Legg–calvé–perthes Disease

Basics

Idiopathic avascular necrosis of the femoral head in children 4–12 yr
Genetics:
- Increased frequency with factor V Leiden and anticardiolipin antibodies
- Usually sporadic but small percentage associated with type 2 collagen COL2A1 gene mutations

Pediatric Considerations
Exclusively a pediatric disease

Idiopathic avascular necrosis from interruption of blood supply to the femoral head from ischemia/occlusion, followed by reossification, deformity, and mechanically weakened bone
May be multifactorial
Risk factors include secondhand exposure to tobacco smoke, wood smoke, low birth weight, birth length <50 cm, delayed skeletal maturity, trauma, coagulation disorders
Gradual progression through 4 stages of disease:
- Initial stage: Dense femoral head causing intermittent synovitis
- Fragmentation: Femoral head becomes soft and deforms causing loss of motion
- Healing: New bone grows into femoral head
- Residual: Healed femoral head with some deformity
Most commonly occurs between ages 3–7; male > female, 4:1; Caucasians
Typically unilateral, but bilateral in 10–15% of cases
Associated with short stature, delayed and disproportionate growth

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