Pathophysiology and management of Legg Calve Perthes disease

1. Legg – Calve – Perthes
Disease
Dr. Ahmed Azim
2nd year resident
TUTH

2. • Disease of children caused by idiopathic ischemic necrosis of femoral
capital epiphysis which may vary in degree and severity
• Following avascular necrosis reossification always occurs
• Leads to permanent femoral head deformity and premature
osteoarthritis

3. Legg – Calve - Perthes
Arthur T. Legg
1874-1939
Jacques Calve
1875-1954
Georg C. Perthes
1869-1927
Henning Waldenstrom

4. Even after 100 years
•Perthes disease remains an enigma shrouded in
controversy

5. Good news!!
• Half the patients will recover and have little disability over their
lifetime
• The other half will function well with occasional discomfort through
most of their adulthood and in their 5th or 6th decade of life require
hip replacement
• Only the most severely involved patients will have early hip disability
Herring JA 1996; Weinstein SL, 1985

6. Applied anatomy
• Blood supply of head
• Upto age 4 mo
1. Metaphyseal vessels penetrate physis
2. Lateral epiphyseal retinacular vessels
3. Scanty vessels in ligamentum teres

7. • Metaphyseal supply gradually
decrease (disappears by 4 yrs)
• Vessels of ligamentum teres
developed by 7 yrs
• 4 yrs – 7yrs blood supply depend
entirely on lateral epiphyseal
vessels

8. Epidemiology
• Incidence: 1 : 10,000
• Usual Age: 4 – 10 yrs
• Male:Female = 4:1
• Billateral in 10-15%
• May be part of general growth disorder
• Higher incidence in underprivileged (UK epidemiologic study)

9. Etiology
• Exact cause unknown
• Affected children: small & delayed maturation
Various theories proposed
• Trauma
• An inflammatory process
• Vascular occlusion
• Thrombophilia
• Insulin-like growth factor-1 pathway abnormality
• Maternal smoking & second-hand smoke exposure
• Type-II collagen mutation

10. Etiology
Prevailing Opinion Is That Legg-calvé-perthes
Disease Is A Multifactorial Disease With Genetic
And Environmental Factors Playing A Role

11. Etiology
Associated features
• Low birth weight
• Breech delivery
• Short stature
• Irritable hip
• Disproportionate growth
• ADHD
• Older parents
• Parents often relate to a trauma
• Genetic predisposition
• Coagulation disorders

12. Pathology
• Disruption of blood supply to the femoral head, is one of the key
pathogenic event
1. Microtrauma to retinacular vessels
2. Increased synovial pressure
eg: Transient synovitis
3. Venous HTN 2⁰ to thrombotic occlusion
• Single ischemic episode vs. multiple ischemic events

13. Pathogenesis & pathology
• Repeated bouts of ischaemia & infarction of femoral head →
pathologic fractures
• Retinacula vessels susceptible to stretching & pressure from effusion
• Increased pressure cause venous stasis
• Increase in intraosseous pressure
• Ischaemia & infarction leading to necrosis

14. Pathogenesis of femoral head deformity
• Pathogenesis of the femoral head deformity following ischemic necrosis is
complex
• Multiple factors contribute to the development of the deformity
1. Mechanical properties of the articular cartilage and the bone are
decreased
• Necrosis of the deep layer of the articular cartilage
• Inability of the necrotic bone to repair microdamage
• Increase in the calcium content of the calcified cartilage and the
subchondral bone making it brittle
• When mechanical loading > strength of bone = subchondral fractures &
collapse

15. Pathogenesis of femoral head deformity
2. Pathological repair process
• Predominance of osteoclastic resorption
• Delayed bone formation
• replacement of the necrotic bone by a fibrovascular granulation tissue
3. Growth arrest of the spherical growth plate
• Restoration of growth in asymmetrical manner

16. Pathogenesis & pathology

17. A flowchart depicting the pathogenesis of the femoral head deformity in Legg-Calvé-Perthes disease.
Harry K.W. Kim J Bone Joint Surg Am 2012;94:659-669

