DEFINITION:

A disorder of the hip characterized by displacement of the femoral head on the femoral neck.

EPIDEMIOLOGY:

• incidence: 1/100,000
  • most common hip disorder of adolescence
• age of onset:
  • mean: M (13 years), F (11 years), rare before age 9
• risk factors:
  • overweight
  • physically immature
  • end stage renal failure
  • hormonal imbalance (hypogonadal, hypothyroid)
  • M > F (2:1)
  • blacks > whites (2:1)
  • trauma

PATHOGENESIS:

• this disorder is characterized by a combination of growth and altered mechanical properties of the proximal femoral growth plate which leads to structural weakness, failure, and displacement of the femoral head on the femoral neck due to a reduced resistence to shear stress; may be gradual or sudden
• 20% bilateral and 2/3 rds of these are simultaneous
• may be classified as acute or chronic (> 3 wks)

CLINICAL FEATURES:

INVESTIGATIONS:

MANAGEMENT: