Imageological study of rotational alignment reference landmarks of the proximal tibia in total knee arthroplasty / 中华骨科杂志

ABSTRACT

Objective To investigate the role of rotational alignment reference landmarks of the proximal tibia in total knee arthroplasty.Methods Fifteen healthy adult volunteers were enrolled in this study,including 10 males and 5 females,aged from 21 to 38 years (average,28.1±6.0).CT scans of 26 knees were taken as the knees were placed in full extension.Two anteroposterior axes were drawn on the CT imagesone line connected the middle of the posterior cruciate ligament insertion site and the medial edge of the patellar tendon,and another line connected the middle of the posterior cruciate ligament insertion site and the middle-medial 1/3 of the patellar tendon.The surgical epicondylar axis was also drawn on the CT images.Angles were measured between a line perpendicular to the surgical epicondylar axis and the two anteroposterior axes,and the angles were compared with the ideal tibial rotational alignment reference axis (0°).Results Angles between the line perpendicular to the surgical epicondylar axis and the line connecting the middle of the posterior cruciate ligament insertion site and the medial edge of the patellar tendon averaged 0.7°±2.8° (range,-5.1°-5.8°),there was no significant difference compared with 0°.Angles between the line perpendicular to the surgical epicondylar axis and the line connecting the middle of the posterior cruciate ligament insertion site and the middle-medial 1/3 of the patellar tendon averaged 6.9°±5.3° (range,-3.4°-14.1°),there was significant difference compared with 0°.Significant difference existed in angles between the two anteroposterior axes and the line perpendicular to the surgical epicondylar axis.Conclusion The line connecting the middle of the posterior cruciate ligament insertion site and the medial edge of the patellar tendon is a more reliable reference axis for the tibial component rotational alignment,which makes the femoral and tibial components in a more matching rotational position.