Background: Legg-Calvé-Perthes disease (LCPD) is the name given to idiopathic osteonecrosis of the capital femoral epiphysis of the femoral head. The goal of treatment is to avoid severe degenerative arthritis.

Pathophysiology: The capital femoral epiphysis always is involved. In 15-20% of patients with LCPD, involvement is bilateral.

Mortality/Morbidity:

* LCPD is a self-limited disease if not treated.

* Outcome is extremely variable.

Race: Caucasians are affected more frequently than persons of other races.

Sex: Males are affected 4-5 times more often than females.

Age: LCPD most commonly is seen in persons aged 3-12 years, with a median age of 7 years.

CLINICAL

History: Symptoms usually have been present for weeks because the child often does not complain.

* Hip or groin pain, which may be referred to the thigh

* Mild or intermittent pain in anterior thigh or knee

* Limp

* Usually no history of trauma

Physical:

* Decreased range of motion (ROM), particularly with internal rotation and abduction

* Painful gait

* Atrophy of thigh muscles secondary to disuse

* Muscle spasm

* Leg length inequality due to collapse

* Thigh atrophy: Thigh circumference on the involved side will be smaller than on the unaffected side secondary to disuse.

* Short stature: Children with LCPD often have delayed bone age.

* Roll test

o With patient lying in the supine position, the examiner rolls the hip of the affected extremity into external and internal rotation.

o This test should invoke guarding or spasm, especially with internal rotation.

Causes: The etiology remains unclear; however, the following scenario generally is accepted:

* The blood supply to the capital femoral epiphysis is interrupted.

* Bone infarction occurs, especially in the subchondral cortical bone, while articular cartilage continues to grow. (Articular cartilage grows because its nutrients come from the synovial fluid.)

* Revascularization occurs, and new bone ossification starts.

* At this point, a percentage of patients develop LCPD, while other patients have normal bone growth and development.

* LCPD is present when a subchondral fracture occurs. This is usually the result of normal physical activity, not direct trauma to the area

* Changes to the epiphyseal growth plate occur secondary to the subchondral fracture.

DIFFERENTIALS

Anemia, Sickle Cell
Arthritis, Rheumatoid
Fractures, Pelvic
Hypothyroidism and Myxedema Coma
Pediatrics, Limp
Tuberculosis


Other Problems to be Considered:


Septic hip
Toxic synovitis
Lymphoma
Spondyloepiphyseal dysplasia
Metaphyseal dysplasia
Slipped femoral capital epiphysis

Lab Studies:

* CBC

* Erythrocyte sedimentation rate - May be elevated if infection present

Imaging Studies:

* Plain x-rays of the hip are extremely useful in establishing the diagnosis.

* Frog leg views of the affected hip are very helpful.

* Multiple radiographic classification systems exist, based on the extent of abnormality of the capital femoral epiphysis.

o Waldenstrom, Catterall, Salter and Thompson, and Herring are the 4 most common classification systems.

o No agreement has been reached as to the best classification system.

* Five radiographic stages can be seen by plain x-ray. In sequence, they are as follows:

o Cessation of growth at the capital femoral epiphysis; smaller femoral head epiphysis and widening of articular space on affected side

o Subchondral fracture; linear radiolucency within the femoral head epiphysis

o Resorption of bone

o Re-ossification of new bone

o Healed stage

* Technetium 99 bone scan - Helpful in delineating the extent of avascular changes before they are evident on plain radiographs

* Dynamic arthrography - Assesses sphericity of the head of the femur

Procedures:

* Hip aspiration if a septic joint is suspected

TREATMENT

Emergency Department Care:

* Goals of treatment

o Achieve and maintain ROM

o Relieve weight bearing

o Containment of the femoral epiphysis within the confines of the acetabulum

o Traction

Consultations:

* Once the diagnosis of LCPD is suspected, an orthopedic surgeon or a pediatric orthopedic surgeon should be contacted for further management decisions.

* An orthopedic consultant may choose to order more specialized tests (eg, bone scintigraphy, arthrogram, and magnetic resonance imaging), usually on an outpatient basis, to better determine the extent of the disease.

Medical treatment does not stop or reverse the bony changes. Appropriate analgesic medication should be given.


Drug Category: Nonsteroidal anti-inflammatory drugs (NSAIDs) -- These drugs most commonly are used for the relief of mild to moderately severe pain. Although the effects of NSAIDs in the treatment of pain tend to be patient specific, ibuprofen is usually the drug of choice (DOC) for the initial therapy.

Further Outpatient Care:

* LCPD does not require emergent inpatient care.

* Treatment may involve observation, usually in children younger than 6 years.

* Bed rest and abduction stretching exercises are recommended.

* Nonsurgical containment allows the femoral head to stay within the acetabulum, where it can be molded. Various casts, braces, and crutches have been used for containment.

* Initially, close follow-up is required to determine the extent of necrosis.

* Once the healing phase has been entered, follow-up can be every 6 months.

* Long-term follow-up is necessary to determine the final outcome.

* Surgical correction of gross deformities of the femoral head may be necessary.

Complications:

* LCPD may result in femoral head deformity and degenerative joint disease.

* The femoral head may be distorted permanently.

Prognosis:

* The younger the age of onset of LCPD, the better the prognosis.

* Children older than 10 years have a very high risk of developing osteoarthritis.

* Most patients have a favorable outcome.

* Prognosis is proportional to the degree of radiologic involvement