Department of Orthopaedics, The Ohio State University Medical Center, Columbus, OH, USA.
Clin Orthop Relat Res. 2012 Jan;470(1):99-107. doi: 10.1007/s11999-011-1996-6.
Coronal malalignment occurs frequently in TKA and may affect implant durability and knee function. Designed to improve alignment accuracy and precision, the patient-specific positioning guide is predicated on restoration of the overall mechanical axis and is a multifaceted new tool in achieving traditional goals of TKA.
QUESTIONS/PURPOSES: We compared the effectiveness of patient-specific positioning guides to manual instrumentation with intramedullary femoral and extramedullary tibial guides in restoring the mechanical axis of the extremity and achieving neutral coronal alignment of the femoral and tibial components.
We retrospectively reviewed 569 TKAs performed with patient-specific positioning guides and 155 with manual instrumentation by two surgeons using postoperative long-leg radiographs. For all patients, we assessed the zone in which the overall mechanical axis passed through the knee, and for one surgeon's cases (105 patient-specific positioning guide, 55 manual instrumentation), we also measured the hip-knee-ankle angle and the individual component angles with respect to their mechanical axes.
The overall mechanical axis passed through the central third of the knee more often with patient-specific positioning guides (88%) than with manual instrumentation (78%). The overall mean hip-knee-ankle angle for patient-specific positioning guides (180.6°) was similar to manual instrumentation (181.1°), but there were fewer ± 3° hip-knee-ankle angle outliers with patient-specific positioning guides (9%) than with manual instrumentation (22%). The overall mean tibial (89.9° versus 90.4°) and femoral (90.7° versus 91.3°) component angles were closer to neutral with patient-specific positioning guides than with manual instrumentation, but the rate of ± 2° outliers was similar for both the tibia (10% versus 7%) and femur (22% versus 18%).
Patient-specific positioning guides can assist in achieving a neutral mechanical axis with reduction in outliers.
在 TKA 中经常会出现冠状面对线不良的情况，这可能会影响植入物的耐久性和膝关节功能。患者特异性定位导向器的设计目的是提高对线的准确性和精度，其前提是恢复整体机械轴，并且是实现 TKA 传统目标的一种多方面的新工具。
问题/目的：我们比较了患者特异性定位导向器与髓内股骨和髓外胫骨导向器在恢复肢体机械轴和实现股骨和胫骨组件中立冠状对线方面的有效性。
我们回顾性地审查了 569 例由两位外科医生使用患者特异性定位导向器和 155 例手动仪器进行的 TKA，术后进行了下肢全长 X 线片检查。对于所有患者，我们评估了整个机械轴穿过膝关节的区域，对于一位外科医生的病例（105 例患者特异性定位导向器，55 例手动仪器），我们还测量了髋膝踝角以及各组件相对于其机械轴的角度。
患者特异性定位导向器（88%）比手动仪器（78%）更常使整个机械轴穿过膝关节的中央三分之一。患者特异性定位导向器的总体平均髋膝踝角（180.6°）与手动仪器相似（181.1°），但患者特异性定位导向器的±3°髋膝踝角离群值（9%）少于手动仪器（22%）。患者特异性定位导向器的总体平均胫骨（89.9°对 90.4°）和股骨（90.7°对 91.3°）组件角度比手动仪器更接近中立，但胫骨（10%对 7%）和股骨（22%对 18%）的±2°离群值发生率相似。
患者特异性定位导向器可以辅助实现中立机械轴，减少离群值。
