Arthroscopic Excision of Osteoid Osteoma of the Talus Iftach Hetsroni, M.D., Meir Nyska, M.D., Evgeny Edelshtein, M.D., Ph.D., Gideon Mann, M.D., Ezequiel Palmanovich, M.D.  Arthroscopy Techniques  Volume 6, Issue 3, Pages e839-e843 (June 2017) DOI: 10.1016/j.eats.2017.02.016 Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 1 Lateral dorsiflexion radiograph of the right ankle showing anterior ankle impingement between the dorsal talar osteophyte (asterisk) and anterior tibia. Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 2 Sagittal CT view of the right ankle showing relationships between dorsal talar osteophyte (asterisk) and area of nidus with reactive sclerosis (arrows) (upper image), and 3-dimensional CT reconstruction showing extent of dorsal talar osteophyte (asterisk) as expected to be later observed during arthroscopy (lower image). (CT, computed tomographic.) Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 3 Sagittal magnetic resonance imaging views of right ankle showing bone edema at talar neck area around nidus. The bone edema is seen on T2-weighted STIR sequence as an increased signal (encircled) (upper image) and on T1-weighted sequence as a decreased signal (encircled) (lower image). This is supportive of the diagnosis of osteoid osteoma. (STIR, short tau inversion recovery.) Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 4 Arthroscopic view of a right ankle using a 30° arthroscope (Olympus, Center Valley, OA) through the anterolateral portal at the initiation of the arthroscopy. The anterior talar dome is clearly seen, while the dorsal talar osteophyte is covered with soft tissue. Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 5 Arthroscopic view of a right ankle using a 30° arthroscope (Olympus, Center Valley, OA) through the anterolateral portal revealing the dorsal talar osteophyte after the soft tissue coverage of the osteophyte was resected. Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 6 Arthroscopic view of a right ankle using a 30° arthroscope (Olympus, Center Valley, OA) through the anterolateral portal. Using the 4.0-mm resector cutter (Stryker, San Jose, CA), a thin layer of bone is resected just at the area of the talar neck that covers the nidus location, in accordance with the preoperative CT images. (CT, computed tomographic.) Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 7 Arthroscopic view of a right ankle using a 30° arthroscope (Olympus, Center Valley, OA) through the anterolateral portal. A 5.0-mm curette (Zimmer, Dover, OH) is used to excise bone from the area that corresponds to the nidus location. Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 8 Arthroscopic view of a right ankle using a 30° arthroscope (Olympus, Center Valley, OA) through the anterolateral portal. Cherry-red area that corresponds to nidus macroscopic appearance is identified. Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 9 Arthroscopic view of a right ankle using a 30° arthroscope (Olympus, Center Valley, OA) through the anterolateral portal. Nidus excision was completed with the use of a 4.0-mm round burr (Stryker, San Jose, CA). Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 10 Histopathologic examination of the excised lesion. On the left image, a small fragment of sharply demarcated interlacing network of osteoid and bony trabeculae with variable mineralization is seen, arranged in a random tangle of anastomoses. The nidus, composed of osteoid and bony trabeculae, is encircled in red. Sharply demarcated cortical sclerotic bone is marked with red arrow (H&E, ×100). On the right image, the intertrabecular spaces contain a proliferation of capillaries and some fibroblasts, with few benign giant cells. A rim of layer of osteoblasts is marked with open arrows, while a single benign multinucleated cell is marked with a black arrow (H&E, ×400). The features are consistent with nidus of osteoid osteoma. In addition, few fragments of sclerotic bone are seen. (H&E, hematoxylin-eosin.) Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 11 Lateral radiograph of the right ankle after resection of the dorsal talar osteophyte. Arthroscopy Techniques 2017 6, e839-e843DOI: (10.1016/j.eats.2017.02.016) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions