53-year-old male with long-standing load-dependent anterior knee pain for approximately 18–24 months. Symptoms are provoked by activities such as jumping, running, stair climbing, deep knee flexion, or explosive push-off movements. The affected side is the left knee.
Ultrasound examination of the patellar tendon demonstrates thickening of the proximal patellar tendon, consistent with jumper’s knee or proximal patellar tendinopathy. The affected tendon measures 10.6 mm in thickness, compared with 6.0 mm on the contralateral, non-affected side.
The tendon is hypoechoic with loss of the normal fibrillar echotexture. Several small anechoic intratendinous foci are visible, compatible with focal degenerative change. Small interstitial microtears cannot be completely excluded. Doppler examination demonstrates moderate neovascularization within the abnormal tendon.
At the origin of the patellar tendon, mild cortical irregularity is present. There is no evidence of a complete patellar tendon rupture.
The sonographic appearance is consistent with chronic proximal patellar tendinopathy, corresponding to Popkin-Golman/Blazina grade 2 in combination with the long-standing clinical history and load-related pain.
1. Final diagnosis
Chronic proximal patellar tendinopathy, also known as jumper’s knee, with marked tendon thickening, hypoechogenicity, loss of normal fibrillar structure, moderate neovascularization, and mild cortical irregularity at the tendon origin. No complete patellar tendon rupture is present.
2. Differential diagnosis
The primary diagnosis is chronic tendinopathy of the proximal patellar tendon. A focal interstitial partial tear within a degenerative tendon may be considered, especially because of the anechoic intratendinous foci. Less likely diagnoses based on the current ultrasound appearance include complete patellar tendon rupture, infrapatellar bursitis, acute enthesitis, or primary intra-articular knee pathology.
3. Teaching points
Patellar tendinopathy typically affects the proximal patellar tendon near the inferior pole of the patella. Key ultrasound findings include tendon thickening, hypoechogenicity, loss of the fibrillar pattern, intratendinous degenerative foci, and Doppler neovascularization. Comparison with the contralateral side is useful, as demonstrated by the increased tendon thickness of 10.6 mm compared with 6.0 mm on the non-affected side.
4. Injury/disease information
Jumper’s knee is a chronic overload tendinopathy commonly associated with repetitive jumping, sprinting, running, stair climbing, and deep knee flexion. Symptoms are often related to impaired load tolerance of the tendon rather than a single acute injury. Conservative treatment is usually based on load management and progressive tendon-loading exercise therapy, such as eccentric training or heavy slow resistance training. Corticosteroid injection around or into the patellar tendon is generally used with caution because of the risk of tendon weakening and the lack of durable benefit in chronic tendinopathy.
Marc is founder of, and trainer at, SonoSkills. SonoSkills is an organization dedicated to MSK ultrasound education. He's also an MSK Sonographer at EchoConsult in Roermond, the Netherlands.
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