The Barlow test attempts to dislocate an unstable hip (Fig. 199-2). The examiner should stabilize the infant’s pelvis with one hand and grasp the abducted and flexed thigh in the other hand. The hip should be flexed to 90°. Next, begin to adduct the hip, while applying a posterior force to the anterior hip. A hip that can be dislocated in this method is readily felt (clunk feeling) and is a positive test. It may reduce spontaneously once the posterior force is removed, or the examiner may need to perform the Ortolani test.
The Ortolani test may reduce a dislocated hip (Fig. 199-3).The examiner should stabilize the pelvis and hold the leg in the same method as for the Barlow test. The infant’s hip should be in 90° of flexion. Abduct the hip while applying anterior pressure to the posterior thigh. A positive test is the palpable reduction of the dislocation, which may be felt (clunk). After 2 months of age, the hip may develop muscular contractures, preventing positive Ortolani tests.
These tests should be performed with only gentle force and done one hip at a time. The test may need to be repeated multiple times, as they can be difficult to interpret. A click, which is not pathologic, may occur from breaking the surface tension of the hip joint or snapping gluteal tendons.
Bilateral fixed dislocations present a diagnostic dilemma because of the symmetry on exam. The Klisic test is useful in this situation; it is done by placing the third finger over the greater trochanter and the index finger over the anterior superior iliac spine, then drawing an imaginary line between the two. The line should point to the umbilicus in a normal child. However, in a dislocated hip, the greater trochanter is elevated, which causes the line to project lower (between the umbilicus and pubis). This test is helpful identifying bilateral DDH, which can otherwise be difficult to diagnose because of the symmetry found on examination.
Older children with unrecognized DDH may present with limping. A patient with increased lumbar lordosis and a waddling gait may have an unrecognized bilateral DDH.
Figure 199-2 Barlow (dislocation) test. Reverse of Ortolani test. If the femoral head is in the acetabulum at the time of examination, the Barlow test is performed to discover any hip instability. A, The infant’s thigh is grasped as shown and adducted with gentle downward pressure. B, Dislocation is palpable as the femoral head slips out of the acetabulum. Diagnosis is confirmed with the Ortolani test.
Figure 199-3 Ortolani (reduction) test. With the infant relaxed and content on a firm surface, the hips and knees are flexed to 90°. The hips are examined one at a time. The examiner grasps the infant’s thigh with the middle finger over the greater trochanter and lifts the thigh to bring the femoral head from its dislocated posterior position to opposite the acetabulum. Simultaneously the thigh is gently abducted, reducing the femoral head in the acetabulum. In a positive finding, the examiner senses reduction by a palpable, nearly audible clunk.
Ultrasound is used for initial evaluation of infants with DDH. Ultrasonography is necessary for girls with a positive family history or breech presentation in both sexes. This should be obtainedafter 6 weeks of age to avoid confusion with physiologic laxity.Because the femoral head begins to ossify at 4 to 6 months of age,plain radiographs can be misleading until patients are older.
The treatment of DDH is individualized and depends on the child’s age at diagnosis. The goal of treatment is a stable reduction that results in normal growth and development of the hip. If DDH is suspected, the child should be sent to a pediatric orthopedic specialist.