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Patella Infera in TKA
By David Dejour, Yves Malemo, Guillaume Demey in category FOLLOW-UP
Lyon Ortho Clinic, 29B avenue des sources, 69009 Lyon
Patella infera (or patella baja) described by Caton, Deschamps et al in 1982, and then by Noyes in 1991, is defined by a patellar index less than or equal to 0.6.1,2 It can be congenital and is therefore not pathological or acquired leading to characteristic symptoms.
This rare disorder is sometimes found in the context of total knee arthroplasties (TKAs), thereby aggravating the final outcome. Therapeutic solutions are fairly limited, and the results are sometimes disappointing.
The aim of this article is to review the causes of patella infera after TKA and the therapeutic options. Finally, we will suggest a unique surgical technique.
2- Radiological measures of the patellar height
Several radiological indices measuring patellar height have been described. The three most widely known indices include the Caton–Deschamps index, the Blackburne–Peel index and the Insall–Salvati index (Image 1).
The Caton–Deschamps index was described in 1982. The AT/AP ratio is the ratio between the length of the patellar joint surface (AP) and the distance between the lower edge of the patellar joint surface to the anterosuperior edge of the tibia (AT). It is...
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