Background: A common pathologic finding in the knee associated with
congenital longitudinal deformity is aplasia of one or both cruciate
ligaments. We performed a radiographic analysis to assess the changes in the
femoral intercondylar notch and the tibial eminence in relation to the status
of the cruciate ligaments.
Methods: Thirty-four knees in thirty-one patients with longitudinal
congenital deficiency of the lower limb were evaluated. The cruciate ligaments
and the associated abnormalities of the distal aspect of the femur and the
proximal aspect of the tibia were evaluated with use of magnetic resonance
imaging and a tunnel view radiograph.
Results: We differentiated three main types of dysplasia of the
cruciate ligaments with typical associated changes. In type I, partial closure
of the femoral intercondylar notch and hypoplasia of the tibial eminence are
observed and the anterior cruciate ligament is hypoplastic or aplastic. In
type II, these findings are accentuated and there is additional hypoplasia of
the posterior cruciate ligament. In type III, the femoral intercondylar notch
and the tibial eminence are completely absent and there is aplasia of both
Conclusions: We delineated three types of congenital deficiency of
the cruciate ligaments and found corresponding morphologic changes of the
femoral notch and the tibial eminence, which can be observed on tunnel view
radiographs. Thus, the diagnosis and differentiation between aplasia of one or
both cruciate ligaments and between congenital and trauma-induced absence of
the cruciate ligaments may be made by interpreting plain radiographs.
Level of Evidence: Diagnostic Level III. See Instructions
to Authors for a complete description of levels of evidence.