Department of Orthopaedic Surgery, College of Medicine, Daegu Catholic University Hospital, Daegu, Korea.
J Orthop Surg (Hong Kong). 2020 Jan-Apr;28(2):2309499020926268. doi: 10.1177/2309499020926268.
We have analyzed the surgical outcomes of primary total knee arthroplasty (TKA) using computer-assisted navigation that were performed by a single surgeon in terms of postoperative coronal alignment depending on preoperative varus deformity.
We conducted a retrospective study of patients who have undergone navigated primary TKA from January 2016 through December 2019. Two hundred and fifty-six cases with varus deformity of 10° or less were assigned to group 1, and 216 cases with varus deformity of more than 10° were assigned to group 2. The postoperative mechanical hip-knee-ankle (mHKA) angle was measured from scanograms which were taken preoperatively and 3 months after surgery. The postoperative mHKA angle was targeted to be 0°, and the appropriate range of coronal alignment was set as 0 ± 3°.
The Pearson correlation showed a significant correlation with the degree of preoperative varus deformity and with the absolute error of postoperative mHKA ( = 0.01). Among all patients, 64 cases (13.6%) were detected as outliers (mHKA > 0° ± 3°) at 3 months after surgery. Of the 64 cases, 25 cases (9.8%) were affiliated to group 1 and 39 cases (18.1%) were affiliated to group 2. Group 2 showed significantly higher occurrence of outliers than group 1 ( = 0.01). Multiple variables logistic regression analysis, which analyzed the difference in the occurrence rate of outliers (mHKA > 0° ± 3°), showed that the occurrence rate of group 2 was 2.04 times higher than group 1. After adjusting for patient's age, gender, and body mass index, the occurrence rate of outliers in group 2 was 2.01 times higher than group 1.
The benefit of computer-assisted navigation during TKA in obtaining coronal alignment within 0 ± 3° may be lessened when the preoperative varus deformity is severely advanced.
我们分析了一位医生使用计算机辅助导航进行初次全膝关节置换术（TKA）的手术结果，根据术前的内翻畸形，评估术后冠状面对线情况。
我们对 2016 年 1 月至 2019 年 12 月接受导航初次 TKA 的患者进行了回顾性研究。将内翻畸形 10°或以下的 256 例患者分为组 1，内翻畸形大于 10°的 216 例患者分为组 2。通过术前和术后 3 个月的扫描图测量术后机械髋膝踝角（mHKA）。术后 mHKA 角的目标值为 0°，设定合适的冠状面对线范围为 0 ± 3°。
Pearson 相关分析显示，术前内翻畸形程度与术后 mHKA 的绝对误差呈显著相关（ = 0.01）。所有患者中，术后 3 个月有 64 例（13.6%）mHKA 角大于 0° ± 3°，为离群值。64 例离群值中，组 1 有 25 例（9.8%），组 2 有 39 例（18.1%）。组 2 离群值发生率明显高于组 1（ = 0.01）。对离群值（mHKA > 0° ± 3°）发生率的差异进行多变量逻辑回归分析显示，组 2 的发生率是组 1 的 2.04 倍。在调整患者年龄、性别和体重指数后，组 2 的离群值发生率仍为组 1 的 2.01 倍。
当术前内翻畸形严重时，计算机辅助导航在 TKA 中获得 0 ± 3°冠状面对线的获益可能会降低。
