Résumé : Treatment of complex fractures of the proximal humerus is still controversial. This prospective study was designed to evaluate the results of open reduction and proximal nailing in complex fractures of the proximal humerus. Fifteen patients aged 39 to 83 years (average: 59 years) presenting severely displaced fractures of the proximal humerus were observed after open reduction and fixation by proximal nailing (Telegraph) combined with screwing and/or osteosuture of the tuberosities. The patients were evaluated at one year clinically and radiologically. The Constant score, DASH score and Simple Shoulder Test were calculated. Complementarily, patients were submitted to an isokinetic test. At one year follow-up, the average range of motion was 85 degrees (40 degrees-170 degrees) for elevation, 82 degrees (40 degrees-170 degrees) for abduction, L3 for internal rotation and 34 degrees (10-60 degrees) for external rotation. The average visual analog score was 3 points (0-8 points). The Constant score varied from 17 to 92 points (average: 48 points). Isokinetic evaluation showed mostly a strength deficit in abduction even for patients presenting an excellent result. Functional results were related to the quality of the surgical reduction but also to patients' collaboration. Various treatment methods for complex fracture of the proximal humerus are reported in the literature. When a nearly anatomical reduction is achieved, the here-described method of open reduction and proximal nailing permits to obtain good functional results in most patients. This option should be considered for young patients and even in the elderly where results are comparable to that obtained with hemiarthroplasty in the same condition.