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Basics ⬇

Author: ChristopherMcGrew, MD, FACSM, CAQSM

Description

  • Juvenile idiopathic avascular necrosis of the capital femoral epiphysis of the femoral head
  • Synonym(s): Perthes disease; aseptic necrosis of the femoral head; osteochondritis deformans juvenilis; osteonecrosis of capital femoral epiphysis of the femoral head

Epidemiology

  • Incidence in general population 1/1,200 to 1/12,000
  • Prevalence 75/100,000 person-years
  • Predominant age: affects children 3 to 12 yr of age but is most common between the ages of 4 and 9 yr; median age 7 yr
  • Predominant gender: male > female (4 to 5:1)
  • Most prevalent among whites and Chinese; rare in blacks and Native Americans
  • Bilateral hip involvement in 15–20% of patients

Etiology and Pathophysiology

Etiology of Legg-Calvé-Perthes disease (LCPD) is unclear, but the following has been proposed as a theoretical sequence of events (1):

  • Blood supply to the capital femoral epiphysis is interrupted.
  • Bone infarction occurs, especially in the subchondral cortical bone, whereas the articular cartilage continues to grow (articular cartilage receives its nutrients from synovial fluid).
  • Revascularization occurs, and new bone ossification starts. At this point, a percentage of patients develop LCPD, whereas others have normal bone growth and development.
  • LCPD is present when a subchondral fracture occurs. This is the result of normal physical activity, not direct trauma to the area.
  • Changes to the epiphyseal growth plate occur secondary to the subchondral fracture.

Risk-Factors

  • Low birth weight
  • Short stature
  • Delayed bone maturation
  • Involved family member (after index sibling, incidence 1/35)
  • Familial thrombophilia and hypofibrinolysis (controversial)
  • Lower socioeconomic status

Diagnosis ⬆ ⬇

History

Symptoms of LCPD usually have been present for weeks because the child often does not complain:

  • Limp worsened by activity, usually most pronounced at end of day (may be painless)
  • Hip or groin pain, which may be referred to the thigh
  • Mild or intermittent pain in anterior thigh or knee
  • Usually no history of trauma
  • Inflammatory synovitis can mimic LCPD but usually resolves in 10 to 14 days.

Physical Exam

  • Examine the musculoskeletal system with a focus on the pelvis and lower extremities.
  • Include range of motion (ROM) testing to evaluate for limited abduction and internal rotation and the presence or absence of hip flexion contracture.
  • Evaluate for muscle atrophy of the thigh, calf, and buttocks, which may be seen in long-standing cases.
  • Measure for possible leg-length discrepancy, which indicates advanced involvement of the femoral head.
  • Evaluate gait. Trendelenburg gait is observed with abductor weakness.
  • Perform log roll test of extended leg on examining table; painful and reduced ROM is observed compared with the opposite side.
  • Short stature: Children with LCPD often have delayed bone age.

Differential Diagnosis

Diagnostic Tests & Interpretation

  • Anteroposterior and frog-leg lateral views of pelvis; can appear normal early in course
  • Femoral head appears smaller then opposite head with a widened articular cartilage space.
  • With disease progression, a crescent-shaped radiolucent line may be seen in the central portion of the femoral head, especially on the lateral view.
  • Fracture, fragmentation, and resorption
  • Extent of femoral head involvement determines severity of disease. Radiographic changes can be divided into five distinct stages representing a continuum of the disease process, as follows:
    • Stage 1—cessation of femoral epiphyseal growth
    • Stage 2—subchondral fracture
    • Stage 3—resorption
    • Stage 4—reossification
    • Stage 5—healed or residual stage
  • Bone scan and magnetic resonance imaging (MRI) can be used to evaluate and diagnose LCPD before radiographic changes are apparent.
  • MRI may also be used to evaluate disease progression and/or resolution over time if radiographs provide inadequate detail.
  • Ultrasonography is useful to evaluate the presence of synovitis or effusion.

