1. Legg-Calve-Perthes Disease (coxa plana, osteochondrosis capitis femoris avascular necrosis of the femoral head)

2. Definition
Idiopathic osteonecrosis of the capital femoral epiphysis of the femoral head of unknown aetiology.
It is a self-limited disease.

3. Etiology Infection, trauma, synovitis
Disruption of blood flow to capital femoral epiphysis (CFE)‏
Systemic disorder (delayed skeletal maturation, abnormalities of thyroid hormone and insulin like growth factor
Hereditary influence, environmental influence, hyperactivity

4. Blood flow to CFE

5. Epidemiology
One in 1200 children younger than 15 years is affected by LCPD
Males are affected 4-5 times more often than females
LCPD most commonly is seen in persons aged 4-8 (2-12) years, with a average age of 7 years
Bilateral involvment %
DDH – 25%

6. Pathology
The blood supply to the capital femoral epiphysis is interrupted (arteries and veins).
Bone infarction occurs, especially in the subchondral cortical bone, while articular cartilage continues to grow. (Articular cartilage grows because its nutrients come from the synovial fluid.)‏
Revascularization occurs, and new bone ossification starts.
Changes to the epiphyseal growth plate occur secondary to the subchondral fracture.

7. Symptoms Painless limp
Hip or groin pain, which may be referred to the thigh
Mild or intermittent pain in anterior thigh or knee
Usually no history of trauma

8. Symptoms
Decreased range of motion (ROM), particularly with internal rotation and abduction
Painful gait
Atrophy of thigh muscles secondary to disuse
Muscle spasm- mild hip contracture of degrees may be present

9. Symptoms Leg length inequality due to collapse
Thigh atrophy: Thigh circumference on the involved side will be smaller than on the unaffected side secondary to disuse (Trendelenburg sign)‏

10. Trendelenburg sign

11. Diagnosis Clinical presentation, physical examination
RTG- A-P, frog-leg lateral views (every 6 weeks at the beginning, every 3-6 months later)‏
USG- synovitis
MRI, artrography

12. Stages – radiographic presentation
Ischaemia / Necrosis
Fragmentation / Resorption
Reossification / Healing
Residual stage

13. Initial stage- necrosis
Decreased size of ossification center
Lateralization of femoral head
Subchondral fracture
Physeal irregularity

14. Fragmetation- resorption
Fragmented epiphysis
More irregular acetabular contour

15. Reossification- healing
New bone formation- the bone density returns

16. Residual stage Reossified femoral head Remodeling of the head shape
Remodeling of the acetabulum

17. Catterall classification
Stage 1:
Antero-medial portion of head involved and no collapse, metaphyseal changes do not occur and the epiphyseal plate is not involved
Heal without significant sequelae
Stage 2:
More head involved and may - fragmentation of the involved segment
The involved segment shows increased density and uninvolved pillars of normal bone prevent significant collapse - regeneration without much loss of height and the end result is usually good. Metaphyseal reaction localised

18. Catterall classification
Stage 3:
More of the head involved - collapse as uninvolved pillars not large enough t prevent collapse
May show head within a head
The metaphysis is usually diffusely involved - broad neck and the epiphyseal plate is unprotected and also usually involved - results poorer
Stage 4:
Whole head involvement and severe collapse occurs early and restoration of the femoral head usually less complete
The metaphyseal changes may be extensive
The epiphyseal plate is often involved - abnormal growth (coxa magna, coxa breva, coxa vara and coxa valga)

19. Herring classification
Lateral pillar clasification
Detrmine treatment and prognosis

20. Salter - Thompson Classification
Stage A: - Lateral portion of femoral capital epiphysis present - less than 50% head involved
Stage B: - Lateral portion of femoral capital epiphysis absent - more than 50% head involved (Lateral margin of epiphysis protects epiphysis from stress)‏

21. Differential diagnosis

22. Mose method
If head conforms to a single ring in both X- Ray planes - good prognosis
If head varies from perfect circle by no more than 2mm - fair results
If head varies by more than 2mm in any plane - poor results

23. Neck-shaft angle

24. Centre-edge angle (Wiberg`s angle)

25. Centre-edge angle 5-8 years ~19 degrees 9-12 years ~25 degrees

30. Goal of treatment
Preservation of the roundness of the femoral head and prevention of deformity while the condition runs its course.

31. Conservative treatment
Relieve weight bearing
Achieve and maintain ROM
Containment of the femoral epiphysis within the confines of the acetabulum (Petrie-style casts, Atlanta /Scottish Rite/ brace, Toronto brace and other orthotic devices)‏

32. Conservative treatment

33. Conservative treatment

34. Conservative treatment

35. Surgical treatment
Femoral osteotomy = varus +/- derotation to reduce the degree of anteversion & extension.
Pelvic osteotomy (Salter, Chiari, Shelf) or Femoral osteotomy have similar results

36. Surgical treatment
Shelf acebuloplasty

37. Surgical treatment
Salter osteotomy

38. Very good radiographic results befrore surgery (7 years 2 months)‏

39. Very good radiographic results 3 years after surgery

40. Very good radiographic results 6 years after surgery

41. Poor radiographic result before surgery (7 years 8 months)‏

42. Poor radiographic result 6 months after surgery

43. Poor radiographic result 8 years after surgery