Prevalence of radiographic findings consistent with femoroacetabular impingement in military personnel with femoral neck stress fractures.

A femoral neck stress fracture is a serious condition that affects military personnel and endurance athletes. There is increasing evidence that femoroacetabular impingement contributes to significant hip pathology. This study investigates the prevalence of radiographic abnormalities associated with impingement in military personnel treated for femoral neck stress fractures. The radiographs of 69 consecutive soldiers being treated for a femoral neck stress fracture identified on magnetic resonance imaging were reviewed for radiographic signs of femoroacetabular impingement. In the cohort, the average incidence of a crossover sign was 51% (27/53). The incidence of a center edge angle greater than 40° was 47% (25/53). The alpha angle was greater than 50° in 55% (29/53). In conclusion, it appears that young patients with femoral neck stress fractures have a high prevalence of radiographic abnormalities suggestive of hip impingement. Hip impingement may lead to abnormal stress across the femoral neck, predisposing individuals to stress fractures.