Three-dimensional Imaging Study Of Rotational Alignment Of Prosthesis Of Total Knee Arthroplasty

[Objective]Through to the knee CT three-dimensional reconstruction and measurement data,we determined the rotation of the femur and tibia prosthesis for line parameters in the total knee replacement.[Methods]Normal knees of Chinese volunteers were selected for CT scans(including coronal,sagittal,transverse section sequence)from September 2011 to December 2011(without knee osteoarthritis and unstable ligament).We reconstructed three-dimensional CT images through Mimics software for virtual surgery.We determined the planned cutting plane under the high lateral tibia platform 10 mm.We projected STEA,Akagi Line,as well as a line connecting the medial 1/3 of the tibial tubercle and the posterior cruciate ligment insertion(AF)to the planned cutting plane,and compared the angles between Akagi Line,AF,the vertical line of tibial posterior condyle line and STEA.We determined the planned cutting plane under the the femoral condyle 10 mm.We projected STEA,Whiteside Line,femoral posterior condylar line to the planned cutting plane,and compared the angles between STEA,Whiteside Line,femoral posterior condylar line.[Results]The angle between STEA and femoral posterior condylar line was(3.535°± 1.282 4°),ranging from 1.46°to 6.1°.The angle between STEA and Whiteside line was(85.385 3°±2.593 9°),ranging from 80.7°to89.65°.The angle between Akagi line and AP was(0.995 3°±5.4981°),and there was no significant difference between the two lines(P=0.3).The angle between AP and the vertical line of tibial posterior condylar line was(2.507 3°±4.047 4°),and there was a significant difference between the two lines(P=0.002).The angle between AP and AF was(5.623 3°±7.229 8°),and there was a significant difference between the two lines(P=0.000 2).[Conclusion]The average angle between STEA and femoral posterior condylar line was 3.5°.The average angle between STEA and Whiteside line was85.4°.Akagi line was neerly perpendicular to the STEA.Compared with AF and tibial posterior condylar line,Akagi line as a reference axis to guide for rotational alignment of the proximal tibial component was reliable.