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Legg-Calvé-Perthes Disease
- Clinical and Radiologic Manifestation -
부산대학교병원 정형외과
김 휘 택
INTRODUCTION
1. LCP disease is an idiopathic osteonecrosis of the
capital femoral epiphysis in children
2. Etiology and management represent a challenge to
orthopaedists
3. It is a significant source of disability in children
EPIDEMIOLOY
1. Common from ages 4 to 8
2. 80% or more of patients are boys (boys : girls =
4 or 5 : 1)
3. 10 to 12% of the patients have bilateral
involvement
4. More common in Asians, Central Europeans
(unusual in blacks, and native Americans)
ETIOLOGY
1. Traditional concept: trauma and inflammation
2. Most current theories concern some disruption of
vascular system
3. Recent research: disorders of clotting system
: Thrombophilia (thrombotic venous occlusion)
- Deficiencies in protein C or S, or resistance to activated
protein C
- Factor-V Leiden mutation and anticardiolipin antibodies
Etiology
4. Systemic factors
1) Delayed skeletal maturity (by about 21 months), but
recovery is possible during later growth
2) Low level of somatomedin C insulin-like growth
factor-1 (IGF1)
3) Hyperactivity or attention deficit disorder
4) Hereditary influences (genetic component)
5) Environmental influences: high occurrence in
particular urban areas (in lower socioeconomic status)
“Unifying“ hypothesis Etiology
Hyperactive child
Minor trauma
Tendency to form clots
Abnormality of
the clot-lysing system
Clotting
in the venous system Venous pressure
rises in the femoral neck
Clotting propagates into
the femoral head
Infarction occurs
1
2
3
4
5
6
7
1. Painless limping – usually first noticed by a
parent
2. Pain in the groin, anterior thigh, or knee
CLINICAL PRESENTATION
PHYSICAL EXAMINATION
1. LOM - primarily IR and ABD
(flexion/extension less affected)
2. Positive Trendelenburg test (thigh, calf,
buttock atrophy)
3. Hip flexion contracture
4. Leg length inequality:
a) adduction contracture
b) collapse of capital femoral epiphysis
• Diagnosis
• Staging
• Provide prognosis
• Follow the course of the disease
• Assess results
1. Radiography: (primary tool )
IMAGING STUDY
Modified Waldenström classification:
(radiographic staging of disease evolution)
1. Initial (AVN) stage
2. Fragmentation stage
3. Reossification (healing) stage
4. Residual stage
Image studies – x-ray
• Widening of the medial joint space (synovitis & hypertrophy of articular cartilage)
• Smaller ossific nucleus (cessation of growth of the capital epiphysis)
1. Initial stage
• Lateralization of the femoral head
• Subchondral fracture
(Waldenström’s sign)
• Metaphyseal lucencies
• Increased density of the femoral
head (accumulation of new bone
on the dead bone trabeculae in the
head
2. Fragmentation stage 3. Reossification stage
4. Residual stage
Gradual remodeling of head shape:
• until skeletal maturity
• acetabulum also remodels
Other radiographic findings
Metaphyseal cyst or lucency (during active disease)
• Poor prognostic value
→ physeal cartilage
extending into the
metaphysis
→ true cyst within the
epiphysis or physis,
metaphysis
Image studies – x-ray
• Radiodense line
overlying the
proximal femoral
metaphysis
• Anterolateral-
inferior protruded
portion of the
femoral head
Image studies – x-ray
“Sagging rope” sign (during healing stage)
• Lateral extrusion of the
capital nucleus
- mushroom head
• Premature physeal
closure with greater
trochanteric overgrowth
Changes in the physis
Image studies – x-ray
Scintigraphy
• Tc 99m bone scan
• Periodic bone scans:
useful for prognosis & to
follow the course of the
disease
Image studies
Arthrography
• Assess the congruity of the
hip in many different
positions
• Most often used in the
early diagnosis of hinge
abduction
Image studies
MRI
• Early Dx.
• Configuration of the
femoral head and
acetabulum
• Revascularization
• Hinge abduction
Image studies
Hinge abduction
Computed tomography
• Not typically used
• Demonstrate 3D images
of the shape of the
femoral head and
acetabulum
Image studies
CLASSIFICATION SYSTEMS (Based on severity of disease)
1. Catterall classification
2. Salter-Thompson classification
3. Lateral pillar classification
An accurate, reliable, and reproducible
classification system is particularly important
in a disorder as variable as LCP.
