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Patellar tendinopathy, commonly known as jumper’s knee, is a chronic overuse injury of the patellar tendon, typically at its proximal insertion on the inferior pole of the patella. It occurs most frequently in athletes involved in sports requiring repetitive jumping, sprinting, or change of direction.
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https://www.youtube.com/watch?v=yEregcEHQt4
| Feature | Description |
|---|---|
| Tendon degeneration | Non-inflammatory microtrauma → collagen disruption, neovascularization, mucoid degeneration |
| Location | Most often at the proximal third of the patellar tendon (patellar enthesis) |
| Histopathology | Tendinosis (degenerative) rather than true tendonitis (inflammatory) |
| Feature | Description |
|---|---|
| Age group | Adolescents and young adults (especially athletes) |
| Symptoms | Anterior knee pain, localized over inferior pole of the patella |
| Aggravated by | Jumping, running, stair climbing, deep squatting |
| Onset | Gradual; activity-related |
| Physical exam | Tenderness over patellar tendon, pain on resisted knee extension |
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MRI hallmark: Focal tendon thickening with increased signal intensity on T2-weighted sequences, especially at the patellar insertion.
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| Modality | Imaging features |
|---|---|
| MR | • T1: May show thickened tendon, iso- to hypointense signal |
| • T2/STIR: Increased signal intensity at the proximal posterior patellar tendon | |
| • Chronic changes: Tendon thickening, loss of fibrillar pattern, enthesophytes | |
| US | • Focal or diffuse tendon thickening |
| • Hypoechoic areas: Indicative of degeneration | |
| • Neovascularity (color Doppler): Often present in chronic tendinosis | |
| • Calcifications: May be seen in chronic cases | |
| XR | Inferior pole irregularity: Enthesophytes or calcification in chronic tendinopathy |
Patellar tendinosis. Proton density fat-suppressed images (A,B) show increased signal intensity of the patellar tendon at its patellar attachment (arrow), without focal tear consistent with moderate tendinosis of the proximal patellar tendon.
The images were obtained from the University of Washington Medical Imaging database.. Masroori Z, Haseli S, Abbaspour E, Pouramini A, Azhideh A, Fathi M, Kafi F, Chalian M. Patellar Non-Traumatic Pathologies: A Pictorial Review of Radiologic Findings. Diagnostics. 2024; 14(24):2828. https://doi.org/10.3390/diagnostics14242828
| Condition | Key Differentiating Features |
|---|---|
| Sinding-Larsen-Johansson syndrome | Younger age; apophyseal fragmentation of patellar apex |
| Osgood–Schlatter disease | Pain at tibial tubercle, not patella |
| ‣ | Diffuse anterior knee pain; no focal tendon abnormality |
| Prepatellar bursitis | Fluid anterior to tendon/patella; not tendon-related |
| Partial tendon tear | High-grade focal tendon discontinuity; acute onset |
| Approach | Description |
|---|---|
| Activity modification | Reduce jumping, high-impact activities |
| Physiotherapy | Eccentric strengthening of quadriceps, hamstring stretching |
| NSAIDs / Cryotherapy | For pain control |
| Ultrasound-guided injection | PRP, corticosteroids (less favored), or dry needling |
| Shockwave therapy | For chronic, nonresponsive cases |
| Surgical intervention | Rare; for recalcitrant or partially torn tendons (arthroscopic debridement) |