Introduction

Perthes' disease is a degenerative condition affecting the hip joints of children, typically between the ages of 4-8 years. It is due to avascular necrosis of the femoral head, specifically the femoral epiphysis. Impaired blood supply to the femoral head causes bone infarction.

Classification

Catterall staging

StageFeatures
Stage 1Clinical and histological features only
Stage 2Sclerosis with or without cystic changes and preservation of the articular surface
Stage 3Loss of structural integrity of the femoral head
Stage 4Loss of acetabular integrity

Epidemiology

  • Incidence: 2.00 cases per 100,000 person-years
  • Peak incidence: 6-15 years
  • Sex ratio: more common in males 5:1
Condition Relative
incidence
Transient synovitis15.00
Perthes' disease1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Aetiology

Perthes' disease is 5 times more common in boys. Around 10% of cases are bilateral

Clinical features

Features
  • hip pain: develops progressively over a few weeks
  • limp
  • stiffness and reduced range of hip movement

Investigations

Diagnosis
  • plain x-ray
    • early changes include widening of joint space, later changes include decreased femoral head size/flattening
  • technetium bone scan or magnetic resonance imaging if normal x-ray and symptoms persist

Management

Management
  • To keep the femoral head within the acetabulum: cast, braces
  • If less than 6 years: observation
  • Older: surgical management with moderate results
  • Operate on severe deformities

Complications

Complications
  • osteoarthritis
  • premature fusion of the growth plates

Prognosis

Prognosis
  • Most cases will resolve with conservative management. Early diagnosis improves outcomes.