Falls Leading to Femoral Neck Fractures in Lucid Older People

OBJECTIVE: To analyze the mechanisms of falls that result in femoral neck fractures among lucid older people. DESIGN: A cross-sectional study. SETTING: An orthopedic university hospital department. PARTICIPANTS: A consecutive series of 123 lucid patients, 65 years of age or more, who were admitted for femoral neck fractures. MEASUREMENTS: On admission, the subjects were interviewed about fracture accident characteristics, and falling mechanisms were classified. An arterial blood gas sample was taken from each patient soon after admission. Based on data regarding drug consumption and social and medical characteristics, a fall-risk index was calculated for each subject. RESULTS: It was ascertained that 95% of the fractures were caused by falls and < 2% were spontaneous. Most accidents (68%) took place indoors, 47% of the falls were classified as extrinsic, 24% as intrinsic, 7% as nonbipedal, and 22% remained unclassified. Almost all outdoor falls were extrinsic; however, intrinsic falls were as common as extrinsic falls indoors (P < .001). Extrinsic fallers presented a significantly lower fall-risk index score than subjects with fractures caused by intrinsic, nonbipedal, and unclassifiable falls. A large proportion of subjects (24%) wre hypoxemic (pO2 < 8 kPa) on admission, and patients who sustained fractures at night had lower oxygen tension than that of daytime fallers (P = .006). CONCLUSIONS: Accidental falls are the primary cause of femoral neck fractures. Preventive actions should be directed toward intrinsic, as well as extrinsic, risk factors for falls. Hypoxemia might be a risk factor for falls, especially those falls that occur at night.