Bipartite patella

Case contributed by Weiling Tan
Diagnosis certain

Presentation

Pain over the right patella, with no history of trauma.

Patient Data

Age: 35 years
Gender: Male
x-ray

The two patella bone components show round edges at their opposing aspects, with the minor component at the lateral aspect of the major one. This configuration more likely represents bipartite patella rather than fracture as there is also no significant surrounding superficial soft tissue swelling. 

Case Discussion

Bipartite patellas are normal variants. They result from the emergence of a secondary ossification center that does not fully fuse with the primary ossification center, resulting in a nonunion or malunion 1.

In the skyline view, the accessory patellar fragment can be seen extending laterally, with a fragment connected to the main body of the patella 2. This helps differentiate from the differential diagnosis of a patella fracture. 

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