Group I Group II
Group III Group IV
No metaphyseal reaction No sequestrum No subchondral fracture line
Sequestrum present – junction clear Metaphyseal reaction – antero/lateral Subchondral fracture line – anterior half
Sequestrum – large – junction sclerotic Metaphyseal reaction – diffuse antero/lateral Subchondral fracture line – posterior half
Whole head involvement Metaphyseal reaction – central or diffuse Posterior remodelling
Catterall classification
Catterall classification • Amount of CFE involvement / during the fragmentation stage
Classification
Group I Group II Group III Group IV
CFE
involvement Ant. 25% Up to 50% Up to 75% Entire
Subchondral
Fx. line
No Ant. 1/2 Post. 1/2 Post. margin
Sequestrum No Present
Large
Whole head
Metaphyseal
reaction No Anterolateral Diffuse
anterolateral Central or
diffuse
• Disadvantage
- High degree of interobserver variability
- Not applicable as a therapeutic guide for average of
8 months after onset
Classification
Catterall classification
Salter-Thompson classification
• Based on the extent of the subchondral fracture (initial)
• Group A - less than 50% of the femoral head (good Px)
Group B - more than 50% of the femoral head (poor Px)
Classification
Salter-Thompson classification
• Advantage - good interobserver reliability &
can be applied early in the course of disease
• Disadvantage - not all patients are diagnosed early during
the phase of the subchondral fracture
Classification
Lateral pillar classification
Classification
• Based on the height of the lateral pillar
on an AP view (early fragmentation
stage)
• Intact lateral pillar acts as a weight
bearing support to protect the central
avascular segment
Pillar A
Pillar B
Pillar C
• height maintained
• narrow pillar (2-3 mm)
• little ossification
Pillar B/C border • 50% height
• no collapse of central part
• depressed relative to central pillar
• 50% height
• minimal density of lat. pillar
Herring JA, Kim HT and Browne R:
JBJS Am, 86:2103-2120, 2004.
Lateral pillar classification
Classification
No involvement of the lateral pillar (the best outcome)
Lateral pillar maintains at least 50% of its height
(intermediate outcome)
a) a very narrow pillar (2-3 mm wide) that is >50% of the
original height
b) a lateral pillar with very little ossification but with at least
50% of the original height
c) a lateral pillar with exactly 50% of the original height that
is depressed relative to the central pillar
A loss of more than 50% of the original height of the lateral
pillar (the worst outcome)
Group A
Group B
Group C
Group B/C
border
(new)
PATHOGENESIS OF DEFORMITY
1. Growth disturbance in the CFE and physis
2. Related to the disease process
3. Repair process itself
4. Iatrogenic
LCPD-Pathogenesis of deformity
1
2
3
4
5
1. Growth disturbance in the CFE and physis
Patho. - deformity
Growth plate closure
Hinge abduction • Central arrest
→ short neck (coxa breva)
with trochanteric overgrowth
• Lateral arrest
→ tilts the head externally and
into valgus with trochanteric
overgrowth
2. Related to the disease process
• Superficial layers of articular cartilage:
“overgrow” as they are nourished by the synovial fluid
• Deeper layers : devitalized by the disease process
→ collapse (epiphyseal trabecula) and deformity
Patho. - deformity
3. Repair process itself
• The applied stresses on the femoral head
• Molding action of the acetabulum on the femoral
head
• Deformed femoral head may deform the acetabulum
Patho. - deformity
4. Iatrogenic
• Caused by trying to contain
a non-containable femoral
head (either non-surgically
or surgically)
Patho. - deformity
CLINICAL COURSE (1) 1. Moderate symptoms for 12 to 18 months
2. Starting with early synovitis and/or avascularity with limp
or stiffness of the hip
3. Subchondral bone fracture initiates reactive synovitis,
limiting mobility
4. Muscle spasm (especially, adductors) and weight bearing on
the diseased femoral head cause further subchondral
collapse (femoral head deformity, flattening, and
subluxation)
CLINICAL COURSE (2) 5. Vascular regeneration (creeping substitution) reossifies
the femoral head (often results in hypertrophy)
6. Poorest results are seen in hips with the greatest degree
of involvement
7. Age: before 6 years (mild disease), from 6 to 9 (moderate),
9 or older (the most severe course and worst outcome)
8. Duration: the longer it takes for the hip to heal, the lower
the chance for a good outcome
DIFFERENTIAL DIAGNOSIS
Bilateral changes Unilateral changes
Hypothyroidism Infectious (inflammatory) Ds
Spondyloepiphyseal dysplasia Gauchers Ds
Multiple epiphyseal dysplasia Eosinophilic granuloma
Pseudoachondroplasia Lymphoma
Hemophilia
Bilateral LCP
(Lt. 1.5 years after Rt.)
