Multipartite patella

Last revised by Dr Mostafa El-Feky on 03 Feb 2022

Multipartite patella is an uncommon congenital abnormality that represents normal variant pathology and is a result of a failure of ossification during development. It is most commonly diagnosed as an incidental finding. 

The vast majority of multipartite patellae are asymptomatic, but direct trauma may disrupt the synchondroses resulting in symptoms. 

Segmentation of the patella occurs when there is a failure of fusion of the ossification centers in early childhood. The most common type of segmentation results in the separation of the upper outer quadrant which is called bipartite patella. More rarely, there may be a third segment resulting in a tripartite patella.

These are often incidental radiographic findings that have been classified into three types - the Saupe classification 1:

  • type I: at the inferior pole (5% of all lesions)
  • type II: at the lateral patellar margin (20%)
  • type III: at the superolateral pole (75%)

Thus, by far the commonest location of segmentation anomalies in the patella occurs at the superolateral border.

It is important to distinguish the multipartite patella from a patellar fracture in a symptomatic patient. If patellar fragmentation involves portions of the patella other than the upper and lower outer quadrants, then traumatic fracture should be considered.

  • impingement of multipartite patella 4-6

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Cases and figures

  • Case 1: multipartite patella
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  • Case 1: annotated
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  • Case 2
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  • Case 3: causing impingement
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  • Case 4: tripartite patella
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  • Case 5: tripartite patella
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  • Case 6: tripartite patella
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