PERTHES' DISEASE - Yorkhill.wscotorth.org.uk

PERTHES’ DISEASE
DAVID SHERLOCK
Royal Hospital for Sick Children
GLASGOW

HISTORY
1909 - Waldenstrom - Sweden
(but thought it was TB)
1910 - Legg USA
- Calve France
- Perthes Germany

Incidence
Wide geographical variation
• 1:1200 in Masschusetts
• 1:5000 in South Wales
• 1:6000 in Scotland
• 1:12500 in England
80% between ages 4 and 9 (range 2-13yrs)
Male to Female 4: 1
10% bilateral

AETIOLOGY
UNKNOWN - no clear genetic cause
CONSTITUTIONAL FACTORS
short stature, average weight, delayed bone age
ENVIRONMENTAL FACTORS
low birth weight, breech presentation, older
parents, poverty
ASSOCIATED ANOMALIES
hernia, undescended testes, renal anomalies,
pyloric stenosis, congenital heart disease

OTHER THEORIES
• Association of Antithrombotic Factor
Deficiencies and Hypofibrinolysis with
Legg-Perthes’ Disease.
Glueck et al JBJS(1996)78A 3-13
• Not confirmed in other centres including
Glasgow
Jobanputra et al. Brit Soc Haem (2000)44 80

MY THEORY
• GENETIC
- delayed bone age
• CONSTITUTIONAL
- high pain threshold
- hyperactive or overweight child
Extent of each component may vary
between children

PATHOLOGY
• Infarction of capital femoral epiphysis,
partial or total
• Infarction is often sequential
• Repair occurs by creeping substitution with
removal of necrotic bone and its
replacement with new bone or fibrocartilage
• Cartilage nourished by synovial fluid so still
lives, but deforms as bone collapses

PROCESS OF DEFORMITY
The head changes from a sphere to oval as a
result of collapse and lateral overgrowth.
Secondary acetabular remodeling occurs
but the acetabulum remains dysplastic.
This converts the ball & socket to a roller
bearing joint with its movement axis from
extension/adduction to flexion/abduction.

PROGNOSTIC INDICATORS
WHY DO WE NEED THEM?
• Avoids over-treating children who will
do well whatever or who are too late
for treatment to alter the outcome
• Avoids under-treating those who may
get benefit

PROGNOSTIC INDICATORS
• Age
• Extent of head involvement
• (Sex)
• Phase of the disease
• Lateral subluxation
• Physeal growth disturbance
• Metaphyseal changes
• Stiff hip
• Obese child

AGE
In younger children
• Physeal damage occurs less
frequently
• Longer period for remodelling

EXTENT OF INVOLVEMENT
• Catteral classification
• Salter/Thomson classification
• Herring classification
• Arthrographic assessment of
sphericity (Macnicol)

CATTERALL
CLASSIFICATION
• Initial description very complicated. Easiest
to consider as 1/2 head
involvement
• Initial changes seen anterior -> posterior
• Considerable inter- & intra-observer
variability for critical Gp 2/3 divide
• By time class is clear it may be too late to
alter outcome

CATTERAL GROUP 1

CATTERALL GROUP2

CATTERALL GROUP 3

CATTERALL GROUP 4

SALTER-THOMSON
CLASSIFICATION
Assess on AP & Frog lateral X-rays
A: Subchondral fracture of< half head
B: Subchondral fracture of> half head
BUT subchondral fracture only visible
in 15% of cases

SALTER-THOMSON
Subchondral Fracture

HERRING CLASSIFICATION
Assess height of lateral pillar on AP X-
ray in fragmentation phase
A: Normal lateral pillar
B: Pillar height 50-100%
C: Pillar height less than 50%

ARTHROGRAPHIC GRADING
Ismail & Macnicol JBJS 80B, 1998
• Spherical
- no loss of contour in 4 views
• Mild Deformity
- loss in 1 view
• Moderate Deformity - loss in 2 views
• Severe Deformity
- loss in 3 or 4 views

ARTHROGRAPHIC GRADING

SEX
• Females seem to get more serious
form of Perthes’ Disease
• Females may have less time to
remodel since growth finishes
earlier

PHASE AT DIAGNOSIS
• Starting treatment before onset of deformity
maximizes chance of good outcome
• Deformity once present cannot be reversed
• Maintain treatment till head strong enough
to resist loads ie. in healing phase

PHASE OF ONSET
Infarction causes a growth arrest of
the bony epiphysis but the
articular cartilage continues to
grow. This gives the appearance of
widening of the infero-medial joint
space

PHASE OF SCLEROSIS
The femoral head becomes more dense
due to trabecular fracture, appositional
new bone formation and calcification
of the necrotic bone marrow
Disuse osteoporosis in the adjacent live
bone heightens the sclerotic
appearance

PHASE OF SCLEROSIS

FRAGMENTATION PHASE
Repair by creeping substitution causes
the appearance of fragmentation on X-
ray
Repair in thickened articular cartilage
occurs by endochondral ossification: in
the antero-lateral cartilage this gives
the “calcification lateral to the
epiphysis” sign of the “head at risk”

