Multipartite patella

Multipartite patellae are uncommon congenital abnormalities that represent normal variant pathology and are 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. 

Classification

Segmentation of the patella occurs when there is a failure of fusion of the ossification centres in early childhood. The most common type of segmentation results in 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 have been classified into three types - the saupe classification1

  • 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 occur at the superolateral border.

Associations

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

Lower limb anatomy
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Article Information

rID: 20885
Section: Anatomy
Synonyms or Alternate Spellings:
  • Tripartite patella

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Cases and Figures

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    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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