18. Clinical features
• Typically a boy of 4-8 years who has high physical activity
• Smaller than his counterparts
• C/O pain & limping
• Maybe painless limp
• Pain may radiate to knee
• Aggravated by strenuous activity & relieved by rest
• Continuous for weeks or intermittent
• Urogenital anomaly in 4%

19. Clinical features
• Leg length discrepancy
• Mild muscle wasting
• ROM
• Early: joint irritable, decreased ROM & painful in extremes
• Later: Movements full except abduction & IR
• Maybe flexion / adduction contracture
• Gait: Antaalgic or Trendelenburg / Abductor gait
• Trendelenburg test: +ve

20. Diagnosis
• Based on clinical features & Radiology
• Investigations:
• Routine blood investigation
• X-ray
• Initially normal
• Subtle changes: widening of joint space, asymmetry
of ossific centres
• Necrotic phase: Increased density of ossific nucleus
• Fragmentation phase: Alternating patches of
density & lucency
• Crescent sign (best seen on lateral view)
• Re-ossification phase: Increased epiphyseal density

21. Diagnosis
• MRI:
• Evidence of marrow necrosis
• Irregularity of the femoral head,
• Loss of the signal on the affected
side

22. Diagnosis
• Bone scan:
• reduced uptake early in the disease
• Ultrasound
• Joint effusion
• Arthrography: To see congruity, head deformity

23. Classification: Waldenstrom
Stage 1: Initial
phase
• All or part of nucleus dead. Maybe normal X-ray. Increased density of
epiphysis,
• Cartilage thickening, subtle lateral subluxation via increased medial
cartilage growth (Waldenstrom’s sign)
• Subcondral # (Crescent sign)
• Duration: 6 months
Stage 2:
Fragmentation
phase
• Areas of lucency and sclerosis
• Central area separates from lateral & medial areas
• Maximal flattening/collapse
• Duration: 8 months
Stage 3:
Reossification
phase
• New subchondral bone formation
• Flattening may improve
• Duration: 3-5 years
Stage 4: Residual
phase
• No change in bone density
• Shape of head changes
• Final shape after skeletal maturity
• Acetabular remodelling

24. Classification: Modified Waldenstrom

25. Classification: Modified Waldenstrom

26. Classification
• Catterall classification (1982)
• Group I: Normal height of epiphysis & <50%of head
involved
• Group II: ½ of neucleus sclerotic & collapse of central
portion
• Group III: Most of the neucleus involved, fragmentation &
collapse. Metaphyseal resorption maybe present
• Group IV: Whole head, Ossific neucleus is flat & dense,
marked metaphyseal resorption

27. Classification
• Catterall classification (1982)
• Head at risk signs:
1. Lateral subluxation
2. Speckled calcification lateral to the
capital epiphysis
3. Diffuse metaphyseal reaction
(metaphyseal cysts)
4. A horizontal physis
5. The gage sign, a radiolucent v-shaped
defect in the lateral epiphysis and
adjacent metaphysis

28. Classification
• Herring classification
• Greater predictive
value of outcome
• Based on height of
lateral pillar

29. Classification
• Herring classification
• LCPD study group Herring, Kim & Browne
JBJS 2004;86:2121-2134
• 28 institutions: uniform method of treatment
• 345 hips all over age of 6
• Followed till maturity

30. Classification
• Herring classification
• LCPD study group Herring, Kim & Browne
JBJS 2004;86:2121-2134
• Herring A: All do well without any treatment
• Herring B: Bone age <8 : Uniform outcome irrespective treatment
• Herring B: Bone age>8: Surgery (Femoral/Salter) > Brace > No treatment
• Herring C: Bone age<8: Surgery (Femoral/Salter) > Brace > No treatment
• Herring C: Bone age>8: Poor outcome irrespective of treatment

31. Classification
• Salter-Thompson Classification
• Group A: Subchondral # involving
<50 % of head
• Group B: Subchondral # involving
>50 % of head
• Applicable before fragmentation

