Developmental Dysplasia (From Required Medscape Readings)

Question 1

Developmental dysplasia of the hip (DDH) is an ambiguous umbrella term. Explain some of the general characteristics.

Answer 1

DDH implies any abnormality in the anatomy of the femur or pelvis that leads to functional impairment (whether from pain, impingement, or dislocation). It can occur at any time from conception to adulthood. Multiple structures may be the cause: femur anomalies, labral dysfunction, or misshapen acetabulum.

Question 2

What does subluxation mean and how is it different from dislocation?

Answer 2

Subluxation means insufficient contact between two articulating bones. Dislocation implies a complete lack of contact.

Question 3

Some people think ligamentous laxity correlates with DDH. What evidence makes this seem less likely?

Answer 3

Disorders that lead to laxity of collagen in ligaments (Ehlers-Danlos and Marfan) do not increase the risk of DDH.

Question 4

What things increase the risk of DDH?

Answer 4

• Genetic predisposition (children of parents with DDH are 10x more likely to have DDH)
• Uterine crowding (multiple gestations, oligohydramnios, breech presentations)

Question 5

The frequency of DDH is roughly __________.

Answer 5

1 : 1,000