Traction apophysitis of the knee: A case report
Published in the journal Radiology Case Reports, the authors describe a case of a 12-year-old boy who presented with infrapatellar pain, with subsequent diagnosis of traction apophysitis of the knee (Sinding-Larsen-Johansson disease).

A 12-year-old boy was referred to our ultrasound department for persistent infrapatellar knee pain during longstanding seated positions and sporting activities. Patellar traction apophysitis (Sinding-Larsen-Johansson disease) was diagnosed by means of ultrasound assessment, and the patient was referred to sports physician for further treatment.

Ultrasound at the level of the inferior patella apex proved widening of the apophysis with bony irregularity at the tendon insertion site, presenting as apophysitis.

Focal thickening of the proximal insertion of the infrapatellar tendon insertion was noted in comparison to the contralateral side. Power Doppler showed subtle increased hyperemia within the tendon fibers of the intrapatellar tendon.

Conventional x-rays of the symptomatic right knee were reported as normal with no visible evidence of bony irregularity at the point of maximum tenderness. Incidental observation was made of cortical irregularity of the left asymptomatic knee, with loose bony fragment present.

Ultrasound proved superior in diagnosis of the disease process in its acute phase.

Learning Points:-
- Conventional radiographs are frequently reported with no significant findings in the acute setting, leading to ultrasound as the modality of choice for diagnostic efficacy of apophyseal traction injuries in young athletes.

- Sinding-Larsen-Johansson disease has a 2%-5% incidence in children aged 10-15 years, with the most common cause related to sporting activities related to jumping.

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