32. Classification: Stulberg criteria for prognosis
Clas
s
Description Features Prognosis
I Spherical congruency Normal hip joint Good
II Spherical congruency;
Less than 2mm loss of
head shape
Spherical femoral head with 1 more of:
• Coxa magna
• Coxa breva
• Steep acetabulum
Good
III Aspherical congruency;
Greater than 2mm loss
of head shape
Ovoid, mushroom-shaped with 1 or more of
• Coxa magna
• Coxa breva
• Steep acetabulum
Mild-moderate arthritis
IV Aspherical congruency Flat femoral head, abnormal neck and
acetabulum
Mild-moderate arthritis
V Aspherical
incongruency
Flat femoral head with normal shaped neck &
acetabulum
Severe arthritis

33. Classification: Stulberg criteria for prognosis
I
II
III
IV V

34. Poor Prognostic features
• Age over 10 years
• Female Sex
• Degree of head involvement (Caterall & Thompson)
• 2+ Head at risk signs
• Herring C at fragmentation stage
• Premature physeal closure
• Restricted ROM
• Increased weight

35. Differential diagnosis
Practice of pediatric orthopedics
Lynn Stahelli

36. Management:

37. Management
• Principles:
1. Restore & maintain ROM
• Increases joint nutrition
• Prevents subluxation
• Allow abduction
• Satisfactory = 30⁰ ABD
2. Avoid treatment of patients who will do well without treatment
3. Concept of containment
4. Relief of symptoms

38. Management
• Objective: preserve the sphericity of the femoral head
• reduce the risk of stiffness and degenerative arthritis
• preserving the emotional well-being of the child.
• Determined by
• Age
• Extent of involvement
• Stage of disease
• Head at risk signs

39. Management: Age
• The older the child the poorer the outcome
• Role of “biological plasticity”
• Extremely poor outcome in adolescents

40. Management: Age
• Age < 5-6 years
• 50% - 70% do well without treatment
• Little evidence that treatment alters outcome
• Symptomatic treatment to regain ROM
• Regular follow-up
• Consider containment for persistent loss of ABDUCTION

41. Management:
• Concept of containment
• Harrison & Menon stated; “ if the head is
contained within the acetabular cup, then
like jelly poured into a mold the head
should be the same shape as the cup when
it is allowed to come out after
reconstitution”

42. Management:
• Methods of containment
Non-operative
• Braces & casts
Operative
• Femoral osteotomy
• Innominate osteotomy
• Shelf procedure
• Combination of femoral &
innominate osteotomy
• Tripple pelvic osteotomy

43. Management:Non-operative
• >60% do not require surgery
• Observation, activity restriction, traction
& physiotherapy
• Indications:
• <6 years age
• Herring A
• Bracing / Casting
1. Petrie cast
2. Scottish Rite brace

44. Management
• Bed rest with skin traction until the synovitis
subsides (4 to 14 days)
• Children 2 to 3 years old can be observed and do
not need aggressive treatment.

45. Management
• If significant loss of motion & lateral
subluxation:
• Closed reduction + adductor tenotomy
• Petrie cast
• Satisfactory clinical results can be obtained at
long-term follow-up despite an unsatisfactory
radiographic appearance (Cambell’s operative
orthopedics)

46. Management: Containment Surgery
• Timing of surgery: More important than the type of surgery
• Should be done before irreversible deformation of the femoral head
occurs

47. Management
• Inominate osteotomy
• Advantages:
• anterolateral coverage of the femoral head,
• lengthening of the extremity
• avoidance of a second operation for plate removal
• Disadvantages:
• Inability to obtain proper containment
• Increased acetabular & joint pressure
• Increase leg length causing relative adduction

48. Management
• Inominate osteotomy
Innominate osteotomy using quadrangular
Graft (Canale et al)
Salter innominate osteotomy

49. Management
• Lateral Shelf procedure
• Indicated in older children in later stages
• Not candidates for femoral osteotomy
• Insufficient remodeling capacity
• Shortening of limb would cause persistent limp
• Recently indicated in early active stages
1. Lateral acetabular growth stimulation
2. Prevention of subluxation
3. Shelf resolution after femoral epiphyseal
reossification

