A Study of Status of Reduction in Developmental Dysplasia of the Hip Using Arthroscopy

Using arthroscopy, we studied the status of reduction in developmental dysplasia of the hip. Hips were examined in 2 boys and 15 girls, aged 5 months to 3 years (average, 1 year 4 months). All joints were irreducible and treated with Pavlik harness or overhead traction. We performed hip arthroscopy using a medial approach with a 2.7-mm arthroscope under general anesthesia and observed the status of reduction during manipulation. We classified the status of reduction into four types: type 1, the femoral head remained outside the acetabular labrum and was irreducible (7 joints) ; type 2, the femoral head was moved on the labrum but was incompletely reducible (4 joints) ; type 3, the top of the femoral head was moved over the labrum but was incongruent and arthroscopically visible (2 joints); and type 4, the femoral head was completely reducible and arthroscopically invisible (4 joints). Type 1 joints were treated with open reduction, and type 2 joints were treated with either open reduction or closed reduction. Joints of types 3 and 4 were treated with closed reduction. Hip arthroscopy is useful for selective screening of irreducible developmental dysplasia of the hip.