Overview of Legg-Calvé-Perthes disease including pathology, classification, management, prognosis

1. Legg-Calvé-Perthes
By Hiren M Divecha
CT2 T&O
28/4/2010

2. Background
 Described independently in 1910 by Legg (USA), Calvé
(France) and Perthes (Germany)
 Definition
 Self limiting
 Idiopathic
 Varying degree of ischemia
 Osteonecrosis of the capital femoral epiphysis
 Loss of blood supply to the epiphysis is thought to be
the essential lesion
 Also occurs in dogs
 Toy Poodles, Yorkshire Terriers, Pugs, Jack Russell
Terriers, and Dachshunds can be affected

3. Background
 Frequency
 US 1 in 1200 children <15 yrs
 higher in the UK esp. Ireland
 Age
 3-12 yrs (median age of 7 yrs)
 Race
 Caucasians. Rare in black races
 Sex
 M:F = 4-5: 1
 Family history:
 1 in 100 male children of adults with Legg–Calvé–Perthes
 15-20% of cases are bilateral but will be at different
stages & are asymmetric (vs. MED)

4. Aetio-pathogenesis
 Unclear
 Interrupted blood supply to capital femoral
epiphysis
 Abnormal venous drainage increases pressure
(Heikkenen 1980)
 ? Early closure of ligamentum teres artery thus
reduced metaphyseal supply (med fem circum not
fully developed) retinacular vessels only (Salter
1984)
 Retinacular vessels susceptible to pressure.
Increased risk with effusions, 4% pt with synovitis
develop Perthes. (Mukamel 1986)
 Angiographic studies reveal decreased flow in
medial circumflex femoral and superior retinacular
vessels
 ? Assoc with thrombophilia (Vosamer JBJS Am
2010)
 Factor V Leiden, protein S deficiency, prothrombin
mutation

5. Pathology
 Catterall A, Pringle J, Byers PD, et al: A review
of the morphology of Perthes disease. JBJS Br
1982;64:269-275
 11 cases necropsy specimens and in-vivo core
biopsies
 Initial stage
 Subchondral bone necrosis
 Femoral head ossification stops
 Articular cartilage continues to grow (nourished by
synovial fluid)
 XR appearance of small ossific nucleus & wide cartilage
space
 Second stage (1-3yrs)
 Resorption of necrotic bone and creeping substitution
 Third stage
 Osteoblasts, new-bone formation and healing

6. History
 Usually no history of trauma
 Limping child, often painless
 Mild – moderate hip pain
 May refer to thigh/ knee
 Incidental finding
 In childhood
 As adult

7. Examination
 Short stature – delayed bone age
 Early
 Decreased ROM – esp. internal rotation and
abduction (synovitis + muscle spasm)
 Antalgic gait
 Late
 Decreased ROM from acetabular
impingment
 Disuse atrophy of thigh muscles
 Leg length inequality due to collapse
 Trendelenburg gait

8. Differential
Unilateral Perthes Bilateral Perthes
 Septic arthritis  Hypothyroidism
 Fracture  Sickle cell
 SUFE  Multiple epiphyseal
 Transient synovitis dyspasia
(initially thought to lead  Spondyloepiphyseal
to LCPD) dysplasia tarda
 Sickle cell
 Spondyloepiphyseal
dysplasia tarda
 Gaucher's disease

9. Investigations
 Plain x-rays
 Pelvis AP + frog leg views
 Blood tests
 FBC, CRP, ESR
 Hip USS +/- aspiration if a septic joint is suspected
 Technetium 99 bone scan
 Extent of avascularity. Cold spots
 Increased uptake (recanalisation/ neovascularisation)
 Dynamic arthrography
 Assesses sphericity of femoral head
 Hinge abduction
 Bilateral Perthes
 requires skeletal survey as apart of work-up

10. Classification
 Many radiographic classification
systems exist
 Based on the extent of abnormality of
the capital femoral epiphysis
 Waldenstrom
 Catterall
 Herring
 Salter and Thompson

11. Waldenstrom (1922)
 Demonstrates which stage of the disease is present, but has no
predictive value for long-term outcome or treatment
 Initial (necrosis)
 Femoral head is radiodense and smaller, while the cartilage space of the hip is
wider
 The increased radiodensity occurs because the surrounding bone has a normal
blood supply, thus appearing osteopenic compared with the avascular segment
 Fragmentation
 Subchondral fracture, bone resorption and cyst formation
 Healing phase
 Reossification occurs peripheral to central and radiodensity becomes normal
 Remodelling
 Shape may be maintained or further flatten
 Residual deformity may be coxa magna, coxa plana, or coxa breva

