Clinical Observation And Biomechanical Study Of Small Splint For Distal Radius Fracture

Objective: To investigate the effectiveness and advantages of small splint fixation of distal radius fractures by observing the clinical efficacy of small splint fixation and finite element analysis of mechanical characteristics of small splint fixation.Methods: 1.Clinical study: 60 elderly patients with Colles fracture aged from 60 to 85 years old were observed from October 2019 to October 2020 in the department of Orthopaedic Trauma of The Affiliated Hospital of Shandong University of Traditional Chinese Medicine and the department of Orthopaedic Trauma of the Affiliated Hospital of Shandong University of Traditional Chinese Medicine.The patients were randomly divided into two groups by a coin toss,which were treated with closed reduction small splint external fixation and plaster external fixation.Fracture healing time and recovery of wrist joint function were observed and recorded in the two groups.Palmar Angle,ulnar Angle,styloid height and postoperative complications of distal radius after reduction;Wrist function was evaluated by the wrist Cooney score.2.Biomechanical research:(1)Model establishment and verification The WRIST CT scan data of healthy volunteers were selected,and the 3D geometric model of wrist was established by importing Mimics21.0 image processing software in DICOM format,and the model was imported into 3-Matic software for surface mesh optimization model.The material properties and boundary conditions were set in ANSYS software.The bottom of the radius was fixed,and a maximum biological axial force of 100 N was added above the carpal bone,which was compared with the results of cadaver experiments in literature to verify the accuracy of the model.(2)Model simulation in Solid Works software according to the colles fracture morphology assembly,segmentation,division of fracture line,according to the fracture line and the radial vertical axis of the Angle,established 15°,30°,45° three Colles fracture morphology model.A pressure of 28 k Pa was applied around the wrist to simulate the model with splint fixation of three fracture patterns.(3)A maximum biological axial force of 100 N was applied to the radial articular surface of each model.The simulation results of each model were collected and discussed.Results: All patients were followed up for 12 months and recovered.The healing time of splint group was shorter than plaster group,and the difference was statistically significant(P<0.05).Cooney score of wrist function immediately after removal of external fixation and 3 months after reduction showed that splint fixation was better than plaster fixation,with statistically significant difference(P<0.05).There was no significant difference in Cooney score between the two groups at 6 months and 1 year after reduction(P>0.05).There was no significant difference in imaging between the two groups immediately after reduction,1 month after reduction,and 3months after reduction(P>0.05).In terms of postoperative complications,there were 2 blisters in the splint group and 8 wrist stiffness in the plaster group after reduction,and the complications in the plaster group were more than those in the splint group,with statistical significance(P<0.05).Finite element analysis of 15° fracture line model shows that without splint fixation,the maximum displacement of fracture model is 1.08 mm,the maximum stress occurs at the fracture,the stress is 4.35 mpa.After splinting,the maximum displacement of radius was 0.25 mm in the fracture model and 0.69 mm in the whole model,and the effective rate of splinting was 76.85%.The maximum stress was still at the fracture site,but the stress was reduced to 1.63 mpa.In the 30° fracture line model,the maximum displacement and stress in the fracture model were 1.12 mm and 7.68 mpa without splint.After splinting,the maximum displacement of radius in the fracture model was 0.35 mm,the maximum displacement of the whole model was 0.72 mm,the effective rate of splinting was 68.75%,and the stress was reduced to 4.62 MPa.45° fracture line model,without splint,the maximum displacement in the fracture model is 1.17 mm,the maximum stress occurs at the fracture,the stress is 8.94mpa;After splinting,the maximum displacement of radius in the fracture model was 0.37 mm and the maximum displacement of the whole model was 0.75 mm.The effective rate of splinting was 68.37% and the stress was reduced to 4.97 MPa.In addition,the stress in most areas of the three fracture line models after splint fixation is less than 2MPa.Conclusion: Traditional Chinese medicine small splint fixation can meet the requirements of fracture fixation,and is beneficial to the functional rehabilitation of wrist joint,simple operation,low cost,suitable for clinical development and promotion.