In seven children in whom congenital dislocation of the hip was
diagnosed after they began to walk, magnetic resonance imaging provided
important information for treatment. In five children, it revealed adhesion
of the capsule to the ilium, an inverted limbus, and a displaced transverse
ligament; these findings indicated a need for open reduction. In the other
two children, magnetic resonance imaging demonstrated that the capsule was
redundant and appeared to have been stripped from the posterosuperior part
of the acetabular rim; this allowed closed reduction. Repeat
magnetic-resonance imaging in these two hips suggested that the capsule
gradually shrank after several months. The findings in these two patients
suggested a long-standing Grade-I congenital dislocation of the hip, as
described by Dunn and by Ogden. Children who have this type of congenital
dislocation can be treated with closed reduction, provided there is
prolonged immobilization of the hip.