Presentation
Hyperextended right knee since birth.
Patient Data
The MRI sequences demonstrate an anterior tibial displacement with intact and elongated cruciate and collateral ligaments. No associated meniscal or osteochondral lesion is seen.
Case Discussion
MRI features of a congenital knee dislocation. No others associated musculoskeletal anomalies in this case.
Congenital dislocation of the knee is a rare malformation, usually present at birth and defined as a hyperextension deformity with variable degrees of anterior displacement of the tibia under the femur. Several etiologies have been proposed such as breech position of the fetus, oligoamnios with reduced intrauterine fetal space and fibrosis/contracture of the quadriceps. It may be seen as an isolated knee deformity (as in this case) or associated with other musculoskeletal anomalies (foot deformity, developmental dysplasia of the hip, arthrogryposis or Larsen syndrome).