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| IMAGE QUIZ ARCHIVE | ||||||
| Image Quiz | ||
| Painful Ankle (continued) | ||
| Answer: Aneurysmal bone cyst. | ||
 Fig. 4 |
Fig. 4 Intraoperative view of the débrided cystic area within the talus. An anterior approach was used. For larger view, click on image |
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 Fig. 5 |
Fig. 5 The resulting defect was packed with polymethylmethacrylate cement. For larger view, click on image |
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| The cyst was managed operatively. An anterior approach to the talus was used, and the lesion was débrided (Fig. 4) and then packed with polymethylmethacrylate bone cement (Fig. 5). Histologic analysis confirmed the diagnosis of an aneurysmal bone cyst. | ||
| At the six-month follow-up appointment, the patient described a reduction in pain and there was a marked improvement in the range of movement. Radiographs of the ankle revealed some calcification in the anterior joint capsule but no recurrence of the lesion (Fig. 6). | ||
 Fig. 6 |
Fig. 6 Six months after the operation, radiographs show slight calcification in the anterior joint capsule but no recurrence of the lesion. For larger view, click on image |
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| Discussion | ||
| Aneurysmal bone cysts are thin-walled, expansile osteolytic lesions in which a blood-filled cystic cavity is separated by fibrous tissue containing multinucleated giant cells. The term "aneurysmal" refers to the appearance of the cyst on radiographs. These lesions may occur in patients of any age and in any bone, although they are more commonly seen in the metaphyses of long bones in young adults, and they are found in females twice as often as they are found in males. Aneurysmal bone cysts of the talus are extremely rare1. | ||
| Aneurysmal bone cysts develop as a component of, or arising within, a preexisting bone lesion in about one-third of patients. The most common precursor lesion is a giant cell tumor (found in 19% to 39% of patients), followed by osteoblastoma, angioma, and chondroblastoma. Less common precursor lesions are fibrous dysplasia, nonossifying fibroma, chondromyxoid fibroma, fibrous histiocytoma, eosinophilic granuloma, and osteosarcoma2. The pathogenesis of aneurysmal bone cysts has also been linked to posttraumatic local hemodynamic alterations related to venous obstruction or arteriovenous fistulae3. The link between trauma and the presentation of an aneurysmal bone cyst in our patient remains speculative. | ||
| The trauma sustained by the patient resulted from "falaka" or "falanga," a commonly used instrument of torture favored in certain countries. The victim's feet are fastened to a pole, and the soles are then repeatedly struck with sticks (Fig. 7). This produces intense pain but leaves minimal residual physical signs. Bone scintigraphy has been shown to be useful in substantiating allegations of such abuse4,5. | ||
 Fig. 7 |
Fig. 7 Photograph showing the manner in which "Falaka" is performed. For larger view, click on image |
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| The most widely accepted method of treating aneurysmal bone cysts is surgical curettage and bone grafting. Adjuvant therapy, including phenol, cryotherapy, or methylmethacrylate, is sometimes used to extend the surgical margin by causing osteonecrosis and microvascular damage to the walls of the excised cyst6,7. This is done in the hope of reducing recurrence, but, despite these interventions, recurrence remains a problem, with reported rates of 10% to 70%8. | ||
| Bone cement was chosen to fill the resulting talar defect in our patient because of the lack of a firm diagnosis and the hope that the proposed exothermic "tumor kill" treatment would be beneficial if the results of histologic analysis suggested anything more sinister than an aneurysmal bone cyst. We acknowledge that this treatment may lead to a potential stress riser within the talar neck and may also complicate a subsequent fusion, should that option become necessary. | ||
| The very rare case of aneurysmal bone cyst of the talus in our patient reinforces the need for an increasing awareness of the medical issues that may affect political asylum seekers and refugees9,10. The proportion of asylum seekers who have been tortured varies from 5% to 30%9 and approximately 8% of all applications for political asylum are made on the basis of torture11. Advice and support is available from the Medical Foundation for the Care of Victims of Torture12. | ||
| *The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated. | ||
| References | ||
| 1. Soreff J. Aneurysmal bone cyst of the talus. Acta Orthop Scand. 1976;47:358-60. |
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