Treatment ⬆ ⬇

General Measures

  • The healing process involves revascularization of the femoral head, removal of necrotic bone, and replacement with viable bone. It is a biologic process that requires many months. No current interventions accelerate this process.
  • Treatment is controversial; goal is to prevent a prearthrotic deformity and subsequent arthritis.
  • Requires individual adaptations and close follow-up
  • Treatment courses vary widely among patients.
  • Nonsurgical treatment:
    • Treatment may involve simple observation, especially in children <6 yr of age.
    • Analgesia: nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen
    • Activity restriction, crutches or wheelchair for non–weight-bearing, and abduction stretching exercises and occasionally bed rest. Abduction bracing/casting can be used for symptom relief and to hold the femoral head in the acetabulum.
    • Casting/bracing may be discontinued when there is radiographic evidence of subchondral reossification, usually after 12 to 18 mo.

Additional Therapies

  • Both surgical and nonsurgical treatments are aimed at symptom reduction, prevention of capital femoral epiphysis destruction, and attainment of a spherical femoral head at healing.
  • Rehabilitation:
    • Formal therapy program is recommended during and after bracing owing to extensive atrophy, contracture, and loss of motion.
    • A home stretching program is encouraged to maintain ROM.

Surgery/Other Procedures

  • Goal is containment of femoral head to maintain or restore joint congruence during the period of biologic plasticity, leading to the restoration of a round femoral head.
  • 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. The two procedures yield equivalent results, but femoral osteotomy may cause shortening of the limb, leading to a chronic limp (2).
  • Techniques vary depending on age of child and severity of femoral head involvement.
  • Advantages include less time required in a brace and earlier return to activity.
  • Disadvantages include necessity of two operations.

Ongoing Care ⬆ ⬇

Follow-up Recommendations

All patients with suspected LCPD should be referred to a pediatric orthopedic surgeon promptly.

Prognosis

  • The younger the age of onset of LCPD, the better is the prognosis.
  • Children >10 yr of age have a very high risk of developing osteoarthritis (3).
  • Most patients have a favorable outcome.
  • Prognosis is proportional to the degree of radiologic involvement as well as later age of onset, obesity, severely limited ROM, and female sex.

Complications

  • Femoral head deformity (i.e., irregular contouring, flattening, or mushrooming of the head and shortening and broadening of the neck) along with flattening of the vertical wall of the acetabulum
  • Degenerative joint disease (onset of severe arthritis varies from adolescence to more commonly in geriatric years)

Additional Reading ⬆ ⬇

  • Ibrahim T, Little DG. The pathogenesis and treatment of Legg-Calvé-Perthes disease. JBJS Rev. 2016;4(7). doi:10.2106/JBJS.RVW.15.00063.
  • Johansson T, Lindblad M, Bladh M, et al. Incidence of Perthes’ disease in children born between 1973 and 1993. Acta Orthop. 2017;88(1):96–100.
  • Leroux J, Abu Amara S, Lechevallier J. Legg-Calvé-Perthes disease. Orthop Traumatol Surg Res. 2018;104(Suppl 1):S107–S112.

References ⬆ ⬇

  1. Berthaume MA, Perry DC, Dobson CA, et al. Skeletal immaturity, rostral sparing, and disparate hip morphologies as biomechanical causes for Legg-Calvé-Perthes’ disease. Clin Anat. 2016;29(6):759–772.
  2. Wiig O, Terjesen T, Svenningsen S. Prognostic factors and outcome of treatment in Perthes’ disease: a prospective study of 368 patients with five-year follow-up. J Bone Joint Surg Br. 2008;90(10):1364–1371.
  3. Heesakkers N, van Kempen R, Feith R, et al. The long-term prognosis of Legg-Calvé-Perthes disease: a historical prospective study with a median follow-up of forty one years. Int Orthop. 2015;39(5):859–863.

Clinical Pearls ⬆

  • Etiology of LCPD is unclear.
  • Treatment courses vary widely among patients, and close follow-up is essential.
  • Both surgical and nonsurgical treatments are aimed at symptom reduction, prevention of capital femoral epiphysis destruction, and attainment of a spherical femoral head at healing.
  • Results of surgical containment appear to be better than those of nonsurgical containment (orthosis) in more advanced cases.