Practice Essentials
Legg-Calvé-Perthes disease (LCPD) is avascular necrosis (AVN) of the proximal femoral head resulting from compromise of the tenuous blood supply to this area. [1] LCPD usually occurs in children aged 4-10 years. The disease has an insidious onset and may occur after an injury to the hip. In the vast majority of instances, the disorder is unilateral. Both hips are involved in fewer than 10% of cases, and the joints are involved successively, not simultaneously.
The earliest sign of is an intermittent limp (abductor lurch), especially after exertion, with mild or intermittent pain in the anterior part of the thigh. Hip pain may develop and is a result of necrosis of the involved bone. Pain may be present with passive range of motion and limited hip movement, especially internal rotation and abduction. Children with LCPD can have a Trendelenburg gait resulting from pain in the gluteus medius.
Initial therapy includes minimal weightbearing and protection of the joint. (See Treatment.) Results of surgical containment appear to be better than those of nonsurgical containment (orthosis). Surgical management typically involves either femoral osteotomy to redirect the involved portion within the acetabulum or innominate osteotomy.
For patient education resources, see the First Aid and Injuries Center, as well as Repetitive Motion Injuries.
Pathophysiology
Rapid growth occurs in relation to development of the blood supply of the secondary ossification centers in the epiphyses, causing interruption of adequate blood flow and making these areas prone to AVN. Interruption of the blood supply to the bone results in necrosis, removal of the necrotic tissue, and its replacement with new bone.
Bone replacement may be so complete and perfect that completely normal bone may result. The adequacy of bone replacement depends on the age of the patient, the presence of associated infection, the congruity of the involved joint, and other mechanical and physiologic factors. Necrosis may occur after trauma or infection, but idiopathic lesions can develop during periods of rapid growth of the epiphyses.
Etiology
The cause is not known, but children with LCPD have delayed bone age, disproportionate growth, and a mildly shortened stature. LCPD may be idiopathic, or it may result from a slipped capital femoral epiphysis, trauma, steroid use, sickle-cell crisis, toxic synovitis, or congenital dislocation of the hip.
Epidemiology
LCPD usually occurs in children aged 4-10 years (mean age, 7 years). It occurs more commonly in boys than in girls (male-to-female ratio, 4:1). The condition is rare, occurring in approximately 4 of 100,000 children. A British study reported an incidence of 2.8 per 100,000 persons aged 14 years or younger. [2]
A population-based design study demonstrated that patients with a history of LCPD seem to have a higher risk of severe injury than those without the disease. This risk may be due to a tendency for more hyperactive behavior among LCPD patients, especially females. [3]
Prognosis
The prognosis for patients with LCPD can be good; it depends on the completeness of involvement of the epiphyseal center. The severity of involvement of the femoral head, its subsequent healing, and proper joint space preservation all help determine when and to what degree an athlete will be able to participate in sports. The functional result depends on the amount of deformity that develops when the structure is softened. Overall, the prognosis for recovery and sports participation after treatment is very good for most individuals.
The short-term prognosis is related to femoral head deformity at the completion of the healing stage. Risk factors include the following:
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Clinical onset at an older age
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Extensive femoral epiphyseal involvement
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Femoral head containment
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Reduced range of motion in the hip
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Premature closure of the growth plate
The long-term prognosis is related to the potential for osteoarthritis of the hip as an adult. [4] It is worse for patients with metaphyseal defects, those in whom the disease develops late in childhood (age ≥10 years), and those who have more complex involvement of the femoral head with residual deformity; degenerative arthritis occurs in nearly 100% of these patients. This rate is in comparison to patients who are younger than 5 years when the problem develops; the incidence of degenerative arthritis is negligible in this younger population.
The results of one small retrospective study found that total hip replacement can be considered a possible option for patients who had LCPD in childhood. Alhough a high rate of neurologic complications was noted, these were possibly related to inadequate soft-tissue release or excessive limb-lengthening. [5]
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Image from 8-year-old boy with Herring type C Legg-Calvé-Perthes disease shows evidence of lateral extrusion. Symptoms began 18 months before this view was obtained. Image courtesy of Dennis P Grogan, MD.
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Anteroposterior radiograph from 9-year-old boy with Legg-Calvé-Perthes disease. Image courtesy of Dennis P Grogan, MD.
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Frog-leg lateral radiograph of same 9-year-old boy with Legg-Calvé-Perthes disease as in previous radiograph. Image courtesy of Dennis P Grogan, MD.
