| Purpose:At present,cannulated screws or plates are commonly used to treat coronal fractures of the distal humerus,but the therapeutic effects of both are still insufficient.In order to seek a better treatment for coronal fractures of the distal humerus,this experiment used 3D printing to establish isometric fracture reduction models,preoperative simulation of surgical operations,and personalized customized steel plates to provide a potential treatment method for the treatment of coronal fractures of the distal humerus,and then to provide a research basis for optimizing the clinical treatment effect of coronal fractures of the distal humerus.Method:（Ⅰ）Biomechanical experimentThe biomechanical experiment is divided into two parts: model bone experiment and cadaveric bone experiment.Firstly,the model bone experiment was used for preliminary screening,and the screw space configuration with the best mechanical strength was selected for the cadaveric bone experiment.（1）Biomechanical experiment of model boneThe specimens used in the model bone experiment were artificial model humerus,with a total of 12 roots.They were divided into three groups according to the principle of random: anterior parallel group,anterior cross group and posterior cross group.Mechanical tests were performed on the specimens using a universal testing machine.The obtained data of 75 N displacement value,axial stiffness and ultimate load were analyzed and compared,and the screw configuration with the best biomechanical strength was selected for the next biomechanical experiment of cadaveric bone.（2）Biomechanical experiment of cadaveric boneThe experimental materials used in the cadaveric bone experiment were 16 embalmed cadaveric bones obtained after screening and exclusion.The embalmed cadaveric bones were randomly divided into four groups according to the internal fixation method: Herbert screw group,ordinary plate group,custom plate group,and custom plate combined with Herbert screw group.Mechanical testing of the samples was performed using a universal testing machine.The resulting data for75 N displacement,axial stiffness,and ultimate load were analyzed and compared.（Ⅱ）Retrospective analysis of clinical dataIn this study,24 patients with coronal fractures of the distal humerus who underwent surgical treatment at the Department of Orthopaedic Trauma,× ×Hospital from January 2019 to December 2021 were retrospectively analyzed and combined with inclusion and exclusion criteria.Among them,there were 14 cases in the Herbert screw internal fixation group,and 10 cases in the custom plate combined with Herbert screw internal fixation group.The differences in operation time,intraoperative blood loss,incision length,and Mayo score of elbow joint function at 3 months after operation were compared.Result:（Ⅰ）Biomechanical experiment（1）Biomechanical experiment of model boneAspects of displacement between fracture ends under a load of 75 N.There was no significant difference in the degree of displacement between the fracture ends of the three groups（P > 0.05）.Ultimate load: The ultimate load of the front cross group and the back cross group was higher than that of the front parallel group（P < 0.05）.Axial stiffness: the axial stiffness of the front cross group and the back cross group was higher than that of the front parallel group（P < 0.05）.The results of the model bone experiment showed that the biomechanical strength of the anterior cross group and the posterior cross group was higher than that of the anterior parallel group.Although the three measurement indicators of the front cross group and the back cross group were not statistically significant,it was found that the biomechanical strength of the front cross group was slightly better than that of the back cross group.In addition,considering factors such as actual surgical operations in clinical practice,the anterior cross group is more common.Therefore,we chose the screw configuration of the anterior cross group to conduct the cadaveric bone experiment.（2）Biomechanical experiment of cadaveric boneDisplacement between fracture ends under a load of 75 N: the displacement of the custom-made plate combined with Herbert screw group was smaller than that of the ordinary plate group and the Herbert screw group（P < 0.05）.There was no significant difference in the displacement value between the custom plate combined with Herbert screw group and the custom plate group（P > 0.05）,and there was no significant difference in the displacement values between the custom-made steel plate group,the ordinary steel plate group and the Herbert screw group（P > 0.05）.Ultimate load: The ultimate load of the customized steel plate combined with Herbert screw group was higher than that of the customized steel plate group,ordinary steel plate group and Herbert screw group（P < 0.05）.Axial stiffness: the axial stiffness of the custom-made steel plate combined with Herbert screw group was higher than that of the custom-made steel plate group,the ordinary steel plate group and the Herbert screw group（P < 0.05）.（Ⅱ）Retrospective analysis of clinical dataA retrospective analysis of 24 patients with coronal fractures of the distal humerus showed no significant difference in operation time,intraoperative blood loss and incision length between the two groups（P > 0.05）.Three months after operation,the Mayo score of elbow joint function in the custom plate combined with Herbert screw group was better than that in the Herbert screw group（P < 0.05）.Conclusion:1.Cross screw placement is better than parallel screw placement When the screws are in a plane perpendicular to the fracture line,,and custom-made steel plates combined with Herbert screws have the strongest mechanical strength.2.Compared with screw fixation alone,the use of individualized customized steel plate combined with Herbert screw achieved better clinical treatment effect without increasing the operation time,intraoperative blood loss and surgical difficulty.3.In the clinical treatment of coronal fractures of the distal humerus,the plate is customized according to the patient’s own bone structure and fracture characteristics,and combined with Herbert screws to firmly fix the distal coronal fractures to achieve safe and effective early functional exercise and reduce postoperative complications.This would be a more reliable potential treatment for coronal fractures of the distal humerus. |
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