| Chapter 1 Anatomy of lateral collateral ligament complex of the elbow OBJECTIVE: To observe the composition of the lateral collateral ligament complex of the elbow joint and provide anatomical basis for the repair and reconstruction of the injury of the lateral collateral ligament of the elbow joint.METHODS: 15 adult elbow specimens preserved in formalin solution were dissected to obtain the lateral collateral ligament complex of elbow joint,and the starting and ending points and adjacent relations of each ligament were observed.The length and width of the lateral ulnar collateral ligament were measured with vernier caliper,and the angle between the lateral ulnar collateral ligament and the long axis of humerus was measured with protractor when the elbow joint was extended.Repeat the measurement 3 times for each group,and record the average value of the measurement.RESULTS: The lateral collateral ligament complex was composed of radial collateral ligament,annular ligament and lateral ulnar collateral ligament,and the boundary between them was not clear.During elbow flexion and extension,the length of the lateral collateral ligament changed with the elbow flexion and extension,LUCL did not show true isometry.When elbow flexion was 0,30,60 and 90 degrees,the length of the anterior margin of lateral ulnar collateralligament was(35.1±3.3)mm,(32.4±3.1)mm,(33.9±3.4)mm,(33.1±2.9)mm.The length of the posterior margin of LUCL was(28.6±2.7)mm,(33.8±3.5)mm,(33.1±3.0)mm,(33.4±3.3)mm.Width of LUCL's origin was(4.2±0.4)mm,(4.2±0.3)mm,(4.0±0.3)mm,(3.9±0.3)mm;and width of LUCL's insertion was(8.3±0.4)mm,(8.3±0.3)mm,(8.2±0.3)mm,(8.2±0.4)mm.The angle between the lateral ulnar collateral ligament and the long axis of the humerus was 23±1.9 °in the elbow extension position.CONCLUSION: The length of the lateral ulnar collateral ligament changes with the flexion angle of the elbow joint,and it is not isometric in flexion and extension.Chapter 2 Comparison of the display effect of oblique coronal view with different angles on lateral collateral ligament of elbow joint on MRI OBJECTIVE: To compare the display effect of lateral ulnar collateral ligament and radial collateral ligament of elbow joint on oblique coronal plane with different tilt angles on MRI,and to find the best display section,so as to provide basis for better evaluation of lateral collateral ligament.METHODS: 16 healthy volunteers were examined by MRI of elbow joint,11 males and 5 females,with an average age of 29.8 years(19-43 years),13 on the right side and 3 on the left side.No abnormal bone structure was found by X-ray examination of elbow joint.The position of MRI was supine,the elbow joint was extended and fixed.Using the avanto 1.5-T superconductive Mrmachine of Siemens company,16 volunteers elbow joints were scanned by MRI.The angle between elbow joint and long axis of humerus was 0 °,10 °,23 ° and30 °.By using the 5-point system,two doctors scored the quality of the lateral collateral ligament on the oblique coronal plane at different angles,and compared the display effect of the ligaments on the oblique coronal plane at different angles.RESULTS: The total length of ligaments in 23 ° oblique coronal position was more than that in other oblique coronal positions.At 23 ° oblique coronal position,there was a good correlation between the two observers.On the oblique coronal position of different angles,MR imaging of elbow joint of most volunteers showed that the radial collateral ligament showed the full length and the starting and ending points of the ligament on at least one level.CONCLUSION: When MRI was used to evaluate the lateral ligament of elbow joint,the effect of showing the lateral ulnar collateral ligament on 23 °oblique coronal position was better than that on other oblique coronal positions;the radial collateral ligament could be shown on different oblique coronal positions.Chapter 3 Establishment of three dimensional finite element model of elbow joint OBJECTIVE: To establish a three-dimensional finite element model of elbow joint including lower humerus,upper radius,upper ulna,articularcartilage and medial and lateral collateral ligaments,and to verify the validity of the model,so as to provide a research model for further study of lateral collateral ligaments of elbow joint.METHODS: The elbow joint of a healthy male was scanned using computer tomography.The data were imported into MIMICS 16.0 to reconstruct the three-dimensional geometric model of elbow joint,including lower humerus,upper radius,upper ulna,articular cartilage and medial and lateral collateral ligaments.Pre-finite element analysis software is used to smooth the elbow model,simplify the mesh and the number of nodes,and re-divide the surface mesh.The finite element model