Nedopil Alexander J., Howell Stephen M., Hull Maury L.
Department of Orthopedic Surgery, Orthopedic Surgeon Adventist Health Lodi Memorial, Lodi, CA, USA
This chapter presents the philosophy of kinematic alignment (KA) and the surgical technique for setting the positions of the components using ten calipered measurements, manual instruments, and nine verification checks. The adoption of KA is increasing. Four meta-analyses, three randomized trials, and a national multicenter study showed that patients treated with KA total knee arthroplasty (TKA) reported significantly better pain relief, function, and flexion and a more normal feeling knee than patients treated with mechanically aligned TKA [1–8]. Two randomized trials that limited the severity of the preoperative knee deformities showed similar clinical outcomes [9, 10]. KA co-aligns the axes of the femoral and tibial components with the three axes of the native knee without restrictions on the level of preoperative deformities [11]. The surgical goal of restoring the native alignments of the limb, Q-angle, and joint lines unique to each patient depends on accurately setting the components coincident to the native joint lines, which co-aligns the axes. The surgical goal of restoring the laxities, tibial compartment forces, knee adduction moment, and gait to those of the native knee without ligament release balances the TKA and promotes long-term implant survival [12–19]. A description of the calipered technique of KA with manual instruments, the sequence for measuring bone positions and resection thicknesses, the intraoperative recording of these measurements on the verification worksheet (Fig. 24.1), and the use of decision trees for balancing the TKA with the medial pivot CS and CR inserts are shown (Figs. 24.2 and 24.3). Calipered measurements of the thicknesses of the femoral and tibial bone resections restore the native joint lines with high reproducibility when they are adjusted within ±0.5 mm of the femoral and tibial components after compensating for cartilage and bone wear and the 1 mm kerf from the saw cut [20–22]. Because calipered measurements are a basic surgical skill, inexpensive, and highly reliable, they should be a required verification check when performing KA with manual instruments, patient-specific guides, navigation, and robotics. Examples of treatment of patients with severe varus and valgus deformities and flexion contractures treated with kinematically aligned TKA without ligament release are shown. Finally, the reasons for the low risk of tibial component failure, low risk of patellofemoral instability, and high implant survival at 10 years after KA TKA are explained [11, 23, 24].
本章介绍了运动学对线（KA）的理念以及使用十项卡尺测量、手动器械和九项验证检查来设置假体组件位置的手术技术。KA的应用正在增加。四项荟萃分析、三项随机试验和一项全国多中心研究表明，与接受机械对线全膝关节置换术（TKA）的患者相比，接受KA-TKA治疗的患者在疼痛缓解、功能、屈曲方面表现明显更好，膝关节感觉更正常[1-8]。两项限制术前膝关节畸形严重程度的随机试验显示了相似的临床结果[9,10]。KA可使股骨和胫骨组件的轴线与天然膝关节的三条轴线共同对线，而不受术前畸形程度的限制[11]。恢复每个患者独特的肢体天然对线、Q角和关节线的手术目标取决于准确设置与天然关节线重合的组件，从而使轴线共同对线。在不进行韧带松解的情况下，将膝关节的松弛度、胫股关节间力、膝关节内收力矩和步态恢复到天然膝关节水平的手术目标可平衡TKA并提高植入物的长期生存率[12-19]。展示了使用手动器械进行KA的卡尺技术、测量骨位置和截骨厚度的顺序、在验证工作表上术中记录这些测量值（图24.1）以及使用决策树通过内侧旋转平台CS和CR垫片平衡TKA（图24.2和24.3）。在补偿软骨和骨磨损以及锯切产生的1mm切口后，当股骨和胫骨组件的厚度在±0.5mm范围内调整时，通过卡尺测量股骨和胫骨截骨厚度可高度可重复地恢复天然关节线[20-22]。由于卡尺测量是一项基本的手术技能，成本低廉且高度可靠，因此在使用手动器械、患者特异性导向器、导航和机器人技术进行KA时，应将其作为一项必需的验证检查。展示了采用运动学对线TKA且不进行韧带松解治疗严重内翻和外翻畸形以及屈曲挛缩患者的病例。最后，解释了KA-TKA术后10年胫骨组件失败风险低、髌股关节不稳定风险低以及植入物生存率高的原因[11,23,24]。