FRAGMENTATION PHASE

PHASE OF HEALING
Necrotic bone is now largely
replaced by new bone but the
femoral head is deformed with
widening of the femoral neck
(Coxa Magna) and flattening of the
head (Coxa Plana)

PHASE OF HEALING

DEFINITIVE PHASE
With healing complete the final
position is now clear
A poor result will show Coxa
Magna and Plana with lateral
subluxation and overgrowth of the
trochanter

SIGNS OF HEAD AT RISK
• CLINICAL
Stiff hip, Obesity, Adduction contracture
• RADIOLOGICAL
Gage’s sign, calcification lateral to the
epiphysis, lateral subluxation, diffuse
metaphyseal changes

SIGNS OF HEAD AT RISK

PROGNOSIS
• 85% develop OA by age 65
• Most do not develop symptoms till 40’s
• 1/3 improve after healing
• 9% get worse requiring THR by age 35
These children often have late onset Perthes
resulting in an irregular uncovered head
with partial growth arrest and a stiff hip

DIFFERENTIAL DIAGNOSIS
UNILATERAL
• Infection
• Gaucher’s Disease
• Haemophilia
• Eosinophilic
Granuloma
• Lymphoma
BILATERAL
• MED
• SED
• Hypothyroidism

TREATMENT PRINCIPLES
• Don’t over-treat children who will do well
anyway
• Restore Movement
• Relieve Stress in Femoral Head
• Contain Femoral Head
• Prevent further Ischaemia

TREATMENT
Hip Abduction reduces forces through
the hip, restores lost movement and repositions
the uncovered antero-lateral
part of the femoral head within the remodelling
influence of the acetabulum
ie. Containment

TREATMENT OF EARLY
PHASES
• Diagnosis, Assessment, Arthrography
• Containment & Mobilization of Hip
• Maintain Containment & Movement
till Healing is established

Maintain containment till healing
established
• Conservative- Retain POP 1-2 years
• Operative
- Age8 Shelf procedure

WHAT I DO
• Age8 Arthrogram, Staheli Shelf

Arthrogram showing minor
deformity

Adjustable Abduction Bar

Varus Osteotomy

Shelf Procedure

FINAL OUTCOME
Stulberg Classification 1981
1 Normal
2 Spherical with Coxa Magna or neck change
3 Non-spherical head with acetabular changes
4 Flat head but congruent with acetabulum
5 Flat head non congruent with acetabulum

Outcome for Perthes in children
under 8 at presentation
• 14 pairs of patients (28 hips) matched for
sex, body mass index, age & phase of
disease at onset degree of head involvement
and at risk signs were abstracted from 345
children with Perthes on our database.
• 5 radiological outcome measures (Mose,
Stulberg, acetabulum-head index,
acetabular roof slope & articulotrochanteric
distance.

Methods
• Radiological outcomes compared for
POP versus surgical treatments
• Surgery comprised varus osteotomy
(8), shelf procedure (5) & Salter
osteotomy (1)
• POP for 7 to 19 months

Results
• 9 Catterall III, 5 IV; 5 Herring B, 9 C.
• All had initial subluxation
• 12 male pairs; 2 female pairs
• No difference in outcome for Stulberg, AHI
& ATD
• Mose 1 grade better for surgery versus POP
• AHI better for shelf procedure but not for
varus osteotomy/ Salter versus POP

Conclusion
• Only difference in outcome for POP versus
surgery treatment was for Mose by 1 grade
(unclear if applies to all surgery or shelf
only) – see after
• Applies to severe Perthes with > half head
involvement & subluxation
• Fits with Herring who found outcome in

Outcome for Perthes in
children over 8 at presentation
Four treatment groups
• No treatment (presented too late)
• Abduction POP till evidence of healing
• Varus osteotomy
• Shelf procedure

Methods
• 44 children (48 hips)
• Followed to maturity in cohort study
• Catterall grades II, III, IV
• Groups demographically similar
• Outcomes assessed by Stulberg, Mose,
% head cover & CEA.

Results
• Over all groups 60% Stulberg 1 to 3
• Poorer outcome (Stulberg, Reimers, CEA)
with increasing age, greater initial head
deformity & more head involvement.
• Initial head deformity did not remodel for
any group
• Deformity increased in POP & varus
osteotomy groups. Static for shelf group.

Conclusion
• Shelf procedure gave better
outcome for Stulberg, Reimer’s
index, CEA & head deformity
than observation or treatment
by POP or varus osteotomy

TREATMENT OF LATE
PRESENTATION
If an Arthrogram shows HINGE
ABDUCTION then a VALGUS
OSTEOTOMY will relieve the
pain of impingement and reduce
leg shortening

Valgus Osteotomy

Profile of Perthes’ in Glasgow
• Burwell et al (1978) suggested link between
Perthes’ & other congenital anomalies
• Barker et al (1983) suggested that poverty
was linked to Perthes’
• Harper et al (1976) found only a minor
genetic component in Perthes’

RHSC PERTHES’ DATABASE
1990-2003
• Total number Perthes’ patients 422
• DAS Perthes’ patients 246
• Demographic details collected for these
patients

GENDER

LATERALITY

MEAN AGE AT DIAGNOSIS 5.9 YEARS
Range 2-12.5. 43%

THANK YOU