Legg Calve Perthes Disease (LCPD) is osteonecrosis of the femoral head that typically affects children between the ages of 4-10. For patients under 6 years old with minimal involvement, the prognosis is generally good and treatment involves rest and anti-inflammatories. For patients between 6-8 years old with more involvement, containment of the femoral head through bracing or surgery is often recommended. Patients presenting after age 9 usually have a poor prognosis due to more advanced involvement and are treated with early containment procedures, though stiffness can be a complication.

1. Legg Calve Perthes Disease

2. History FIRST DESCRIBED BY LEGG AND WALDENSTORM IN 1909 AND BY PERTHES AND CALVE IN 1910

3. Definition Legg-Calvé-Perthes disease (LCPD) is the name given to idiopathic osteonecrosis of the capital femoral epiphysis in a child.

4. Epidemiology Disorder of the hip in young children Usually ages 4-8yo As early as 2yo, as late as teens Boys:Girls= 4-5:1 Bilateral 10-12% No evidence of inheritance

5. Prevalence :

6. Etiology Unknown Past theories: infection, inflammation, trauma, congenital Most current theories involve vascular compromise Sanches 1973: “second infarction theory”

7. Causes Proposed theories . Excessive femoral antiversion. Synovitis. Generalized skeletal disorder. Arterial anomalies.

9. Pathogenesis Histologic changes described by 1913 Secondary ossification center= covered by cartilage of 3 zones: Superficial Epiphyseal Thin cartilage zone Capillaries penetrate thin zone from below

10. Epiphyseal cartilage in LCP disease: Superficial zone is normal but thickened Middle zone has 1) areas of extreme hypercellularity in clusters and 2) areas of loose fibrocartilaginous matrix Superficial and middle layers nourished by synovial fluid Deep layer relies on blood supply

11. Physeal plate : cleft formation, amorphis debris, blood extravasation Metaphyseal region : normal bone separated by cartilaginous matrix Epiphyseal changes can be seen also in greater trochanter, acetabulum

12. Blood Supply

13. Radiographic Stages Four Waldenstrom stages: 1) Initial stage 2) Fragmentation stage 3) Reossification stage 4) Healed stage

14. Initial Stage Early radiographic signs: Failure of femoral ossific nucleus to grow Widening of medial joint space “ Crescent sign” Irregular physeal plate Blurry/ radiolucent metaphysis

15. Fragmentation Stage Bony epiphysis begins to fragment Areas of increased lucency and density Evidence of repair aspects of disease

16. Reossification Stage Normal bone density returns Alterations in shape of femoral head and neck evident

17. Healed Stage Left with residual deformity from disease and repair process Differs from AVN following Fx or dislocation

18. Group I

19. Group II

20. Group III

21. Group IV

22. 3 groups: A) no lateral pillar involvment B) >50% lat height intact C) <50% lat height intact Lateral Pillar Classification

23. Salter-Thompson Classification Simplification of Catterall Based on status of lateral margin of capital femoral epiphysis Group A (Catterall I & II equivalent) Group B (Catterall III & IV equivalent)

24. Clinical Features Stature usually shorter than peers Quadriceps and gluteal muscle wasting is common, Trandelenburg test positive (drop of the hip on the unsupported side) Acute phase; range of motion at the hip joint is limited due to muscle spasms Progressively; limited internal rotation and abduction is likely due to impingement lesions (hence the Roll test, guarding on affected side) Later stage; global reduction in all ranges of motion assoc. with pain, indicating joint arthritis

25. Age- 4 to 10 years, with peak incidence at 7 Gender- Boys (5:1 ratio) but it tends to be more severe in girls Height Passive smoking or maternal smoking at pregnancy ADHD? Increased physical activity Family Hx of; skeletal dysplasias or thrombotic disease Ethnicity; more common in Whites, Eskimos, Japanese Social Hx- associated with low socio-economic status Risk Factors

26. Differential Diagnosis

27. Workup Technetium 99 bone scan - Helpful in delineating the extent of avascular changes before they are evident on plain radiographs. The sensitivity of radionuclide scanning in the diagnosis of LPD is 98%, and the specificity is 95%. Dynamic arthrography - Assesses sphericity of the head of the femur.

28. Ultrasonography may provide significant diagnostic clues to differentiate early Perthes' from transient synovitis. T Futami, Y Kasahara, S Suzuki, S Ushikubo and T Tsuchiya Journal of Bone and Joint Surgery - British Volume, Vol 73-B, Issue 4, 635-639 Ultrasonography in transient synvitis and early Perthes’ disease

29. CT Scan Staging determined by using plain radiographic findings is upgraded in 30% of patients. Not as sensitive as nuclear medicine or MRI. CT may be used for follow-up imaging in patients with LPD.

30. MRI It allows more precise localization of involvement than conventional radiography. MRI is preferred for evaluating the position, form, and size of the femoral head and surrounding soft tissues. MRI is as sensitive as isotopic bone scanning.

31. Outcome variables Age Extent of involvement Duration Remodeling potential Premature physeal closure Type of treatment Stage of disease at treatment.

32. Treatment Options Overall goal of treatment Reduce hip irritability and pain Restore/maintain hip mobility Prevent femoral head from extruding or collapsing “CONTAINMENT ” Regain spherical shape of femoral head

33. Below 6 years and Herring A/B Mainstay of treatment would be to OBSERVE with 6-12 month reassessment. Patients in this age group need bed rest and anti inflammatory medication at most. NO evidence that abduction splints or surgery beneficial Prognosis is good for the majority

34. Non Surgical treatment NSAIDS Traction Casts and braces (Scottish Rite Orthosis)

35. Above 6 and Herring class B Containment of the head within the acetabulum is warranted This is achieved by; Abduction bracing Femoral varus osteotomy Pelvic ostotomy

36. Age between 6-8 and Herring class C Results of intervention have been equivocal. Above 9 years Often have Herring class B or C Prognosis is poor Early containment is key, by pelvic osteotomy and internal fixation

37. Osteotomies

38. Summary For patients less that 6 years old the prognosis is good for the majority. If they are stiff or painful they respond to bed rest, traction and pain relieving anti-inflammatory medication. There is no evidence that abduction splints or surgical intervention is warranted in the majority of these younger patients.

39. For patients between 6 and 8 years but with a bone age less than 6 and an intact lateral pillar (Herring A and B) the prognosis is similar to that for the first group and observation is as good as surgical intervention for the majority. If they have bone ages greater than 6 years and Herring lateral pillar classification B then &quot;containment&quot; of the head within the acetabulum seems to be warranted. This may be done by abduction bracing, femoral varus osteotomy or a pelvic osteotomy.

40. If they are between 6 and 8 and are in lateral pillar group C then the result of intervention are equivocal. Children presenting with Perthes disease at age 9 or older often have lateral pillar B or C and a poor prognosis. The trend is towards early containment of these hips although stiffness can be a problem following early pelvic (Salter's) osteotomy.

41. 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.

42. Complications Femoral Shortening stiffness Malrotation Limp Positive trendelenburg Pelvic Lenghtening Stiffness Chondrolysis Failure of containment

43. Prognosis The younger the age of onset of LCPD, the better the prognosis. Children older than 10 years have a very high risk of developing osteoarthritis. Most patients have a favorable outcome. Prognosis is proportional to the degree of radiologic involvement.