1) Pathologic fractures are fractures that occur in abnormal bone. The term can be used in the case of generalized metabolic bone disease, it is usually reserved for fractures through a focal abnormality which may be malignant or non-malignant.
- Examples of generalized metabolic bone disease: Rickets, osteoporosis, chronic renal insufficiency, chronic liver disease, osteogenesis imperfecta (OI), McCune-Albright syndrome, and osteopetrosis
- Examples of focal abnormalities: primary bone tumors, metastases, osteomyelitis, bone cysts
2) The proximal femur and humerus are the most frequent sites for pathologic fractures.
3) Unicameral (simple) bone cysts, aneurysmal bone cysts, and nonossifying fibromas are the most common tumors leading to pathologic fractures. Osetogenesis imperfecta (OI) is the most common metabolic bone disorder that causes pathologic fractures. Other clues to OI are: short stature, scoliosis, basilar skull deformities, hearing loss, blue sclerae, opalescent teeth, ligamentous laxity, and easy bruisability.
4) In circumstances where other pathologies are excluded (such as cancer), a pathologic fracture is diagnostic of osteoporosis irrespective of bone mineral density.