Abstract:Objective To assess the clinical and radiological results of fractures of the proximal humerus treated with intramedullary nail fixation and analyze the risk factors associated with a poor outcome.Methods 45 cases of patients with proximal humeral fractures in our hospital from June 2012 to April 2015 were selected as study objects.Patients were analyzed retrospectively with a minimum follow-up of 12~14 months (average 13.1 months).Of all the patients,18 were male and 27 were female.Their age were between 56~74 years old (average 63.8 years).Parameters including operative time and blood loss were recorded.At 1,3,6,12 months after operation,the radiological assessment included AP and axial X-rays in the scapular plane were recorded.Functional outcome of different Neer type fracture were evaluated using the rating scale of the American Shoulder and Elbow Surgeons (ASES),Constant Score,Visual Analogue Scale (VAS) scores and DASH scores.Logistic regression analysis was used to analyze the association between poor outcomes and age,gender,hypertension and other factors.Results All patients completed the follow-up,mean operation time was (126.8±17.2) min and mean blood loss was (173.9±22.1) mL.91.1% of patients were satisfied with treatment.X-rays showed a healing rate of 95.6%,with two cases of pseudarthrosis.At last follow up,the VAS score was (1.6±0.3),ASES score was (85.7±6.0) and Constant Score was (70.8±4.6),DASH score was (15.0±0.9).Mean mobility was (147.6±11.3) ° of fiexion,(33.0±3.2) ° of lateral and (28.4±1.8) ° of medial rotation.Significant differences were found in the Constant score in individuals under 60 years of age (P<0.05).Varus healing was observed in 16 patients (35.6%).Functional differences were found when patients with varus healing were compared with those who had anatomical healing.Age,hypertension and osteoporosis were independent risk factors for adverse outcomes.Conclusion The intramedullary nail fixation is an effective implant for stabilization of displaced proximal humeral fracture with a good functional outcome.Its advantages are short operation time,small incision,less trauma,less blood supply and less complications.Age,hypertension and osteoporosis and other factors may lead to adverse outcomes.