A hairline fracture from repetitive force is called?

• A. Pathologic Fracture
• B. Subluxation
• C. Transverse Fracture
• D. Stress Fracture

Answer: (D)

Repetitive force causes microdamage to bone faster than it can be repaired, leading to a stress fracture. These are tiny, hairline cracks that develop gradually with overuse, such as running or marching with increasing workload. The term stress fracture specifically describes the mechanism—repetitive loading leading to fracture—so it best fits the scenario.

In contrast, a pathologic fracture occurs when disease weakens bone (like osteoporosis or cancer), making it fracture with little or no trauma. Subluxation is a partial dislocation of a joint, not a crack in the bone. A transverse fracture describes a fracture line across the bone, often from a single direct impact, and does not inherently denote a repetitive-stress mechanism.