Ji Songjie, Huang Ye, Zhou Yixin, Wang Chao, Wang Xiaokai, Ma Chaoyi, Jiang Xu
Department of Orthopedic Surgery, Beijing Jishuitan Hospital, Fourth Clinical College of Peking University, Beijing, China.
Department of Statistics, Beijing Research Institute of Traumatology and Orthopedics, Beijing, China.
Front Surg. 2023 Jan 9;9:1054351. doi: 10.3389/fsurg.2022.1054351. eCollection 2022.
Residual varus after Oxford unicompartmental knee arthroplasty (UKA) happens frequently. This study aims to evaluate the pre-operative contributing factors of residual varus.
A total of 1,002 knees (880 patients, 201 patients were male, and 679 were female) underwent Oxford UKA in the Orthopedic Surgery Department of the Beijing Jishuitan Hospital from March 2018 to April 2021. The mean age of the patient was 64.7 ± 7.7 years. To assess residual varus, the full-length lower extremity is placed upright for EOS imaging, with the knee fully extended. The angle of post-operative residual varus was measured as described by Noyes . Of the knees studied, they were either categorized into an under-corrected group (post-operative Noyes angle >5°) or a corrected group (post-operative Noyes angle ≤5°). Age, gender, body mass index (BMI), range of motion (ROM), Clinical American Knee Society Score (Clinical AKSS), and Function American Knee Society Score (Function AKSS) were compared. The following additional parameters were measured: pre-operative Noyes angle, lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), the posterior slope of the proximal tibia angle (PPTA), joint line converge angle (JLCA), and fixed flexion deformity (FFD).
There was no statistically significant difference between the two groups in regards to gender ( = 0.428), surgical leg ( = 0.937), age ( = 0.851), BMI ( = 0.064), pre-operative Clinical AKSS ( = 0.206) and Function AKSS ( = 0.100). However, pre-operative ROM statistically differed between the two groups ( < 0.001). The contributing factors of post-operative residual varus were determined to be the following parameters: pre-operative MPTA ( < 0.001, OR = 4.522, 95% CI: 2.927-6.984), pre-operative Noyes ( < 0.001, OR = 3.262, 95% CI: 1.802-5.907) and pre-operative FFD ( = 0.007, OR = 1.862, 95% CI: 1.182-2.934). The effects of pre-operative LDFA ( = 0.146), JLCA ( = 0.942), and pre-operative PPTA ( = 0.899) on the post-operative mechanical axis did not show statistical significance.
Patients with severe pre-operative varus, particularly varus deformity mainly from the tibial side or pre-operative FFD, are more prone to get extremity mechanical axis residual varus after UKA with Oxford.
牛津单髁膝关节置换术（UKA）后残留内翻畸形的情况较为常见。本研究旨在评估术前导致残留内翻的相关因素。
2018年3月至2021年4月，北京积水潭医院骨科共对1002例膝关节（880例患者，其中男性201例，女性679例）进行了牛津UKA手术。患者的平均年龄为64.7±7.7岁。为评估残留内翻情况，将下肢全长直立位进行EOS成像，膝关节完全伸直。术后残留内翻角度按照诺伊斯（Noyes）的方法进行测量。在所研究的膝关节中，将其分为矫正不足组（术后诺伊斯角>5°）或矫正良好组（术后诺伊斯角≤5°）。比较两组患者的年龄、性别、体重指数（BMI）、活动范围（ROM）、美国膝关节协会临床评分（Clinical AKSS）和美国膝关节协会功能评分（Function AKSS）。还测量了以下额外参数：术前诺伊斯角、股骨远端外侧角（LDFA）、胫骨近端内侧角（MPTA）、胫骨近端后倾角（PPTA）、关节线汇聚角（JLCA）和固定屈曲畸形（FFD）。
两组在性别（P = 0.428）、手术侧（P = 0.937）、年龄（P = 0.851）、BMI（P = 0.064）、术前Clinical AKSS（P = 0.206）和Function AKSS（P = 0.100）方面差异无统计学意义。然而，两组术前ROM差异有统计学意义（P < 0.001）。术后残留内翻的相关因素确定为以下参数：术前MPTA（P < 0.001，OR = 4.522，95%CI：2.927 - 6.984）、术前诺伊斯角（P < 0.001，OR = 3.262，95%CI：1.802 - 5.907）和术前FFD（P = 0.007，OR = 1.862，95%CI：1.182 - 2.934）。术前LDFA（P = 0.146）、JLCA（P = 0.942）和术前PPTA（P = 0.899）对术后力学轴线的影响无统计学意义。
术前存在严重内翻畸形，尤其是主要源于胫骨侧的内翻畸形或术前FFD的患者，在接受牛津UKA术后更易出现下肢力学轴线残留内翻。
