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Musculoskeletal System ORGAN SYSTEMS

Legg–Calvé–Perthes disease (LCPD)

Introduction

Perthes disease (Legg-Calvé-Perthes disease) is an idiopathic osteonecrosis/avascular necrosis of capital femoral epiphysis of the femoral head.

  • Type of aseptic osteochondroses of childhood
  • :::4:1, typically in 3-7 years

History

The disease was described nearly simultaneously in the year 1910 by G. C. Perthes in Germany, A. T. Legg in the United States, and J. Calvé in France.


Aetiology

Clinical risk factors for a poor outcome:

  • Later age of onset
  • Overweight
  • Severe limitation of the range of motion
  • Female sex

Pathophysiology

Avascular necrosis of the epiphysis

Impairs enchondral ossification of femoral head

Stages of Legg-Calves-Perthes (Waldenström):

  • Initial stage:
    • Infarction produces a smaller, sclerotic epiphysis with medial joint space widening
  • Fragmentation stage:
    • Result of revascularization process with bone resorption producing collapse with subsequent patchy density and lucencies
    • Radiological findings:
      • Begins with presence of subchondral lucent line (crescent sign)
      • Femoral head appears to fragment/dissolve
    • Lateral pillar classification based on this stage
  • Reconstitution stage:
    • Ossific nucleus undergoes reossification with new bone appearing as necrotic bone is resorbed
  • Healed stage:
    • Femoral head remodels until skeletal maturity 
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The stages of evolution of Perthes’ disease. The early part of the disease is from the onset till Stage IIa (early fragmentation stage). The late part of the disease is from Stage IIb to Stage IIIb. Intervention aimed at preventing femoral head deformation is only feasible during the early part of the disease | Joseph, B. (2015). Management of Perthes’ disease. Indian Journal of Orthopaedics, 49(1), 10–16. https://doi.org/10.4103/0019-5413.143906

Clinical features

  • Hip/groin pain
    • Present during physical activity
    • Radiates to thigh & knee (25% cases)
    • Bilateral (asymmetrical, asynchronous involvement) (10-15% cases)
  • Limping gait
  • Different length of legs (due to adduction contracture or collapsed epiphysis)

Diagnosis

Imaging

X-ray:

  • Pelvic survey film and lateral hip x-ray:
    • Establish diagnosis
    • Enable classification, prognostic assessment, and follow-up of the course of the disease
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AP and frog lateral radiographs prototypical of the presentation of female Perthes disease, with femoral head fragmentation and loss of height of the lateral pillar | Georgiadis, A. G., Seeley, M. A., Yellin, J. L., & Sankar, W. N. (2015). The presentation of Legg-Calvé-Perthes disease in females. Journal of Children’s Orthopaedics, 9(4), 243–247. https://doi.org/10.1007/s11832-015-0671-y
  • Head-at-risk signs (1971, Catterall):
    • Gage sign (V-shaped radiolucency in the lateral portion of the epiphysis and/or adjacent metaphysis
    • Lateral epiphyseal calcification
    • Lateral subluxation of the femoral head
    • Horizontal proximal femoral physis
    • Metaphyseal cyst (added later to the original 4 at-risk signs described by Catterall)
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Involvement of the entire epiphysis, with the height of the lateral pillar less than half normal (Herring type C, Catterall type IV). In addition, note lateralization (arrow) and metaphyseal cysts, both of which are “head-at-risk” signs. | Nelitz, M., Lippacher, S., Krauspe, R., & Reichel, H. (2009). Perthes disease: current principles of diagnosis and treatment. Deutsches Arzteblatt International, 106(31–32), 517–523. https://doi.org/10.3238/arztebl.2009.0517

Ultrasonography (USG):

  • Supplementary technique to diagnose changes of the femoral head and, in particular, any accompanying synovitis or effusion

Magnetic resonance imaging (MRI):

  • Identifying the early stage of Perthes disease in the absence of changes on plain films, as well as in cases where the differential diagnosis would otherwise be difficult.
  • Dynamic MRI (eg. arthrography): Diagnosing any accompanying “hinge abduction” (lateral side of the femoral head contacts the acetabular margin) during preoperative planning

Prognostic classification

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Herring’s “lateral pillar” classification, depending on the height of the lateral pillar (necrotic area marked in red) | Nelitz, M., Lippacher, S., Krauspe, R., & Reichel, H. (2009). Perthes disease: current principles of diagnosis and treatment. Deutsches Arzteblatt International, 106(31–32), 517–523. https://doi.org/10.3238/arztebl.2009.0517
Lateral Pillar (Herring) Classification
Group A  Lateral pillar maintains full height with no density changes identified
Group B  Lateral pillar >50% height
B/C Border Lateral pillar narrowed (2-3mm) or poorly ossified with approximately 50% height
Group C  Lateral pillar <50%

Differential diagnosis

  • Coxitis fugax
  • Juvenile idiopathic arthritis (JIA)
  • Osteomyelitis
  • Meyer’s dysplasia
    • Absence of clinical symptoms and of the staged radiological progression that typifies Perthes disease
  • Epiphyseal dysplasia
  • Spondyloepiphyseal dysplasia
  • Chondroblastoma
  • So-called “Perthes” due to hip dysplasia
  • Cortisone-induced necrosis of the femoral head

Management

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Treatment algorithm for Perthes disease, depending on the patient’s age and risk factors | Nelitz, M., Lippacher, S., Krauspe, R., & Reichel, H. (2009). Perthes disease: current principles of diagnosis and treatment. Deutsches Arzteblatt International, 106(31–32), 517–523. https://doi.org/10.3238/arztebl.2009.0517

Goals of treatment:

  • Improved mobility
  • Reduction of mechanical stress
  • Preservation of joint congruence (containment)

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