Disorders of the Lower Extremity

Question 1

What are some risk factors for developmental hip dysplasia?

Answer 1

DDH is more common among females, firstborn children, and infants with a history of intrauterine crowding or breech presentation.

Question 2

Within what age range should the physician be screening regularly for developmental hip dysplasia?

Answer 2

Screen for DDH on physical exam from the time of birth until the child is walking well.

Question 3

What is developmental hip dysplasia?

Answer 3

DDH is a disruption of the normal contact between the acetabulum and the femoral head which prevents the hip joint from developing normally. It leads to hip subluxation and dislocation.

Question 4

When should the Barlow and Ortolani tests be used to screen for developmental hip dysplasia?

Answer 4

The Barlow and Ortolani tests will only be positive in the newborn period (until 8-10 weeks of age) because affected hips are no longer reducible after this time.

Question 5

What is the definition of a positive Barlow test?

Answer 5

A positive Barlow test is defined by movement (“clunk”) of a dislocated femoral head from the acetabulum as the examiner adducts the flexed hip while pushing the thigh posteriorly. ***include Figure 9-1

Question 6

What is the definition of a positive Ortolani test?

Answer 6

A positive Ortolani test is defined by movement (“clunk”) of the dislocated femoral head back into the acetabulum as the examiner holds the thigh between the thumb and index finger and lifts the greater trochanter while abducting the hip. ***include Figure 9-1

Question 7

What is the Galeazzi sign and at what age can one expect it to be seen?

Answer 7

The Galeazzi sign is defined by asymmetry in the height of the knees due to shortening of the thigh on the affected side. It is best observed with both hips placed in 90° flexion and can only be seen after 8-10 weeks of life.

Question 8

What physical exam findings would you look for to help diagnose developmental hip dysplasia in a child <8-10 weeks old?

Answer 8

Positive Barlow and Ortolani tests

Question 9

What physical exam findings would you look for to help diagnose developmental hip dysplasia in a child >8-10 weeks old?

Answer 9

Positive Galeazzi sign, limited hip abduction, asymmetry of the gluteal and thigh folds, and the “telescoping” or “pistoning” sign.

Question 10

What is the “telescoping”/”pistoning” sign?

Answer 10

It is a sign of hip instability elicited with the hip flexed to 90°: one hand stabilizes the pelvis at the ASIS while the other hand grasps the femur and applies gentle anterior>posterior force, causing the femur to slip out of the acetabulum in the unstable hip.

Question 11

How is developmental hip dysplasia diagnosed in an infant < 4-6 months of age?

Answer 11

In infants <4-6 months of age, evaluate with hip ultrasound; because the femoral head has not yet ossified, the cartilage and soft tissues are better delineated by this imaging modality.

Question 12

How is developmental hip dysplasia diagnosed in an infant > 4-6 months of age?

Answer 12

In infants > 4-6 months of age, DDH can be diagnosed using plain radiographs because the femoral heads have ossified by this time.

Question 13

What is the recommended treatment for developmental hip dysplasia?

Answer 13

In infants <6 months of age, use a Pavlik harness to hold the hip flexed so the femoral head stays in the socket and allows for proper hip joint development. From 6 months to 2 years of age, use a spica splint to attempt closed reduction. If these procedures are unsuccessful, surgery is indicated.

Question 14

What is Blount disease?

Answer 14

Blount disease is a pathologic varus malformation caused by abnormal growth of the medial portion of the proximal tibial physis. ***Include Figure 9-3

Question 15

What are the (4) risk factors for development of Blount disease?

Answer 15

African American ethnicity, early walking, obesity, and female gender.

Question 16

What are two forms of Blount disease, and how do they differ?

Answer 16

The two forms of the disease are infantile and adolescent. The infantile form is diagnosed before 4 years of age, is usually bilateral, and is seen in children of normal weight. Adolescent Blount disease is diagnosed at ≥4 years of age, is often unilateral, and is more commonly seen with obesity. The adolescent form can also present with pain and leg length discrepancy.

Question 17

What is the normal physiologic progression of genu varum/valgum throughout childhood?

Answer 17

The normal physiologic progression is genu varum up to 2 years of age, followed by genu valgum at approximately 3 years of age. By 7 years of age, most children return to the normal physiologic valgus.

Question 18

What is the modality required for diagnosis of Blount disease?

Answer 18

Plain radiograph

Question 19

What are the associated imaging findings for patients diagnosed with Blount disease?

Answer 19

Plain radiographs show metaphyseal beaking and a tibial metaphyseal-diaphyseal angle >16°.

Question 20

What is the recommended treatment for infantile Blount disease?

Answer 20

Treat with bracing for approximately 2 years. If bracing is unsuccessful or the metaphyseal-diaphyseal angle is >20°, surgery is indicated.

Question 21

What is the recommended treatment for adolescent Blount disease?

Answer 21

Surgical intervention is usually required for treatment of adolescent Blount disease.