Fig. 1

Preoperative and postoperative images at the time of the first surgery. (a, b) Preoperative lateral and anteroposterior X-rays show sclerotic lesions in the neck of the talus. (c, d) Preoperative sagittal T2-weighted and coronal T2-weighted magnetic resonance images of the left ankle show bone marrow oedema of the talus, left ankle joint effusion, and soft tissue swelling around the joint. An approximately 1-cm-diameter nodular shadow with an unclear boundary is seen in the upper front aspect of the left talus, and a small amount of effusion is present in the joint cavity (red arrow indicates the nidus). (e, f) Sagittal T2-weighted and coronal T2-weighted magnetic resonance images obtained 3 months after the first surgery show widespread bone marrow oedema of the talus