Case Study

A.L. is a 4,100-g (9 lb, 1 oz), one-day-old boy born at 39 weeks’ gestation by cesarean section because of breech presentation following an uncomplicated pregnancy. One- and five-minute Apgar scores were 8 and 9, respectively. He has normal vital signs and activity and no gross deformities on his general assessment. As part of your examination, you perform the Ortolani and Barlow maneuvers and detect a hip dislocation on the Barlow test.

Case Study Questions

1. Based on information from the U.S. Preventive Services Task Force (USPSTF), which one of the following statements about developmental dysplasia of the hip (DDH) is correct?

• A. Limited hip abduction to identify DDH is most accurate in infants younger than three months.

• B. Strong evidence supports the effectiveness of surgical and nonsurgical early interventions for DDH.

• C. Most abnormal hips identified by newborn physical examination resolve spontaneously, requiring no intervention.

• D. Harms from treatment of DDH are mild and rare.

• E. Long-term complications of untreated DDH include avascular necrosis of the hip.

2. Which one of the following statements about this infant’s risk for DDH is correct?

• A. He is at increased risk because males are more likely than females to have DDH.

• B. He is at increased risk because of his breech position at birth.

• C. He is at increased risk because of his above-average birth weight.

• D. He is at decreased risk because he was delivered by cesarean section.

3. Which of the following statements is/are accurate and appropriate to discuss with A.L.’s parents?

• A. DDH includes dysplastic, subluxated, dislocatable, and dislocated hips.

• B. A long-term complication of DDH may be premature degenerative joint disease.

• C. An ultrasound examination will provide good information about whether the condition is likely to resolve spontaneously.

• D. The benefits of treatment for DDH before 12 months of age clearly outweigh the harms.

Answers

1. The correct answer is C. There is evidence that screening for DDH leads to earlier identification. However, 60 to 80 percent of the hips of newborns identified as abnormal or suspicious for DDH by physical examination (i.e., Barlow and Ortolani maneuvers) and more than 90 percent of those identified by ultrasonography resolve spontaneously, requiring no intervention. Limited hip abduction is a relatively insensitive and nonspecific marker of DDH in early infancy but becomes more accurate after three to six months of age and with more severely affected hips.

There is poor evidence (i.e., poor-quality studies) of the effectiveness of surgical and nonsurgical interventions. Harms from treatment of DDH are neither mild nor rare: avascular necrosis of the hip is reported in 0 to 60 percent of children who are treated for DDH but is not a complication of untreated DDH.

The USPSTF was unable to assess the balance of benefits and harms of screening for DDH but was concerned about the potential harms associated with treatment of infants identified by routine screening. Thus, the USPSTF concluded that evidence is insufficient to recommend routine screening for DDH in infants as a means to prevent adverse outcomes.

2. The correct answer is B. A.L. is at increased risk because of his breech position at birth. Other risk factors for DDH include female sex, family history of DDH, and in utero postural deformities. However, most infants with DDH have no identifiable risk factors. Above-average birth weight is not a known risk factor, and cesarean section is not known to be protective.

3. The correct answers are A and B. DDH represents a range of anatomic abnormalities in which the femoral head and the acetabulum either are in improper alignment or grow abnormally. The precise definition of DDH is controversial and includes dysplastic, subluxated, dislocatable, and dislocated hips. The lack of a normal tight, concentric anatomic relationship between the femoral head and acetabulum may result in permanent disability. Long-term complications of DDH include premature degenerative joint disease, impaired walking, and chronic pain.