Stress fracture

Stress fracture (from English stress — strain, pressure, load) is a compromise in the structural integrity of the bone that arises not from a single acute trauma but from recurrent, cyclic mechanical loading.

It is a microtraumatic injury exceeding the natural reparative capacity of bone tissue.

Etiology and pathophysiology

The pathogenesis is based on a gross disruption of the normal bone remodeling process. Activity of cells that break down old bone tissue for its renewal temporarily exceeds the activity of cells that form new bone. As a result, osseous trabeculae fail to recover quickly after the load.

Multiple microfractures begin to accumulate in the bone, which over time coalesce into a single linear fracture. In the context of pelvic injuries, sacral stress fractures in the elderly hold a particular significance. They frequently occur against a backdrop of marked osteoporosis even during normal walking, where the fragile bone simply cannot support the patient’s own body weight.

Clinical significance

The most insidious feature of the pathology is its gradual and unnoticed onset. Pain appears exclusively during physical exertion and completely dissipates at rest, but gradually and persistently progresses over time to become constant. Swelling is usually localized, without the formation of a typical hematoma.

In the early stages (within the first few weeks), such fractures often remain invisible on standard radiographs. The gold standard for early diagnosis is magnetic resonance imaging, which clearly shows bone marrow edema. The treatment is conservative and requires prolonged unloading of the affected limb using crutches.