Legg–Calvé–Perthes Disease — Classification, Head-at-Risk Signs and Management
DNB Orthopaedics • May 2024 • Paper II • 10 Marks
Introduction
Legg–Calvé–Perthes disease (LCPD) is an idiopathic, self-limiting childhood disorder characterized by temporary interruption of the blood supply to the capital femoral epiphysis, resulting in osteonecrosis of the femoral head, followed by resorption, revascularization, reossification and eventual healing.
It most commonly affects children between approximately 4 and 8 years of age, is more common in boys, and is usually unilateral. Bilateral involvement occurs in a minority of patients and is often asynchronous.
Central principle: The femoral head is biologically capable of healing; treatment aims to keep it spherical and well contained inside the acetabulum while this healing occurs.
Pathophysiology
Temporary interruption of epiphyseal blood supply
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Osteonecrosis of capital femoral epiphysis
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Subchondral weakening
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Mechanical loading of weak head
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Flattening / extrusion / fragmentation
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Revascularization and resorption
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New bone formation
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Reossification and remodeling
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Final femoral-head shape determines long-term prognosis
The major mechanical danger is lateral extrusion of the softened femoral head. Once the head extrudes outside the acetabular mould, progressive flattening and asphericity may occur.
Etiology and Associations
The exact cause remains…