Lombardi Adolph V, Berend Keith R, Ng Vincent Y
Joint Implant Surgeons, Inc, 7277 Smith's Mill Rd, Ste 200, New Albany, OH 43054, USA.
Orthopedics. 2011 Sep 9;34(9):e504-6. doi: 10.3928/01477447-20110714-40.
Restoration of an overall neutral mechanical axis has been a long-held tenet in total knee arthroplasty (TKA). Numerous biomechanical, finite element, and clinical studies have demonstrated that coronal malalignment, particularly varus, is associated with increased strain, higher failure rates, and, in some cases, poorer outcomes. With advances in computer-assisted navigation, 3-dimensional imaging, and patient-specific positioning guides, the potential for greater precision in bone resection and component positioning has rekindled interest in this important issue. Several recently published studies demonstrating no difference in survivorship for malaligned TKAs have challenged the concept of an alignment safe zone. Some surgeons have discussed a paradigm shift in defining optimal alignment. While we agree that compared to several decades ago, there is greater understanding of TKA kinematics and that broad targets for alignment may not impart significant benefit as a dichotomous variable, there are multiple reasons why neutral alignment and classic bone cuts remain valid and important in delivering a successful TKA. In comparison to the preponderance of evidence advocating a neutral mechanical axis and approximately 5° to 7° valgus anatomic alignment, there is insufficient support for reasonably choosing any other target. Although technology has improved surgical precision, it has not eliminated the human factor, and aiming for neutral provides the safest margin for error. The foremost objective of TKA is a durable and well-functioning joint, not necessarily one that replicates normal or the patient's native condition. While the latter goal is certainly desirable, the priority of the former should never be overlooked.
恢复整体中立的机械轴线一直是全膝关节置换术（TKA）中长期秉持的原则。大量生物力学、有限元及临床研究表明，冠状面排列不齐，尤其是内翻，与应变增加、更高的失败率相关，在某些情况下，还与较差的预后有关。随着计算机辅助导航、三维成像及患者特异性定位导板的发展，在骨切除和假体定位方面实现更高精度的可能性重新引发了人们对这一重要问题的关注。最近发表的几项研究表明，排列不齐的全膝关节置换术在生存率方面并无差异，这对排列安全区的概念提出了挑战。一些外科医生讨论了在定义最佳排列方面的范式转变。虽然我们同意，与几十年前相比，人们对全膝关节置换术的运动学有了更深入的了解，而且作为一个二分变量，宽泛的排列目标可能不会带来显著益处，但中立排列和经典截骨在成功实施全膝关节置换术中仍然有效且重要，原因有多个。与主张中立机械轴线和大约5°至7°外翻解剖排列的大量证据相比，没有足够的支持来合理选择任何其他目标。尽管技术提高了手术精度，但它并未消除人为因素，以中立为目标能提供最安全的误差范围。全膝关节置换术的首要目标是一个持久且功能良好的关节，不一定是复制正常或患者原生状况的关节。虽然后一个目标当然是可取的，但绝不能忽视前一个目标的优先级。
