Congenital absence of the cruciate ligaments

Last revised by Arlene Campos on 12 Jan 2024

Congenital absence of the cruciate ligaments is a rare condition, most of the knowledge being collated from case reports. 


Its prevalence is reported at 0.017 per 1000 live births 1,5.


The following features may also be present 2,3,5:

  • lateral femoral condyle hypoplasia
  • tibial intercondylar spines hypoplasia
  • absent/abnormal meniscus
  • congenital femoral shortening
  • defects in the fibular head and its associated muscles
  • patellar dislocation


Combined congenital absence of the anterior and posterior cruciate ligaments is a rare condition. The isolated congenital absence of anterior cruciate ligament (ACL), while rare, is more common than the isolated absence of posterior cruciate ligament (PCL), which is usually associated with the absence of the ACL 2.

  • type I: hypoplastic or aplastic ACL and normal PCL
  • type II: aplastic ACL in combination with a hypoplastic PCL
  • type III: both cruciate ligaments are aplastic 4,5

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Cases and figures

  • Case 1: absent ACL
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  • Case 2: absent ACL
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