Fatigue Fracture of the Femoral Neck

Forty-one fatigue fractures of the femoral neck in thirty-six patients are presented and analyzed. All occurred in men undergoing the first eight weeks of basic infantry training (with an average age of twenty-two and one-half years). The right hip was involved in eighteen patients and the left in thirteen; five had bilateral fractures. No definite relationship could be established between occurrence of fractures and length of training. Pain and stiffness in the hip region were almost always present and had lasted from one day to four weeks (generally five to ten days) prior to entry into the hospital. In those cases in which displacement occurred, there was sudden, severe pain with collapse and, generally, inability to bear weight. Most patients were found to have a limp or antalgic gait, limitation of hip motion (especially internal rotation and flexion) due to pain, and tenderness over the hip joint. Roentgenograms of sixteen femoral necks, obtained on admission of the patients to the hospital, were normal. In this group, selerosis was demonstrated one to four weeks after onset of symptoms in fourteen cases, and in three Patients fractures developed across the neck; two of these three fractures later became displaced. Sclerosis was present on admission in eleven femoral necks; in one of these a fracture line developed in three weeks. In six, there was a small calcar crack or fracture line across the neck, without displacement, and there were seven cases of displaced fracture demonstrated roentgenographically on admission. Treatment for Type I (twenty-four fractures) was conservative, consisting in bed rest followed by progressive weight-hearing. For Type II (eight fractures), treatment was also generally conservative but did include plaster immobilization and, in one case, internal fixation. In Type III (nine fractures), internal fixation was employed. In this group complications were frequent and consisted of malunion, nonunion, and avascular necrosis; in fact, in only two of these fractures did union occur initially. This course of events is attributed to poor reduction and to the nature of the fracture, which occurs in markedly osteoporotic bone. Average hospitalization of patients with Type I fractures was nine and one-half weeks; of those with Type II fractures, twelve weeks; and of those with Type III fractures, fifty-nine weeks. The term fatigue fracture may be misleading in that frequently no overt fracture line is seen. Fatigue (or stress) fracture is actually a process, an alteration of hone resulting from stress. A fracture may or may not develop, and if it does it can be considered as a complication of the stress reaction. (For simplicity, the term fatigue fracture is used throughout this paper, with the above reservation.) It seems reasonable to assume that the occurrence of fatigue fractures is not confined to military life. The overweight white-collar worker who goes on a strenuous fishing or hunting trip or starts on a program of vigorous exercise may well incur a fatigue fracture. The teenage athlete who pushes himself to the maximum at the start of the season and the less athletically inclined student who strives to do well in a physical fitness program are both prime candidates for these fractures. Unless the physician is sufficiently aware of the possibility that a fatigue fracture may have occurred, serial roentgenograms are not made and such a fracture remains undiagnosed. Generally, this is not a serious consequence with fatigue fractures of the foot or leg unless they are mistakenly treated as neoplasms. However, if those in the femoral neck are overlooked or misdiagnosed, serious sequelae, as previously illustrated, may result.