37-year-old patient presenting with slowly increasing posterior elbow pain localized to the olecranon region. Pain is reproducible on palpation at the triceps tendon insertion. Pain is worse after playing tennis and padel. No additional clinical history provided.
Ultrasound of the posterior elbow demonstrates a well-defined bony outgrowth (enthesophyte) at the insertion of the triceps tendon on the olecranon, measuring approximately 3.6 × 5.2 mm.
This finding corresponds precisely with the patient’s point of maximal tenderness. Palpation over the enthesophyte during dynamic assessment reproduces the patient’s recognizable pain, suggesting a clear correlation with symptoms.
The triceps tendon itself appears normal in echotexture and thickness, without signs of tendinopathy or partial tear. The olecranon bursa is not distended and shows no signs of bursitis. There is no evidence of neovascularization on Doppler imaging.
There are subtle features suggesting mechanical irritation or compression caused by the enthesophyte despite its relatively small size.
1. Final diagnosis
Symptomatic triceps tendon enthesophyte at the olecranon insertion, with mechanical irritation and reproducible pain on palpation.
2. Differential diagnosis
Consider insertional triceps tendinopathy, early olecranon bursitis, or less likely calcific enthesopathy without true osseous proliferation. Clinical correlation helps distinguish these entities.
3. Teaching points
Enthesophytes at tendon insertions may be small yet clinically significant when they cause focal mechanical irritation. Ultrasound-guided palpation is valuable to confirm symptom correlation. The absence of Doppler signal and normal tendon structure helps exclude active tendinopathy.
4. Injury/disease information
An enthesophyte is a bony proliferation at a tendon or ligament insertion, often related to chronic traction or degenerative change. At the triceps insertion, it may lead to localized pain due to mechanical conflict, especially during elbow extension or direct pressure.
Marc is founder of, and trainer at, SonoSkills. SonoSkills is an organization dedicated to MSK ultrasound education. He's also an MSK Sonographer at the Laurentius Hospital in Roermond, the Netherlands.
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