50. Management
• Lateral Shelf procedure

51. Management
• Varus derotational osteotomy
• Advaantages
• Seats the head deeply in acetabulum
• Removes vulnerable ant/lat portion from acetabular
edge
• Decrease joint reaction forces
• Disadvantages
• excessive varus angulation (especially in an older child)
• Limb shortening
• Trendelenburg gait
• Nonunion
• Hardware removal
• Premature closure of the capital femoral physis may
cause further varus deformity & trachantric overgrowth

52. Management

53. Management
Arthrodiastasis
• Distraction of joint
• Widens joint space
• Unloading of joint
• Allows fibrous repair of cartilage defects
• Preserves congruency
• Articulated fixator allows 50⁰ flexion

54. Management: Residual deformities &
complications
Hinge
abduction
Coxa breva
Trochanteric
overgrowth
Coxa
irregularis
FAI Early OA

55. Management
Reconstructive surgeries and salvage
procedures
• Valgus osteotomy
• Cheilectomy
• Shelf procedure
• Chiari osteotomy
• Trochanteric advancement

56. Management
Reconstructive surgeries and salvage
procedures
• Valgus osteotomy
• Cheilectomy
• Shelf procedure
• Chiari osteotomy
• Trochanteric advancement

57. Management
Reconstructive surgeries and salvage
procedures
• Valgus osteotomy
• Cheilectomy
• Shelf procedure
• Chiari osteotomy
• Trochanteric advancement

58. Management
Reconstructive surgeries and salvage
procedures
• Valgus osteotomy
• Cheilectomy
• Shelf procedure
• Chiari osteotomy
• Trochanteric advancement

59. Management
Reconstructive surgeries and salvage
procedures
• Valgus osteotomy
• Cheilectomy
• Shelf procedure
• Chiari osteotomy
• Trochanteric advancement

60. Management
Newer strategies
• Anti-resorptive therapy
• RANKL inhibitor – Denosumab (inhibits osteoclast formation)
• Bisphosphonates (Decrease osteoclast activity)
• Bone anabolic therapy to stimulate new bone formation
• Effects of BMP administration on bone formation in the
context of femoral head osteonecrosis are being investigated
• Intraosseous administration of bisphosphonates

61. Conclusion
• A disease surrounded by various unknown factors and several controversies
• Etiology remains unclear – multiple theories – common end point
• Although LCPD cannot be prevented, progress has been made regarding risk stratification
and minimizing its deleterious effects on the hip primarily via operative treatment
• Multiple classification systems exist – non predictive of final outcome in early stages
• No common consensus on treatment plan
• Age & degree of involvement most important
• <6yr : non-operative
• >6yr: containment surgery if Herring B / C
• 8+ yrs: poor outcome regardless of Tx, ; salavage procedures
• Current basic science research efforts and clinical studies hold out the promise of
providing patients with even better long-term results in the future.

62. THANK YOU
• Next presentation: Slipped capital femoral epiphysis
• Dr. Sirish Adhikari

63. References
• Campbell’s Operative Orthopedics 12th ed
• Practice of paediatric orthopedics 2nd ed (Lynn Stahelli)
• Apley’s system of orthopedics 9th ed
• Tachdjian’s pediatric orthopedics
• Pathophysiology and New Strategies for the Treatment of Legg-Calvé-
Perthes Disease
Harry K.W. Kim, MD, MS, FRCSC ; J Bone Joint Surg Am, 2012 Apr 04; 94 (7): 659 -669 .
• Legg-Calve-Perthes Disease: Where Are We 100 Years Later? Charles T. Mehlman,
D.O., M.P.H., FAOAO, Professor of Pediatric Orthopaedic Surgery; Jessica Blair McCourt, M.P.A.S, PA-C, Pediatric
Orthopaedic Physician’s Assistant, Cincinnati Children’s Hospital Medical Center, University of Cincinnati
College of Medicine, Cincinnati, Ohio