The Study Of The Curve Of Femur And It's Clinical Application

Objective:To study the normal curve of the femur and it's clinical application.Methods:Collect 51 cases of CT data which include the total femur.Import the CT data into Mimics and rebuild the 3D model and export the model in the pattern of STL.Import the STL profile into Geomagic Studio.Mark 2 points on the femur model as the start point and the end point and pick up the coordinates of these points.Program in the Metalab and import the STL profile to calculate and demonstrate the central point of each plane in femur CT.Name the line composed by the the central point of each plane in femur CT as the central axis of femur shaft.Observe and analyse the form and position of the central axis of femur.Calculate and analyse the central axis of femur as follows:the radius of curvature of the axis,the bending direction position of the axis.We categorized the result into 4 groups according to age and sex and we analyse the similarities and difference between data of these 4 groups.We also analyse the relevance between these data and the age and sex.We simulate the mismatch between the femur prosthesis and the femur in these programs and identify the problems we encountered.Analyse the position of the point which the straight prosthesis is prone to intersect with femur.Propose improvement measures to these clinical problems.Finally,design the femoral prosthesis with curvature and analyse if it match with the virtual femur.Results:The central axis of femur femur shaft is approximate arc shape,the curvature mainly exists in the sagittal plane while the slight curvature exists in the coronal and the horizontal plane.The angle between the central axis of the femur and the front :6.25±0.88° in adult male group,5.99±1.66° in adult female group,5.74±1.03° in underage male group,6.00±0.51° in underage female group6±0.83°and the total average value is 6?00±0.83°.There was no significant difference between groups.The data has no relevancewith the age and sex.The radius of curvature of the axis listed as follows:1149.70±308.56 mm in adult male group,1055.62±293.56 mm in adult female group,1042.37±200.64 mm in underage male group,927.77±257.88 mm in underage female group and the total average value is 1015.10±272.16 mm.There was no significant difference between groups.The data has no relevance with the age and sex According to our results,we can easily calculate the point that the straight prosthesis contact with the front of the femur.The position position of the point which the straight prosthesis is prone to intersect with femur is closely related to the position of osteotomy.Based on our result,we can design the curved femur prosthesis based on the individual data,Conclusion: There is significant curvature in the femur shaft.The central axis is approximate arc shape and the curvature mainly exists in the sagittal plane.There are large difference in the data of the curvature among different individuals.The most protruding point in the axis is near to the middle of it.The mismatch between the femur prosthesis and the femur due to the straight form of the femur prosthesis.Our conclusion is avail to draw up the operation scheme.Using these methods,we can measure and analyse the femur curvature totally and avoid the mismatch between the femur prosthesis and femur by adjusting the osteotomy position and the length of the prosthetic intramedullary stem.Our conclusion is also avail to the design and manufacture of femur prosthesis.If we can design the curved femur prosthesis based on the individual data,the problem of mismatch can be solved perfectly.