PROGNOSTIC FACTORS
1) Deformity of the femoral head (hip joint incongruity –
Stulberg classification): the most important prognostic
factor
2) Age at onset of disease: second most significant factor
(whether “older” means older than 6 years, or older than
8 years is subject to debate)
1. Described in Lowell & Winter’s book
Prognostic factors
3) Extent of epiphyseal involvement (the classifications
of Catterall, Salter-Thompson, and Herring)
4) Growth disturbance secondary to premature physeal
closure
5) Protracted course of disease
6) Remodeling potential
7) Type of treatment (?)
8) Stage at initiation of treatment
1) Gage’s sign: a radiolucent V-shaped defect in the
lateral epiphysis and metaphysis
2) Calcification lateral to the epiphysis
3) Metaphyseal lesions
4) Lateral subluxation of the femoral head
5) Horizontal growth plate
2. Radiographic head-at-risk signs (Catterall):
(Causing unexpected poor results)
Prognostic factors
1
1
1. Gage sign: a V-shaped defect
• Deformed FH
• Reversible with Tx
2
2. Lateral
calcification
• Early ossification
• Deformed FH
• Reversible with Tx
2
3
2. calcification
3. metaphyseal change
3. Herald the potential
for growth disturbance
of the physeal plate
2
2
3
2. calcification
3. metaphyseal change
4
5
4. subluxation
5. horizontal
growth plate
4. Widened head
5. Head deformity → hinge abduction
1) Catterall groups III and IV
2) Salter-Thompson group B
3) Lateral pillar group C
4) Lateral pillar group B (> 8 years old)
3. Hips at risk for a poor prognosis
Prognostic factors
4. Clinical at-risk factors
1) Older child
2) Obesity
3) Female sex
4) Marked LOM
Prognostic factors
ANALYSIS OF LATE FEMORAL HEAD DEFOMITIES
functional coxa vara
“sagging rope” sign 변형된 대퇴골두의
전방-하방-외측연에 해당된다.
LCPD-Imaging study (3DCT)
groove on femoral head
Rt. femur의 외회전 Kim HT, Wenger DR: J Pediatr Orthop, 1997.
• upward direction of sourcil
• “sagging rope” sign
Femoro-Acetabular Impingement (FAI)
1. Nonspherical femoral head
2. Narrowed head-neck junction
3. Overcorrected pelvic osteotomy
(localized or generalized acetabular overcoverage)
(retroversion or coxa profunda)
4. Combined extra-articular and intra-articular
impingement
FAI causes damage to the labrum and acetabular cartilage
• FAI: cause of early OA
• Two mechanisms of impingement
1) CAM impingement – nonspherical head
2) PINCER impingement – excessive acetabular cover
CLASSIFICATION OF END RESULTS
• Mose classification
• Stulberg classification
Radiographic result
• Very limited and not cover the myriad possible outcomes
• Fitting contour of the healed
femoral head on the AP & lateral
radiographs (concentric circles)
• Good outcome – 1 mm ↓
Fair outcome – 2 mm ↓
Poor outcome – 2 mm ↑
Mose template
• On the AP film - draw
best fit circle with
center on the
perpendicular line
Circle method
Radiographic result
• On the lateral film - does the same circle fit ?
Stulberg III if not fit within 2mm of circle
>2mm
No
Radiographic result
Stulberg classification
Group I A femoral head that cannot be distinguished from normal
Group II A round femoral head that fits within 2mm of the same circle on
both the AP and the frog-leg lateral radiographs
Group III An ovoid femoral head that does not fit within 2mm of the
circle on one or both views
Group IV A femoral head with at least 1 cm of flattening of the weight-
bearing area on one or both views
Group V A femoral head with collapse, usually central, within a round
acetabulum
• Based on residual femoral head shape
Radiographic result
Stulberg I
Can’t tell which hip
Rt. head larger, round
Stulberg II
Stulberg III
Ovoid head
Flattening
Stulberg IV
Gross incongruity
Stulberg V
Stulberg classification
• Group I and II - good long-term prognosis
• Group III and IV - mild to moderate degenerative
changes in late adulthood
• Group V - painful arthritis in early adulthood
Radiographic result
(Effective in predicting subsequent arthritic changes)
RESULTS OF LONG-TERM FOLLOW-UP (48 YEARS)
1. Most patients developed degenerative joint disease in their
fifties or later
2. 40% (THR), 10% (disabling osteoarthritis)
3. Prevalence of osteoarthritis: 10 times that found in the
general population in the same age range
(48-year follow-up study by McAndrew and Weinstein)
Thank you for your attention!
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