OBJECTIVE: External fixation has been advocated as an alternative treatment method of intertrochanteric fractures in elderly and high-risk patients. However, the efficacy of the technique in all fracture types has not been clearly defined. The null hypothesis of this study was that external fixation showed equal results in either stable or unstable intertrochanteric fractures in patients older than 75 years of age.DESIGN: Prospective comparative study.SETTING: Level I trauma center.PATIENTS: Between July 2006 and June 2007, 100 patients older than 75 years of age (mean, 82.3 ± 5.2 years) and American Society of Anesthesiologists 3 or 4 who sustained an isolated intertrochanteric fracture met the inclusion criteria for the study. The patients were followed up at regular intervals until 1 year postoperatively.INTERVENTION: All fractures were stabilized with external fixation under epidural anaesthesia. The patients were divided in two groups according to the Orthopaedic Trauma Association classification system for intertrochanteric fractures. Types A1.1, A1.2, A1.3, and A2.1 fractures were considered stable (Group A) and Types A2.2, A2.3, A3.1, A.3.2, and A.3.3 unstable (Group B). Fifty patients were collected in each group.MAIN OUTCOME MEASUREMENTS: Operation and hospitalization time, union time, complication rate, Harris hip score, and patients' walking status were evaluated.RESULTS: The median operative time was 17 minutes (range, 15-50 minutes) in Group A and 21.5 minutes (range, 15-60 minutes) in Group B (P < 0.001). The median hospitalization time was 5 days (range, 2-11 days) in Group A and 7 days (range, 4-17 days) in Group B (P < 0.001). The average union time was 11.24 ± 1.66 weeks (range, 9-16 weeks) for Group A and 14.1 ± 1.63 weeks (range, 10-17 weeks) for Group B (P < 0.001). The overall complication rate was 8% for the stable fractures and 26% for the unstable fractures (P = 0.03). The rate of varus collapse in unstable fractures was 11%. The median Harris hip score was 75 points (range, 28-100) in Group A and 68 points (range, 25-99) in Group B (P = 0.006). No difference was found between groups in terms of mortality (P = 0.913) or walking status (P = 0.736).CONCLUSION: External fixation for the treatment of Orthopaedic Trauma Association Types A2.2, A2.3, A3.1, A.3.2, and A.3.3 intertrochanteric fractures in the elderly was associated with prolonged union time, increased incidence of varus position of the fracture site, and inferior functional outcome. Therefore, it should be used with caution in the geriatric population with an unstable intertrochanteric fracture.