pseudofractures

Pseudofractures, also known as Looser zones, are incomplete fractures in bone that appear as transverse or oblique radiolucent lines with sclerotic margins along the cortex. They do not traverse the full width of the bone and are considered signs of stress or defective mineralization rather than true complete fractures.

Most commonly they occur in osteomalacia and vitamin D deficiency, though they may be seen in other conditions causing impaired bone mineralization, such as chronic kidney disease or malabsorption. They arise when weakened bone under mechanical load develops microcracks that fail to mineralize properly, leading to a partially broken but not fully separated cortex.

Radiographically, pseudofractures appear as bilateral or multiple bands of lucency with sclerotic borders, often near weight-bearing cortices such as the femoral neck, pubic rami, ischial bones, tibia, ribs, or clavicle. They can be seen on plain X-rays and may be demonstrated with bone scans or MRI.

Clinically, pseudofractures indicate an underlying disorder of bone mineralization and are associated with bone pain, muscle weakness, and a tendency toward fractures. Laboratory evaluation typically shows features of osteomalacia: low vitamin D, hypocalcemia or hypophosphatemia, and elevated alkaline phosphatase.

Management targets the underlying cause: vitamin D and calcium supplementation, dietary optimization, and treatment of any renal or malabsorptive problems. As mineralization improves, symptoms diminish and radiographic lines may gradually heal over months.