of the reconstructed elbow joint was analyzed by using finite element analysis software.The force of the elbow joint under the conditions of radial collateral ligament(RCL),lateral ulnar collateral ligament(LUCL)and complete annular ligament(AL)was simulated.The biomechanical properties of the elbow joint were analyzed and calculated.The results were compared with those of the previous published literature and biomechanical tests to verify the validity of the finite element model of the elbow joint.RESULTS: Three-dimensional finite element models of elbow joint,including lower humerus,upper radius,upper ulna,articular cartilage and medial and lateral collateral ligaments,were successfully established by using MIMICS software and finite element analysis software.The validity of the finite element model of elbow joint is verified by comparing with the experimental data in the literature and biomechanical tests.CONCLUSION: The three-dimensional finite element model of elbow joint established in this study can effectively simulate the biomechanical characteristics of elbow joint.Chapter 4 Finite element analysis of deficiency radial collateral ligament,lateral collateral ulnar ligament and annular ligament in elbow model OBJECTIVE :To study the effects of deficiency radial collateral ligament,lateral ulnar collateral ligament and annular ligament of elbow joint on the stability of Posterolateral rotatory instability of the elbow by finite element analysis.METHODS: Based on the established three-dimensional finite element model of elbow joint,the normal and injured models of lateral collateral ligament of elbow joint were simulated and established,which were divided into eight groups: ligament integrity,LUCL resection,RCL resection,AL resection,LUCL+RCL resection,LUCL+AL resection,RCL+AL resection,LUCL+RCL+AL resection,respectively.Axial compression,external rotation and valgus load were applied,and finite element analysis was used to simulate and calculate the models in elbow joint.The stress of ligaments,displacement of radial head and strain of olecranon articular surface of ulna at elbow flexion 45°were compared.RESULTS: When elbow joints were flexed at 45 degrees,when RCL+ AL resection and LUCL was intact,the stress of LUCL increased significantly,with an increase of about 101% relative to that of normal elbow joints;when LUCL+AL resection and RCL was intact,the stress of RCL increased by about42% relative to that of normal elbow joints;when LUCL + RCL resection and AL was intact,the stress of AL increased by about 45% relative to that of normalelbow joints.In the case of AL ligament rupture only,the stress of each ligament,the stress of olecranon joint surface and the displacement of radius head have little influence;when LUCL,RCL and AL are simultaneously ruptured,the stress of olecranon joint surface is about 475 MPa;when LUCL,RCL and AL are simultaneously ruptured,the displacement of the radial head is the most obvious,and the maximum displacement is about 15.1 mm.CONCLUSION: RCL and LUCL play an important role in the stability of the posterolateral rotation of the elbow joint,especially LUCL,which plays a greater role in resisting external rotation and valgus,while LCLC as a whole maintains the stability of the posterolateral rotation of the elbow joint.Chapter 5 Finite element analysis of two reconstruction methods of lateral collateral ligament in elbow model OBJECTIVE: To study and compare the biomechanical characteristics of two reconstruction methods of lateral collateral ligament in elbow model,Docking reconstruction and Yoke reconstruction,using finite element analysis.METHODS: Using the established three-dimensional finite element model of human elbow joint,the ligament reconstruction models of Docking reconstruction technique and Yoke reconstruction technique were simulated and established.The axial load,external rotation moment and valgus moment were given respectively.The stress,radial head displacement and strain of olecranonjoint surface were simulated and calculated by finite element analysis method when the elbow joint flexed 45°,the results were compared.RESULT: When elbow flexion 45°,compared with docking and yoke techniques,it was found that the structural stress of the ligament reconstructed by docking technique was greater than that of yoke technique,and the displacement of the radial head after docking technique reconstructed ligament was also larger than that of yoke operation,about 23%.CONCLUSION: From the mechanical analysis,the stress of the ligament reconstructed by yoke technique is smaller than that of docking technique,which kind of ligament reconstruction technique is better,and further clinical research is needed. |
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