/T2 signal, intact fibers |
| Findings in Tear | Anechoic gap, fiber discontinuity | Fluid-signal gap, retraction in complete tear |
| Calcification Detection | ✅ Very good (echogenic foci with shadowing) | Limited (appears as low signal) |
| Associated Pathology | Can detect bursitis, synovitis, enthesopathy | Better for marrow edema, muscle involvement, deep bursae |
| Operator Dependence | High (needs expertise) | Low (standardized sequences) |
✅ Takeaway:
- USG = first-line, quick, dynamic, great for calcifications.
- MRI = gold standard for complex/deep tendons, surgical planning, and associated bone/muscle pathology.
