[Stress fractures of the lower leg and foot]

Stress fractures are caused by overstrain. Depending on their etiology, stress fractures may be categorized as insufficiency or fatigue fractures. A fatigue fracture occurs when repeated axial or rotational force is applied to the bone. In contrast, an insufficiency fracture is observed in bones with altered biomechanical characteristics. In a mixed patient population drawn from the Military Hospital Graz and the Unfallkrankenhaus (Traumatological Hospital) Graz, we were able to corroborate these etiologies. At the former institution, all 21 recruits (mean age, 20.5 years) had fractures of the fatigue type. In the population at the Traumatological Hospital--16 patients with a higher average age of 43.5 years--insufficiency fractures predominated. Diagnosis and differential diagnosis proved difficult in both groups, since plain radiography does not demonstrate the fracture for 2-3 weeks after the occurrence. All stress fractures were treated conservatively. Approximately two thirds of all stress fractures occur in the lower extremities. The main age group at risk is unknown. A sudden change in the activity or training regimen or a change in biomechanics can cause a stress fracture. The absence of individual risk factors makes it difficult to prevent stress fractures.