1. Legg-Calvé-Perthes Disease by John A. Herring, Hui Taek Kim, and Richard Browne J Bone Joint Surg Am Volume 86(10):2103-2120 October 1, 2004 ©2004 by The Journal of Bone and Joint Surgery, Inc.

2. An example of a hip in group A of the lateral pillar classification in a patient who was 9.7 years old at presentation. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

3. An example of a hip in the B/C border group of the lateral pillar classification in a patient who was 7.1 years old at presentation. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

4. An example of a hip in group C of the lateral pillar classification in a patient who was 8.3 years old at presentation. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

5. An example of a hip in group B of the lateral pillar classification in a patient who was 7.4 years old at presentation. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

6. An example of a hip in the B/C border group of the lateral pillar classification in a patient who was 8.5 years old at presentation. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

7. An example of a hip in the B/C border group of the lateral pillar classification in a patient who was 8.1 years old at presentation. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

8. An example of a class-I hip according to the Stulberg classification in a patient who was 9.8 years old at presentation, when the hip was categorized as group B according to the lateral pillar classification. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

9. Frog-leg lateral radiograph, made at the age of seventeen years, showing no differences between the two hips. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

10. An example of a class-II hip according to the Stulberg classification in a patient who was 8.8 years old at presentation, when the hip was categorized as group B according to the lateral pillar classification. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

11. Frog-leg lateral radiograph, made at the age of 17.0 years, showing a round femoral head on the right, which is slightly larger than the left femoral head. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

12. A method for distinguishing between Stulberg class-II and III hips. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

13. A perpendicular is erected at the center of the line. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

14. A best-fit circle is drawn to match the surface of the femoral head. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

15. With use of the same radius, a best-fit circle is drawn over the surface of the femoral head on the frog-leg lateral radiograph. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

16. In this example, the circle fails to fall within 2 mm of the surface of the femoral head on the frog- leg lateral radiograph. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

17. An example of a class-III hip according to the Stulberg classification. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

18. Frog-leg lateral radiograph, made at the age of sixteen years and seven months, showing an ovoid femoral head. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

19. An example of a class-IV hip according to the Stulberg classification. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

20. Frog-leg lateral radiograph, made at the age of fifteen years and three months, showing more severe flattening of the femoral head. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

21. Another class-IV hip according to the Stulberg classification. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

22. Frog-leg lateral radiograph, made at the age of seventeen years and four months, showing severe flattening of both femoral heads. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

23. A class-V hip according to the Stulberg classification. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.

24. Frog-leg lateral radiograph, made at the age of thirteen years and three months, showing marked subluxation and incongruity between the femoral head and the acetabulum. John A. Herring et al. J Bone Joint Surg Am 2004;86:2103- 2120 ©2004 by The Journal of Bone and Joint Surgery, Inc.