Objective: To explore the coronal alignment of tibial prosthesis after osteotomy using personalized extramedullary positioning technique on tibia side in total knee arthroplasty (TKA).
Methods: A clinical data of 170 patients (210 knees) who underwent primary TKA between January 2020 and June 2021 and met the selection criteria was retrospectively analyzed. Personalized and traditional extramedullary positioning techniques were used in 93 cases (114 knees, personalized positioning group) and 77 cases (96 knees, traditional positioning group), respectively. The personalized extramedullary positioning was based on the anatomical characteristics of the tibia, a personalized positioning point was selected as the proximal extramedullary positioning point on the articular surface of the tibial plateau. There was no significant difference between the two groups in gender, age, body mass index, surgical side, course of osteoarthritis, and Kellgren-Lawrence classification ( P>0.05). The preoperative tibial bowing angle (TBA) formed by the proximal and distal tibial coronal anatomical axes in the personalized positioning group was measured and the tibia axis was classified, and the distribution of personalized positioning point was analyzed. The pre- and post-operative hip-knee-ankle angle (HKA), the lateral distal tibial angle (LDTA), and the postoperative tibia component angle (TCA), the excellent rate of tibial prosthesis alignment in coronal position were compared between the two groups.
Results: In the personalized positioning group, 58 knees (50.88%) were straight tibia, 35 knees (30.70%) were medial bowing tibia, and 21 knees (18.42%) were lateral bowing tibia. The most positioning points located on the highest point of the lateral intercondylar spine (62.07%) in the straight tibia group, while in the medial bowing tibia and lateral bowing tibia groups, most positioning points located in the area between the medial and lateral intercondylar spines (51.43%) and the lateral slope of the lateral intercondylar spine (57.14%), respectively. The difference in HKA between pre- and post-operation in the two groups was significant ( P<0.05); while the difference in LDTA was not significant ( P>0.05). There was no significant difference in preoperative LDTA and HKA and the difference between pre- and post-operation between groups ( P>0.05). But there was significant difference in postoperative TCA between groups ( P<0.05). The postoperative tibial plateau prosthesis in the traditional positioning group was more prone to varus than the personalized positioning group. The excellent rates of tibial prosthesis alignment in coronal position were 96.5% (110/114) and 87.5% (84/96) in personalized positioning group and traditional positioning group, respectively, showing a significant difference between groups ( χ 2=7.652, P=0.006).
Conclusion: It is feasible to use personalized extramedullary positioning technique for coronal osteotomy on the tibia side in TKA. Compared with the traditional extramedullary positioning technique, the personalized extramedullary positioning technique has a higher excellent rate of tibial prosthesis alignment in coronal position.
目的: 探讨人工全膝关节置换术（total knee arthroplasty，TKA）中应用胫骨侧个性化髓外定位技术截骨后胫骨假体冠状位力线情况。.
方法: 回顾分析2020年1月—2021年6月接受初次TKA且符合选择标准的170例（210膝）患者临床资料。其中，77例（96膝）胫骨侧采用传统髓外定位技术（传统定位组）；93例（114膝）采用个性化髓外定位技术（个性化定位组），即结合胫骨解剖形态特点，在胫骨平台关节面选择个性化定位点作为髓外近端定位点。两组性别、年龄、身体质量指数、侧别、骨关节炎病程及Kellgren-Lawrence分级等一般资料比较，差异均无统计学意义（ P>0.05），具有可比性。测量个性化定位组术前胫骨冠状位近、远端解剖轴形成的侧弓角（tibial bowing angle，TBA）并对胫骨轴线分型，分析个性化定位点位置分布规律。比较两组手术前后髋-膝-踝角（hip-knee-ankle angle，HKA）、胫骨远端外侧角（lateral distal tibial angle，LDTA），术后冠状位胫骨假体角（tibia component angle，TCA）及胫骨假体冠状位力线优良率。.
结果: 个性化定位组胫骨轴线分为直线型58膝（50.88%）、内弓型35膝（30.70%）、外弓型21膝（18.42%）。直线型者胫骨个性化定位点多位于外侧髁间棘高点（62.07%），内弓型者多位于内、外侧髁间棘之间区域（51.43%），外弓型者多位于外侧髁间棘外侧坡（57.14%）。两组组内手术前后HKA比较，差异均有统计学意义（ P<0.05）；手术前后LDTA比较，差异均无统计学意义（ P>0.05）。两组间术前LDTA、HKA及手术前后差值比较，差异均无统计学意义（ P>0.05）；术后TCA比较，差异有统计学意义（ P<0.05）。传统定位组术后胫骨平台假体较个性化定位组更倾向于内翻。术后个性化髓外定位组胫骨假体冠状位力线优良率为96.5%（110/114），传统定位组为87.5%（84/96），差异有统计学意义（ χ 2=7.652， P=0.006）。.
结论: TKA胫骨侧冠状位截骨时采用个性化髓外定位技术可行，与传统髓外定位技术相比胫骨假体冠状位力线优良率更高。.
Keywords: Total knee arthroplasty; coronal alignment; personalized extramedullary positioning technique; tibial prosthesis.