12. Catterall (1971)
 Based on % involvement on AP and frog lateral (poor inter/ intra observer
error)
 Group 1
 Anteromedial proportion only, physis and metaphysis OK
 heal without sequelae
 Group 2
 nearly 50% involvement
 fragmentation without significant collapse
 minimal metaphyseal involvement
 good result
 Group 3
 nearly 75%
 triangle of normal bone postermedially, lateral collapse
 diffuse metaphyseal involvement
 poorer result
 Group 4
 100% involvement
 widespread collapse diffuse metaphyseal +/- physis
 sequestra formation
 poor result

14. Herring (1992/2004)
 Based on degree of collapse of lateral pillar
involvement during fragmentation stage
 Group A
 no collapse. No progressive flattening
 Group B
 < 50% collapse
 Group B/C border
 ≤ 50% collapse. Narrow (2-3mm). Little ossification
 Group C
 > 50% collapse. 17% develop progressive flattening
 Ritterbusch 1993
 Greatest predictive value & interobserver reliability

16. Poor Prognosis
 Age
 <6 yrs – good regardless of treatment
 6-8 yrs – not always satisfactory with containment
 >10yrs – questionable benefit from containment. poor prognosis. significant
symptoms and restricted ROM
 Lateral pillar stage
 >50% lateral pillar collapse Herring JA et al J Pediatr Orthop 13:281-285,
1993
 Ismail and MF Macincol JBJS Br 1998 – none group C had normal hip,
irrespective of age
 Sex = F
 Radiological morphology at completion (Stuhlberg 1981)
 flat topped femoral head which is incongruent w/ the acetabulum has the
worst prognosis
 Decreased ROM, adduction contracture, flexion with abduction,
heavy child
 Catterall head at risk signs
 lateral subluxation
 100% involvement
 calcification lateral to physis
 metaphyseal cysts
 Gage sign (lateral V shaped defect)
 horizontal physis

17. Treatment
 Goals of treatment
 Maintain femoral head
sphericity/ containment
 Avoid severe degenerative
arthritis
 Guided by
 Age of onset
 Severity of involvement
 Limitation in ROM

18. Conservative
 NSAIDs + rest till
acute pain subsides
 ? traction
 Physiotherapy ROM
 Containment
 Lat sublux, lat pillar
collapse
 Petrie cast or brace
 Exclude hinge
abduction
 Wean off when
reossification starts
 Spherical
remodelling

19. Intervention
 Herring 2004
 A – good outcome regardless
 B <8yrs – good outcome
 B/C 6-8yrs – no benefit from surgery
 B & B/C >8yrs benefit from surgery
 Containment by surgery (before reossification)
 Femoral varus osteotomy +/- derotation
 Salter osteotomy
 Combination
 Femoral neck lengthening
 Triple pelvic osteotomy

20. <6yrs 6-8yrs >8yrs
A, B B/C, C Contained
A, B B/C , C Uncontained
Contained Uncontained Coxa vara/
Good mobility Poor Mobility Coxa magna
Good mobility Poor mobility magna
Triple pelvic
Varus / Salter Varus / Salter VITO, femoral osteotomy,
Conservative Conservative
osteotomy osteotomy neck lengthening femoral neck
legthening

21. Varus osteotomy Salter Osteotomy

22. Femoral neck
lengthening Triple pelvic osteotomy

23. 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
 Gower & Johnston – mid 30s. 86% good outcome. 8% arthroplasty
 McAndrew & Weinstein – mid 50s. 40% good outcome. 40%
arthroplasty
 Long Term Consequences
 coxa magna
 coxa breva
 hinged abduction
 Enlarged, laterally extruded femoral head impinges against
acetabular rim
 degenerative changes

24. When it goes wrong
 Valgus osteotomy
 Hip arthroplasty!

25. References
 Skaggs DL. Legg-Calve-Perthes Disease. JAAOS 1996;4:9-16
 Catterall A. The natural history of Perthes disease. JBJS Br
1971;53:37-53
 Catterall A. A review of the morphology of Perthes disease.
JBJS Br 1982;64:269-275
 Herring JA. The lateral pillar classification of Legg-Calve-
Perthes disease. JPO 1992; 12:143-150
 Ritterbusch JF, Shantharam SS, Gelinas C. Comparison of
lateral pillar classification and Catterall classification of Legg-
CalveŽ -Perthes disease. JPO 1993;13:200-202
 Herring. Legg-Calvé-Perthes Disease. Part I: Classification of
Radiographs with Use of the Modified Lateral Pillar and
Stulberg Classifications. JBJS Am 2004; 86:2103-2120
 Herring. Legg-Calvé-Perthes Disease Part II: Prospective
Multicenter Study of the Effect of Treatment on Outcome.
JBJS Am 2004; 86:2121-4