An Uncommon Presentation of an Uncommon Bone Tumor: A Case Study of a Pathologic Fracture of an Intertrochanteric Aneurysmal Bone Cyst

Aneurysmal bone cyst: a review

Aneurysmal bone cyst (ABC) is a benign locally destructive bone neoplasm composed of multi-loculated blood-filled cystic spaces. The most common sites of involvement are the meta-diaphysis of the long bones and posterior elements of the vertebrae. Secondary, ABC-like changes can complicate a variety of other benign and malignant primary bone neoplasms, including giant cell tumor, fibrous dysplasia, and osteosarcoma. About two-third of primary ABCs have a rearrangement of the USP6 gene, which is not present in the ABC-like changes that occur secondary to other primary bone tumors (i.e., secondary ABC). Primary ABC of bone carries a variable but generally high rate of local recurrence. This paper provides an overview of the pathophysiology, clinical presentation, radiographic and pathologic findings, treatment, and prognosis of ABC.

Strategies for managing the destruction of calcar femorale

BACKGROUND

The calcar femorale was identified long ago. However, our current understanding of the calcar is insufficient, and its related concepts are sometimes confused. The calcar femoral is an important anatomical structure of the proximal femur, and its function can be overlooked. In trauma, tumors, or other diseases, the calcar femorale can be destroyed or changed pathologically. As a result, the mechanical structure of the proximal femur becomes destroyed, causing pathological fractures. How to address the destruction of the calcar femorale or the damage to the calcar femorale is discussed in this article.

MAIN TEXT

Destruction of the calcar femorale is accompanied by many conditions, including trauma, tumors, and other diseases. The types of hip fractures caused by trauma include femoral neck fractures and intertrochanteric fractures. Dynamic hip screws, proximal femoral nail anti-rotation, and multiple parallel cannulate pins can be used in different conditions. When metastatic and primary bone tumors involve the calcar femorale, endoprostheses are widely used. Other diseases, such as fibrous dysplasia and aneurysmal bone cyst are treated differently.

CONCLUSIONS

The calcar femorale can redistribute stresses and the destruction of the calcar femorale can lead to an increase in posterior medial stress. Many factors need to be considered when deciding whether to reconstruct the calcar femorale. Effective treatment strategies for managing the destruction of calcar femorale will need first establishing the precise mechanism of the destruction of the calcar and then designing therapies towards these mechanisms. Further investigation to the calcar needs to be carried out.