1. Spontaneous Osteonecrosis of the Knee: The Result of Subchondral Insufficiency Fracture* by Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am Volume 82(6):858-858 June 1, 2000 ©2000 by The Journal of Bone and Joint Surgery, Inc.

2. Diagrams depicting the histopathological classification of the lesion. Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.

3. Figs. 2-A through 2-D: Case 3, a seventy-two-year-old man who had a sudden onset of knee pain without any history of antecedent trauma.Fig. 2-A: Anteroposterior standing radiograph of the right knee, made seven months after the onset of pain, showing subcho... Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.

4. . Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.

5. Magnetic resonance images made seven months after the onset of pain. Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.

6. Photomicrograph of a specimen obtained from the area beneath the articular cartilage, demonstrating fractured bone trabeculae with associated fracture callus and vascular granulation tissue, without any evidence of antecedent osteonecrosis (hematoxylin and... Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.

7. Figs. 3-A through 3-D: Case 8, a seventy-two-year-old woman who had a sudden onset of pain without any history of antecedent trauma.Fig. 3-A: Anteroposterior standing radiograph of the left knee, made eleven months after the onset of pain, demonstrating sub... Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.

8. Magnetic resonance images made eleven months after the onset of pain. Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.

9. . Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.

10. Photomicrograph demonstrating a fracture line in the subchondral area, paralleling the subchondral osseous end plate. Takuaki Yamamoto, and Peter G. Bullough J Bone Joint Surg Am 2000;82:858 ©2000 by The Journal of Bone and Joint Surgery, Inc.