Overview
Also known as Legg-Calvé-Perthes disease, Perthes’ disease (PD) is a degenerative disorder of the hip joint in children aged 3-10 years old. It occurs due to avascular necrosis (death of bone tissue due to an interrupted blood supply) of the femoral head. The exact cause of this interruption in blood supply is unknown.
Early diagnosis and management are important, as younger children (around <6 years old) have more potential for the dead bone to revascularise and remodel, which can lead to recovery of the femoral head.
Epidemiology
- Perthes’ disease is around 5 times more common in boys than girls
- Perthes’ disease is most common in children aged 3-10 years old
Presentation
Symptoms emerge over a few weeks with no history of trauma:
- Hip pain that leads to a limitation in movements of the hip and a limp
- There may be referred pain in the groin
- Usually unilateral – around 10% of cases are bilateral
- Children may place more weight on their unaffected leg – antalgic gait
- In later stages, there may be a Trendelenburg gait
There are no constitutional symptoms and there is no evidence of joint inflammation.
Investigations
Overview
- X-ray of hips:
- May show flattening and/or a decreased size of the femoral head
- May show widened joint space
- MRI of hips:
- May show features described above under X-ray
- Bone scintigraphy (technetium bone scan):
- May show ‘cold spots’ in the affected hip
Management
Overview
The mainstay of management is to treat pain and reduce the loss of hip motion. Options include:
- Restriction of activities and weight-bearing until ossification completes (a brace or cast may be considered)
- NSAIDs for pain relief
- Surgery – indicated for older children or those with severe deformities
Complications
- Osteoarthritis
- Limb length discrepancy
- Premature fusion of the growth plates and short stature
Prognosis
- Children <6 years old have a better prognosis as they have higher bone remodelling potential
- More than 80% of affected hips have very good outcomes that persist until 30-40 years, however, osteoarthritis and ongoing hip problems are common
