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Developmental Dysplasia of the Hip

Developmental dysplasia of the hip (DDH) is a disorder that may be detected in neonates. The hips at birth are rarely dislocated but rather "dislocatable." Dislocations tend to occur after delivery. The cause of DDH is multifactorial, having both physiologic and mechanical factors. The positive family history (20%) and the generalized ligamentous laxity are related etiologic factors. The majority of children with DDH have generalized ligamentous laxity, and this can predispose to hip instability. Maternal estrogens and other hormones associated with pelvic relaxation result in further, although temporary, relaxation of the newborn hip joint.

Approximately 60% of children with typical DDH are firstborn, and 30-50% developed in the breech position. The frank breech position with the hips flexed and the knees extended is the position. There is also an association of congenital muscular torticollis (14-20%) and metatarsus adductus (1-10%) with DDH. The presence of either condition requires a careful examination.

Postnatal factors are also important determinants. Maintaining the hips in the position of adduction and extension may lead to dislocation. This puts the unstable hip under pressure because of the normal hip flexion and abduction contractures. An unstable femoral head, as a consequence, can be displaced from the developmental dysplasia of the hip.


Because hips are not dislocated at birth, the components of the hip joint, excluding the hip capsule and ligamentum teres, are relatively normal. There may be some variations in the shape of the cartilaginous acetabulum, especially if the child developed in a breech position. If a dislocation is allowed to occur, then acetabular dysplasia and maldirection, excessive femoral anteversion (torsion).


The Barlow test is the most important maneuver in examining the newborn hip. This provocative test to dislocate an unstable hip is performed by stabilizing the pelvis with one hand and then flexing and adducting the opposite hip and applying a posterior force. If the hip is dislocatable, it is usually readily felt. After release of the posterior force, the hip will usually spontaneously relocate.

Limitation of hip abduction is indicative of soft tissue contractures and may indicate DDH. Conversely, hip abduction contractures may indicate dysplasia of the contralateral hip.

A common concern is the presence of hip clicks in infants. Hip clicks per se are usually not pathologic and are secondary to (1) breaking the surface tension across the hip joint, (2) snapping. In older or walking children, complaints of limping, waddling, increased lumbar lordosis, toe walking, and leg-length discrepancy.


Hip stability as well as acetabular development may accurately be assessed by ultrasonography. Radiographic evaluation in older infants and children. The ossific nucleus of the femoral head does not appear until 3-7 mo of age, and it may be further delayed in DDH. Line measurements are usually made to determine the relationship of the femoral head to the acetabulum (acetabular index, quadrant assessment, Shenton line, and the center edge angle of Wiberg).


The treatment of DDH should be individualized and depends on the patient's age and whether the hip is subluxated or dislocated.


When an unstable hip is recognized at birth, maintenance of the hip in the position of flexion and abduction ("human" position) for 1-2 mo is usually sufficient. This position maintains reduction of the femoral head and allows for tightening of the ligamentous structures as well as for stimulation of normal growth and development. Methods that can be used to maintain the hip in this position include Pavlik harness, Frejka splint, and a variety of 

Double and triple diapers, although controversial, are commonly used in infants with dislocatable hips because the latter devices usually do not fit satisfactorily.

Age of 1-6 Mos

During this age, a true dislocation may develop. As a consequence, treatment is directed toward reduction of the femoral head into the acetabulum. The Pavlik harness is the major mode of treatment in this age group. The harness attempts to place the hips in the human position by flexing them more than

Age of 6-18 Mo

In the older infant, surgical closed reduction is the major method of treatment. If the reduced hip shows

Age of 18 Mo-8 Yr

After 18 mo of age, the progressive deformities are so severe that open reduction followed by pelvic (innominate) osteotomy, femoral osteotomy, or both are necessary to realign the hip. A femoral shortening derotation osteotomy is performed concomitantly if the reduction is tight, if there is 


The most important and severe complication of DDH is avascular necrosis of the CFE. This is an iatrogenic complication; reduction of the femoral head under pressure produces cartilaginous compression, and this can result in occlusion of the intra-articular, extraosseous epiphyseal vessels and