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Fabella

Case contributed by Henry Knipe
Diagnosis certain

Presentation

Fall at the races. Tender patella.

Patient Data

Age: 55 years
Gender: Male
x-ray

No fracture or malalignment. No definite knee joint effusion. Pre-patella soft tissue swelling consistent with bruising/hematoma given recent history of trauma. Incidental note of a fabella.      

Annotated image

Red circle highlights the fabella. 

Case Discussion

A fabella is a common accessory ossicle found in the lateral tendon of the gastrocnemius. It should not be confused for a fracture or an ossified intra-articular body.

Pre-patella soft tissue swelling is well seen on lateral knee radiographs and important to comment on as it is often clinically confused for a joint effusion. 

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