The Natural Science Foundation of Jiangsu Province (Grant No. BK20191492)
目的：通过下肢CT图像测量股骨髁通髁轴与股骨后髁轴的旋转度数，为人工全膝关节置换术（Total knee arthroplasty，TKA）术中股骨假体旋转定位提供参考。方法：回顾性分析2018年10月-2022年3月在南京医科大学第一附属医院骨关节外科行TKA手术的283例患者的膝关节X线及下肢CT影像学资料。1名关节外科住院医师及1名资深关节外科主任医师分别通过影像系统测量股骨外科通髁轴（surgical transepicondylar axis，sTEA）及股骨后髁轴（posterior condylar axis，PCA）间夹角度数。计算sTEA与PCA夹角及常规按照PCA外旋3°放置股骨假体TKA术后与sTEA夹角。结果：sTEA相对于PCA平均外旋1.63°（内旋3.79°至外旋7.87°）。常规将股骨假体参照PCA外旋3°放置时，只有163例(57.6%)患者TKA术后股骨假体旋转在sTEA的±2°范围内，其中68例(24%)的患者股骨假体相对于sTEA内旋。结论：膝骨关节炎患者股骨远端旋转存在广泛的差异性，常规参照PCA外旋3°放置股骨假体将会造成显著位置误差，影响TKA预后。关节外科医生应根据术前影像资料个性化制定TKA术中股骨假体旋转力线。
Objective: This study aims to provide references on the rotation of the femoral component during total knee arthroplasty (TKA) by measuring the rotation degree of the surgical transepicondylar axis and the posterior condylar axis of the femoral condyles on CT images. Methods: The X-ray and lower ?extremity CT imaging data of 283 patients who underwent TKA in the Department of Bone and Joint Surgery, the First Affiliated Hospital of Nanjing Medical University from October 2018 to March 2022 were retrospected in our study. One resident and one senior chief physician of joint surgery measured the angle between the surgical transepicondylar axis (sTEA) and the posterior condylar axis (PCA) by the imaging system, respectively. The angle between sTEA and PCA and the angle between femoral component and sTEA after routine placement of the femoral component with reference to 3° external to the PCA was calculated. Results: The sTEA was on average 1.63° externally rotated to the PCA (range 3.79° internal to 7.87° external). When the femoral component was routinely placed at 3 °external to PCA, only 163 (57.6%) patients had femoral component rotation within ± 2 ° of sTEA after TKA, of which 68 (24%) patients had femoral component internal rotation to sTEA. Conclusion: There are extensive differences in the rotation of the distal femur in patients with osteoarthritis. Routinely setting femoral rotation 3° external to the PCA would cause significant position errors in femoral component, affecting the prognosis of TKA. Joint surgeons should individualize the rotational alignment of the femoral component during TKA based on preoperative imaging data.