A 7-year-old boy presents with his parents with a month-long history of “running funny” while playing baseball this season. He does not complain of any pain and has not had any problems like this in the past. The patient and family deny any trauma, fevers, or chills. Radiograph of his pelvis is obtained and shows the early stages of Legg-Calve-Perthes disease (Figure 88-1).

Legg-Calvé-Perthes (LCP) disease is a juvenile form of idiopathic osteonecrosis of the femoral head. First described in 1910 as an entity separate from tuberculosis by Legg, Calvé, and Perthes in separate accounts. It still carries unresolved controversy regarding the etiology, pathogenesis, and management.

Perthes disease.

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  Can affect a wide age range of children aged 2 to 14 years, but most common at 5 to 8 years of age.

  
  
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  Male to female ratio 5:1.

  
  
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  Bilateral in 10 to 15 percent of cases.¹

  
  
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  Incidence is 5.1 to 16.9 per 100,000.²

Etiology

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  Probably multifactorial, exact cause still uncertain.

  
  
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  Possible factors—Trauma, susceptible child, hereditary factors, coagulopathy, hyperactivity, passive smoking, or collagen abnormality.³

  
  
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  Unlikely factors—Endocrinopathy, urban environment, or synovitis.³

  
  
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  Disruption of blood supply to the femoral head and a pathologic repair process cause imbalance of bone resorption and formation.¹

  
  
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  Current research focusing on cause of the vascular disruption including a missense mutation in the type II collagen gene in familial cases, thrombophilia also being investigated as possible cause although there are cases of LCP disease without either of these abnormalities.¹

Pathophysiology¹

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  Disruption of blood supply affects articular cartilage, bony epiphysis, physis, and metaphysis.

  
  
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  Cartilage:

  
  
  
  
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    Necrosis especially in the deep layer, cessation of enchondral ossification, separation from underlying bone followed by revascularization and new accessory ossification.

  
  
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  Bony Epiphysis:

  
  
  
  
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    Necrosis of marrow space, compression fractures of trabeculae, fibrovascular granulation tissue invasion, or osteoclastic resorption.

  
  
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  Physis:

  
  
  
  
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    Focal areas of growth cartilage columns extending below the endochondral ossification line mostly in the anterior aspect of the femoral head.

  
  
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  Metaphysis:

  
  
  
  
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    Physeal cartilage columns as mentioned above, fibrocartilage, fat necrosis, vascular proliferation, and fibrosis all described.

Clinical Features

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  Mild pain in groin, anterior hip, or around greater trochanter, knee pain.

  
  
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  Limp exacerbated by activity that improves with rest.

  
  
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  Insidious onset but commonly with antecedent trauma.

  
  
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  Hip irritability (increased pain with motion) due to synovitis.

  
  
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  Possible Trendelenburg gait (leaning over affected hip).

  
  
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  Trendelenburg sign—Unaffected side of pelvis drops when standing on affected hip alone and body sways to affected side.

  
  
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  Possible hip motion limitations depending on stage of disease—Lose abduction and internal rotation first. If in fragmentation stage severe restrictions:

  
  
  
  
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    Possible limb length discrepancy.

    
    
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    Possible thigh and calf muscle atrophy.