1. Reliability and Stability of Three Common Classifications for Legg-Calve-Perthes Disease
Good morning, ladies and gentlemen. Please let me introduce myself. I am Chin youb Chung from the department of pediatric orthopedic surgery at Seoul national university Bundang hospital. It is a pleasure for me to give a presentation at this session. Thank you all for coming today to this presentation.
My topic is ‘validity and reliability of physical examinations and radiographic measurement evaluating patients with cerebral palsy for single event multilevel surgery.’
Ki Hyuk Sung, MD
Department of Orthopaedic Surgery
Seoul National University Bundang Hospital

2. Introduction Legg-Calve-Perthes disease (LCPD)
An osteochondrosis that affects the proximal epiphysis of the femur
Treatment : observation, nonsurgical containment using orthotic device, surgical containment procedure, salvage procedure

3. Introduction Three common classification for LCPD
Catterall classification
Salter and Thompson classification
Herring classification

4. Catterall I

5. Catterall II

6. Catterall III

7. Catterall IV

8. Type A
Type B

9. Herring A

10. Herring B

11. Herring C

12. Introduction
Stability refers to the extent to which patients remain in the same classification level over time
Poor stability indicates progression of the disease and more aggressive treatment is needed

13. Introduction
If the range of stability of classification systems can be established, it would be possible to predict the course of the disease in the early stages

14. Purpose
To evaluate the reliability and stability of the classification system for LCPD.

15. Material and methods

16. Inclusion and exclusion criteria
Patients with two or more sets of radiographs taken a minimum of 3 month intervals   
Exclusion
Patients who visited only once before surgery (femoral osteotomy or pelvic osteotomy)
Patients who classified as the reossification and remodeling stage at the initial visit

17. A consensus building session before radiographic measurement
36 radiographs and 3 raters for interrater and intrarater reliability
Changes in classifications among initial rating, rating at early fragmentation, and final rating for stability

18. Statistical Methods Interrater and intrarater reliability Stability
ICC and 95% CI
Stability
percentage agreement and ICC with 95% CI

19. Results

20. Demographics 69 patients (60 males/ 9 females)
Mean age: 6.5 years ( )
Mean time between initial and final rating
: 1.2 ± 0.7 (SD) years
A total 379 ratings (mean 5.5 ±2.1 per child)

21. Interrater reliability
Classification system
ICC
95% CI
Herring (Session 1)
0.894
Herring (Session 2)
0.888
Catterall (Session 1)
0.805
Catterall (Session 2)
0.796
Salter-Thompson (Session 1)
0.633
Salter-Thompson (Session 2)
0.735

22. Intrarater reliability
Classification system
ICC
95% CI
Herring (Examiner 1)
0.907
Herring (Examiner 2)
0.951
Herring (Examiner 3)
0.908
Catterall (Examiner 1)
0.915
Catterall (Examiner 2)
0.813
Catterall (Examiner 3)
0.810
Salter-Thompson (Examiner 1)
0.823
Salter-Thompson (Examiner 2)
0.751
Salter-Thompson (Examiner 3)
0.659

23. Herring classification for initial and final rating of patients with Legg-Calve-Perthes disease
Initial rating
Final rating A B
B/C C
Total 5 19 3 30 - 24 1 8 43 7 14 69
Percent agreement, 55%; intraclass correlation coefficient, (95% CI, ).

24. Herring classification for rating at early fragmentation and final rating of patients with Legg-Calve-Perthes disease
Rating at early fragmentation
Final rating A B
B/C C
Total 2 6 1 - 9 33 4 39 7 13 61
Percent agreement, 79%; intraclass correlation coefficient, (95% CI, ).

25. Catterall classification for initial and final rating of patients with Legg-Calve-Perthes disease
Initial rating
Final rating I II
III IV
Total 1 2 4 9 - 10 19 6 7 13 24 20 42 65
Percent agreement, 48%; intraclass correlation coefficient, (95% CI, to 0.634).

26. Catterall classification for rating at early fragmentation and final rating of patients with Legg-Calve-Perthes disease
Rating at early fragmentation
Final rating I II
III IV
Total - 1 2 3 16 10 26 28 40 57
Percent agreement, 79%; intraclass correlation coefficient, (95% CI, ).

27. Conclusion
The classification of Herring et al has the highest interrater and intrarater reliability among three classification systems 
However, over 40% of the hip radiographs at the initial presentation, in particular, most of Herring group A patients were upgraded

28. Conclusion
Therefore, we should keep in mind the possibility of surgical treatment for the patients who were over 8 years of age and initially graded as Herring group A

29. Thank you for your attention!