| Forearm function plays an important role in daily life,work,fitness and entertainment.Fractures of the forearm caused by trauma were common,accounting for 11.20%.Treatment of the fracture requires reconstruction of the length of the ulnar radius,alignment,and rotation to achieve good forearm function.Conservative treatment is appropriate for patients with poor baseline conditions.External fixation often results in failure,infection,and poor healing.Miniature intramedullary nail and plate are common internal fixation methods in clinic.Open reduction plate screw fixation is a classic operation.Benefits of steel plate:Anatomical reduction was achieved under open surgery.Strong pressure fixation provides stability for early rehabilitation exercise.Fractures involving the articular surface and distal and proximal diaphysis can be treated.No special conditions,long-term retention after surgery.There are also disadvantages in choosing plate internal fixation:It is necessary to fully expose the operative field.There are large soft tissue damage,more periosteum stripping,and reduced blood supply at the fracture end.Eccentric fixation resulted in the reduction of bone under steel plate under stress stimulation and osteoporosis in fixed segment.After removal of the plate,the screw hole left behind is at risk of re-fracture.Miniature intramedullary nails have the following advantages:Most fractures are closed reduction and fixation,with little interference to blood circulation.Limited incision results in less skin and soft tissue damage,lower risk of postoperative wound infection,and less residual scars.This caters to patients' requirements for postoperative aesthetics,and alleviates the psychological and spiritual impact of trauma on patients.The intramedullary central type is fixed,reducing stress shielding.Elastic fixation,fracture end mechanical stimulation,conducive to the formation of callus.Secondary removal,it is small damage to bone and easy to pull out.The method has some shortcomings:It is not suitable for proximal and distal ulna fractures.If closed and difficult to reset,a new incision is required to reset.Fixed strength is poor,early postoperative for functional exercise often need auxiliary fixation.If intramedullary nail length discomfort,it may enter the ulnar bone.When the distal is locked,there is a risk of ulnar artery and ulnar nerve collateral damage.About fracture management,Palmer points to a balance between securing stability and protecting soft tissue.These two kinds of internal fixation in the treatment of ulna fracture have their own characteristics.But the choice of the best method is controversial.The analysis of ulna biomechanics from the perspective of finite element analysis is rarely reported.Considering the biological and mechanical factors of bone,this study compared two kinds of internal fixation in terms of clinical efficacy and finite element biomechanics,so as to provide a reference for clinical practice.Part?:comparison of clinical effect between miniature intramedullary nail and plate in the treatment of ulna fractureObjective:For clinical reference,To compare the effect of miniature intramedullary nail and plate in the treatment of ulna fracture.Methods:From October 2015 to October 2019,A retrospective study was conducted on 69 patients with ulnar fracture of forearm admitted to the department of orthopedics of our hospital,divided into groups A and B.Patients with combined radius were fixed with plates.The ulna patients in group A were the miniature intramedullary nail group,with A total of 35 cases,and 27 cases with radial fracture.Ulna patients in group B were plate group,a total of 34 cases,and 27 cases were combined with radial fracture.The operation time,intraoperative blood loss,fracture healing time,incision length in the ulna surgical area,incidence of postoperative complications,excellent and good rate of forearm rotation function and other indicators were counted to evaluate the clinical efficacy of two kinds of internal fixation.Results:Clinical indicators: the average operation time of group A and group B was 46.30±6.46 minutes,64.53±7.53 minutes,the average intraoperative bleeding was 23.40±3.74 ml,53.31±6.56 ml,the average fracture healing time was 11.60±0.87 weeks,14.69±1.47 weeks,and the average incision length was 4.52±0.44 cm,10.55±0.65 cm.In terms of the above,the t values between the two groups were-10.81,-23.17,-10.58,and-45.15,respectively,with P values < 0.05,indicating statistically significant differences.Group A was considered to be superior to group B in the above indicators.The number of complications in group A was 3,with an incidence of 8.57%;the number of complications in group B was 4,with an incidence of 11.76%.Anderson of the forearm rated 30 cases of excellent in group A,accounting for 85.71%,and 28 cases of excellent in group B,accounting for 82.35%.The above comparison showed no statistical significance.Conclusion:In the treatment of ulnar fractures,the excellent rate of forearm rotation function and the incidence of postoperative complications were similar in the treatment effect of miniature intramedullary nail and plate.However,in terms of operation time,intraoperative bleeding,fracture healing,and incision length at the ulnar surgery area,the miniature intramedullary nail is better than the plate,which is more consistent with the concept of ERAS(Enhanced Recovery After Surgery).Part ?: the biomechanical analysis of the treatment of ulna fracture with miniature intramedullary nail and plateObjective:With the help of finite element analysis,the differences in biomechanics between miniature intramedullary nail and plate in the treatment of A1.2 ulnar diaphysis fracture,were analyzed,providing a reference for clinical treatment.Methods:The full-length CT scan of the ulna of the forearm was performed in a normal adult female volunteer.The ulna was extracted by MIMICS 17.0 software with the help of threshold segmentation,interest region extraction,region growth,model editing and other functions,so as to reconstruct the normal and complete ulna geometric model.The data exported above were processed by Geomagic Studio 2012 software to optimize the shape,establish the model of ulnar shaft transverse fracture,and perform the internal fixation assembly according to the operation manual of internal fixation.Hypermesh 13.0 software was used to divide the mesh and assign the property according to the bone density value obtained by CT.Determine the boundary conditions,use the finite element analysis software Abaqus 6.14 to carry out load loading.The stress distribution characteristics and displacement changes of different models under the same load are analyzed,and the fixed objects with better mechanical properties are obtained.Results:Under the condition of phase coaxial and torsional loading,the stress distribution of the two internal fixation systems was consistent with that of the normal ulna model,and decreased from the distal ulna to the proximal ulna.The stress distribution around fracture in plate model is larger than that of miniature intramedullary nail.Steel plate larger in the term of axial compression and maximum tension.Under the same torque,the stress distribution of the miniature intramedullary nail model was consistent with that of the normal ulna model.The stress of steel plate model is concentrated on the side of steel plate.The maximum torque load of miniature intramedullary nail is smaller than that of steel plate.The stress of miniature intramedullary nail was uniform under different loading conditions.Stress concentration in the middle of the plate(near the fracture).Under the condition of phase coaxial loading,the displacement distribution of the two internal fixation models was consistent with that of the normal ulna,and the displacement decreased from the distal ulna to the proximal ulna,and the maximum value was located at the distal ulna.The maximum values of the three groups of models are similar in axial compression.The maximum axial pull displacement of the miniature intramedullary nail was similar to that of the normal ulna,and smaller than that of the plate.Under the same torsional loading condition,the displacement distribution of the miniature intramedullary nail model at both ends of the fracture was consistent with that of the normal ulna.The displacement distribution of the plate model showed that the distal fracture was significantly larger than the first two models,and there was no significant difference in the proximal fracture.The results showed that the miniature intramedullary nail was similar to the normal ulna,and the plate model was significantly larger than the miniature intramedullary nail model.Conclusion:Through the finite element model analysis,this type of fracture was treated with stress comparison,axial compression and tension resistance,and better mechanical properties of the steel plate.Torsion resistance,micro intramedullary nail mechanics better.Compared with the displacement,the miniature intramedullary nail is more consistent with the normal ulna mechanical structure. |
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