The limping child often grabs our attention and makes us ponder many conditions, like Toddler’s Fracture, Septic Arthritis, SCFE, Osteomyelitis, and Growing Pains. One additional condition that shouldn’t be overlooked is one with an interesting name: Legg Calve Perthes Disease.

Legg Calve Perthes Disease: Basics

• Legg Calve Perthes Disease is a Juvenile form of Idiopathic Osteonecrosis of the Femoral Head. [Kim, 2012]

• Incidence = 0.4 – 29 per 100,000 children (<15 years of age) [Loder, 2011]
  • Large range due to discrepancy in definitions and variability between populations.
  • Male:Female = 4:1

• Described in 1909-1910 by Legg (in US), Calve (in France), and Perthes (in Germany).
  • Each postulated a different etiology, but described the same findings. [Wenger, 2011]
  • Today ideas continue to range from traumatic to abnormal osteogenesis to inflammatory to hypercoagulable states to genetic.
  • Some have found associations with high impact sports also. [Georgiadis, 2015]
  • The exact etiology, pathogenesis, and epidemiology is still debated. [Cook, 2014; Kim, 2012]

• While the exact cause is debated, studies do show that the immature femoral head is mechanically weakened following ischemic necrosis. [Kim, 2012]
  • There is an imbalance of bone resorption and new bone formation.
  • The relationship between the femoral head and acetabulum becomes distorted leading to the acetabular rim impinging on the femoral head. [Wenger, 2011]
  • Mechanical weight bearing on the hip leads to further:
    • Deformity
    • Hinge abduction
    • Incongruent joint
    • Premature arthritis

• There are several classification systems – which also points toward persistent controversies. [Kim, 2012; Kuo, 2011; Wenger, 2011]

Legg Calve Perthes Disease: Presentation

• Age at presentation: [Cook, 2015; Loder, 2011]
  • Ranges from 3 – 10 years.
  • Average age = 6.5 years.
  • Children from Indian subcontinent present at average age of 9.5 years.
• Unlike septic arthritis, it is more common in older children.

• Presentation can be similar to other hip pathology and is often on a spectrum of disease.
  • Hip pain
    • Don’t forget about “Knee” or “Thigh” pain as being referred pain from the hip!
  • Limp and antalgic gait
  • Limited range of motion of hip

• Findings that favor Legg Calve Perthes over others (i.e., septic arthritis or synovitis): [Cook, 2015]
  • Onset: weeks – months and may have intermittent episodes reported
    • “Recurrent transient synovitis” should raise your concern.
  • Lack of fever
  • Able to bear weight and may even have normal gait
    • May have a “lurch” or “stiff hip gait”
    • Helps patient avoid using hip flexors while walking.
  • Mild to moderate pain
    • May not even have pain during your exam.
    • NSAIDs often help with pain.
    • “Hip strain” in child? Keep high index of suspicion for other pathology!
  • Pain on flexion and internal rotation.
    • Transient synovitis often has pain at end of range of motion arc.
    • Septic arthritis has severe pain throughout the range of motion arc.

Legg Calve Perthes Disease: Evaluation

• Generally, the best initial testing is with plain radiographs.
• Obtain:
  • AP Pelvis
    • Better than isolated hip film
    • Provides information about sacroiliac joints and pelvis
    • Allows comparison to other hip as well
  • Bilateral frog-leg laterals (AP pelvis with the hips flexed and abducted)

• May have normal film on initial presentation.
• Look for subtle findings:
  • Mild flattening of femoral head compared to other side
  • Loss of epiphyseal height
  • Sclerosis
  • Crescent sign – lucency just under the joint line of the femoral head

Legg Calve Perthes Disease: Management

• Objectives are to: [Kim, 2012]
  • Maintain containment of the femoral head in the acetabulum
  • Maintain good hip range of motion
• Current treatment strategies yield only modest results.
  • Non-operative strategies (ex, bracing, casting) – challenging for patients to use
  • Operative strategies is generally successful, but do have cases of failure. [Nguyen, 2012; Wenger, 2011]
• Not clear that the objectives actually yield improvement in outcomes.

Moral of the Morsel

• There are a number of conditions on the Differential of Limp or Hip/Knee pain.
• Don’t overlook Legg Calve Perthes Disease just because the patient is able to walk.
• Think twice before diagnosing “Recurrent Transient Synovitis” or “Hip Strain.”
• Consider it highly if there is prolonged history of pain or episodic history of pain.
• Most will be managed as outpatient, but early diagnosis and consultation may help maintain hip functionality.

References