Classifi cation of stress fractures

Stress fractures represent a fatigue failure of bone, occurring along a spectrum of severity of structural injury with healing potential that varies by location. Many stress fracture classification systems currently exist in the literature. These systems employ various imaging modalities, but few include clinical parameters or have been validated for reliability between evaluators. Though many are generalizable, a gold standard classification system for grading stress fractures has yet to be determined.In order to accurately study and communicate about a pathologic clinical condition, one must be able to accurately describe it. As most clinical pathologies do not exist as a simple “present/not present†entity with a single consistent severity in a consistently equal environment, their description typically requires a classification system. This chapter encompasses the description and classification of stress fractures of bone. In order to understand the rationale behind describing stress fractures a brief review of the pathophysiology of stress fractures will be included. This chapter is divided into the following sections: (1) Defining a Stress Fracture, (2) Features of a Quality Classification System, (3) High-Risk vs. Low-Risk Stress Fractures, (4) Current and Historical Classification Systems, and (5) Kaeding–Miller Classification System.