Legg Calve Perthes Disease

History• FIRST DESCRIBED

BY LEGG AND WALDENSTORM IN 1909 AND BY PERTHES ANDCALVE IN 1910

Definition• Legg-Calvé-Perthes

disease (LCPD) is the name given to idiopathic osteonecrosis of the capital femoral epiphysis in a child.

Epidemiology• Disorder of the hip in young children• Usually ages 4-8yo• As early as 2yo, as late as teens• Boys:Girls= 4-5:1• Bilateral 10-12%• No evidence of inheritance

• Prevalence:

77.4%

6.0%2.8%5.3%8.5%

Transientsynovitis

SCFE

Infection

Perthes'disease

Other

Etiology• Unknown• Past theories: infection, inflammation,

trauma, congenital• Most current theories involve vascular

compromise▫Sanches 1973: “second infarction theory”

Causes• Proposed theories.

▫Excessive femoral antiversion.▫Synovitis.▫Generalized skeletal disorder.▫Arterial anomalies.

Pathogenesis• Histologic changes described by 1913• Secondary ossification center= covered by

cartilage of 3 zones:▫Superficial▫Epiphyseal▫Thin cartilage zone

• Capillaries penetrate thin zone from below

• Epiphyseal cartilage in LCP disease:▫Superficial zone is normal but thickened▫Middle zone has

1) areas of extreme hypercellularity in clusters and 2) areas of loose fibrocartilaginous matrix

• Superficial and middle layers nourished by synovial fluid

• Deep layer relies on blood supply

• Physeal plate: cleft formation, amorphis debris, blood extravasation

• Metaphyseal region: normal bone separated by cartilaginous matrix

• Epiphyseal changes can be seen also in greater trochanter, acetabulum

Blood Supply

Radiographic Stages• Four Waldenstrom stages:

▫1) Initial stage▫2) Fragmentation stage▫3) Reossification stage▫4) Healed stage

Initial Stage• Early radiographic signs:

▫Failure of femoral ossific nucleus to grow▫Widening of medial joint space▫“Crescent sign”▫Irregular physeal plate▫Blurry/ radiolucent metaphysis

Fragmentation Stage• Bony epiphysis begins to fragment• Areas of increased lucency and density• Evidence of repair aspects of disease

Reossification Stage

•Normal bone density returns•Alterations in shape of femoral head and

neck evident

Healed Stage• Left with residual deformity from disease and

repair process• Differs from AVN following Fx or dislocation

Group I

Group II

Group III

Group IV

Lateral Pillar Classification• 3 groups:

▫A) no lateral pillar involvment

▫B) >50% lat height intact

▫C) <50% lat height intact

Salter-Thompson Classification• Simplification of Catterall• Based on status of lateral margin of capital

femoral epiphysis• Group A (Catterall I & II equivalent)• Group B (Catterall III & IV equivalent)

Clinical Features• Stature usually shorter than peers• Quadriceps and gluteal muscle wasting is

common, Trandelenburg test positive (drop of the hip on the unsupported side)

• Acute phase; range of motion at the hip joint is limited due to muscle spasms

• Progressively; limited internal rotation and abduction is likely due to impingement lesions (hence the Roll test, guarding on affected side)

• Later stage; global reduction in all ranges of motion assoc. with pain, indicating joint arthritis

• Age- 4 to 10 years, with peak incidence at 7• Gender- Boys (5:1 ratio) but it tends to be more

severe in girls• Height• Passive smoking or maternal smoking at pregnancy• ADHD? Increased physical activity• Family Hx of; skeletal dysplasias or thrombotic

disease• Ethnicity; more common in Whites, Eskimos,

Japanese• Social Hx- associated with low socio-economic status

Risk Factors

Differential Diagnosis

Workup• Technetium 99 bone scan -

Helpful in delineating the extent of avascular changes before they are evident on plain radiographs.

▫The sensitivity of radionuclide scanning in the diagnosis of LPD is 98%, and the specificity is 95%.

• Dynamic arthrography - Assesses sphericity of the head of the femur.

• Ultrasonography may provide significant diagnostic clues to differentiate early Perthes' from transient synovitis.

T Futami, Y Kasahara, S Suzuki, S Ushikubo and T Tsuchiya Journal of Bone and Joint Surgery - British Volume, Vol 73-B, Issue 4, 635-

639

Ultrasonography in transient synvitis and early Perthes’ disease

CT Scan

• Staging determined by using plain radiographic findings is upgraded in 30% of patients.

• Not as sensitive as nuclear medicine or MRI.

• CT may be used for follow-up imaging in patients with LPD.

MRI• It allows more precise

localization of involvement than conventional radiography.

• MRI is preferred for evaluating the position, form, and size of the femoral head and surrounding soft tissues.

• MRI is as sensitive as isotopic bone scanning.

Outcome variables

• Age

• Extent of involvement

• Duration

• Remodeling potential

• Premature physeal closure

• Type of treatment

• Stage of disease at treatment.

Treatment Options

Overall goal of treatment1.Reduce hip irritability and pain2.Restore/maintain hip mobility3.Prevent femoral head from extruding or

collapsing “CONTAINMENT”4.Regain spherical shape of femoral head

Below 6 years and Herring A/B• Mainstay of treatment would be to OBSERVE

with 6-12 month reassessment.• Patients in this age group need bed rest and

anti inflammatory medication at most. NO evidence that abduction splints or surgery beneficial

• Prognosis is good for the majority

Non Surgical treatment1.NSAIDS2.Traction3.Casts and braces (Scottish Rite Orthosis)

Above 6 and Herring class B• Containment of the head within the

acetabulum is warranted

This is achieved by;• Abduction bracing• Femoral varus osteotomy• Pelvic ostotomy

Age between 6-8 and Herring class C• Results of intervention have been equivocal.

• Above 9 years1.Often have Herring class B or C2.Prognosis is poor3.Early containment is key, by pelvic

osteotomy and internal fixation

Osteotomies

Summary• For patients less that 6 years old the

prognosis is good for the majority. • If they are stiff or painful they respond to

bed rest, traction and pain relieving anti-inflammatory medication.

• There is no evidence that abduction splints or surgical intervention is warranted in the majority of these younger patients.

• For patients between 6 and 8 years but with a bone age less than 6 and an intact lateral pillar (Herring A and B) the prognosis is similar to that for the first group and observation is as good as surgical intervention for the majority.

• If they have bone ages greater than 6 years and Herring lateral pillar classification B then "containment" of the head within the acetabulum seems to be warranted.

• This may be done by abduction bracing, femoral varus osteotomy or a pelvic osteotomy.

• If they are between 6 and 8 and are in lateral pillar group C then the result of intervention are equivocal.

• Children presenting with Perthes disease at age 9 or older often have lateral pillar B or C and a poor prognosis.

• The trend is towards early containment of these hips although stiffness can be a problem following early pelvic (Salter's) osteotomy.

Follow-up• 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.

Complications

Femoral ▫Shortening▫stiffness▫Malrotation▫Limp▫Positive

trendelenburg

Pelvic▫Lenghtening▫Stiffness▫Chondrolysis▫Failure of

containment

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.