Patella alta

Last revised by Dr Henry Knipe on 13 Oct 2021

Patella alta, or a high riding patella, describes a situation where the position of the patella is considered high. It may be idiopathic or may result secondary to a patellar tendon rupture

Epidemiology

Associations

Several conditions are known to be associated with patella alta, including:

  • idiopathic retropatellar pain 5
  • recurrent dislocation of the patella 2
  • chondromalacia patellae 2
  • knee joint effusion 2

Patella alta may also occur as a result of spastic cerebral palsy 6.

Radiographic features

On sagittal images, it is usually considered when the Insall-Salvati ratio is greater than 1.3-1.5 1-3.

On radiography, it is important that standard positioning is used, with the knee flexed at 30 degrees. An off-angle x-ray beam or non-standard positioning may result in a spuriously abnormal ratio.

Cases and figures

  • Case 1
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  • Case 2: modified Insall-Salvati index 2.2
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  • Case 3
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  • Case 4
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  • Case 5: secondary to a patella tendon rupture
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  • Case 6
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  • Case 7
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  • Case 8
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  • Case 9
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