| Objective:To establish a three-dimensional digital model of the normal adult hand and simulate the subluxation of the first carpometacarpal joint by using MIMICS software,measure the distance between the base of the first and second metacarpal bones of the normal hand and the subluxation model in different positions,and compare the measured data of the subluxation model with the data of the normal model,so as to determine the best X-ray projection position that can accurately evaluate the subluxation of the first carpometacarpal joint,and provide anatomy for clinical diagnosis of the first carpometacarpal joint subluxation Radiological basis.Methods:50 healthy adult volunteers,50 male and 50 female,100 left and 100 right hands were selected for continuous CT scanning with a thickness of 0.625 mm and a spacing of 0.The CT data obtained from the scanning were imported into the MIMICS software to establish a three-dimensional digital model of the hand.After building the 3D model of the hand,first click the "Perspective" option in the "View" to set the model of the hand to 0 °,then click the "Reset" option in the "Alignment",select the first metacarpal bone,and then set it under the "Rotate around the center" option,right hand: "Up" 10 °,"Tilt L" 5 °,"Right" 5 °;Left hand:set "up" 10 °,"tilt R" 5 °,and "leave" 5 ° to simulate the first carpometacarpal joint subluxation,and finally generate the 3D model of the first carpometacarpal joint subluxation hand of both hands.Divide the model into normal hand group and subluxated hand group,display two-dimensional and three-dimensional windows in Mimics software,measure the first and second metacarpal base spacing of the two groups of hands at 0 °(normal position),15 °(tilt15 °),30 °(tilt 30 °),45 °(tilt 45 °),60 °(tilt 60 °),75 °(tilt 75 °),90 °(lateral position),and each data is measured by two people respectively,take the average value,and the measurement result is accurate to 0.01 mm,compare the left and right hands the difference between men and women and between the two groups of hand data from different angles.Results:The digital models of 200 normal hands and 200 first wrist metacarpal joint subluxation hands were established and simulated.Normal hand:According to the measurement and data statistics,the basal distance between the first and second metacarpal bones of the normal hand at 0 ° and 90 °positions is 0 mm,and the gap can be seen at other angles,and it gradually increases from 0 ° to 45 °,and then decreases from 45 ° to 90 °.The values of 0 ° and 90 °,15 °and 75 °,30 ° and 60 ° are the same between different angle groups,and the difference is not statistically significant,while the differences between other groups are statistically significant.Semi-dislocated hand:The gap of the subluxated hand can be seen at all angles,and it also shows the rule of gradually increasing from 0 ° to 45 °,and then decreasing from 45 ° to 90 °.The hand spacing of lower subluxation at the same angle is larger than that of the normal hand,and the difference is statistically significant.There was no statistically significant difference between the left and right hands in the lower subluxation group at the same angle,but there was statistically significant difference between men and women.In the subluxation group,there was no statistically significant difference between two different angles,0 ° and 90 °,15 ° and75 °,30 ° and 60 °,and there was statistically significant difference between two other angles.Conclusion:If the basal space between the first and second metacarpal bones can be seen on the anteroposterior and lateral radiographs of the hand,the subluxation of the first carpometacarpal joint can be diagnosed after excluding other diseases and deformities of the hand.On the oblique X-ray projection of the hand,the basal space between the first and second metacarpal bones can be observed more by tilting 45 °,which has a clear guiding significance for the diagnosis of the subluxation of the first carpometacarpal joint. |
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