- It affects more boys than girls (4:1)
- Usually presents between 4 and 8 years of age. ( can have a secondary peak between 10 and 12 years ).
- Caucasians are affected more frequently than other races.
- Occurs in approximately 5.5 of 100,000 children per year (and therefore a lifetime risk of developing the disease is about 1 per 1200 individuals)
Although the cause is not clear it occurs in those with a delayed skeletal maturation and also there is an increased incidence with a positive family history or in children with a history of low birth weight.
- Pain (may present with referred pain in the knee).
- Decreased range of motion.
- Limping gait.
- There are 4 clinical stages: Initial stage, fragmentation, healing and residual.
Differential Diagnosis includes:
- Septic arthritis.
- Epiphyseal dysplasia.
A plain X-ray of the pelvis with both hips anterio-posterior and in lateral position helps in the diagnosis.
The aim of the management is to maintain the range of movement and to contain the femoral head in the acetabulum. Soft tissue release and corrective osteotomy may be required to achieve this.