Scientific Evaluation of a New Alignment Method for Total Knee Arthroplasty

PI：Hull，Maury L.建议编号：1067527目标和目的：本研究的总体目的是通过体外测试来确定在全膝关节置换术(TKA)中，运动对齐是一种有争议的新对齐方法，它是否比传统的对齐方法--机械对齐--能提供更好的膝关节功能。这两种对齐方法将通过确定哪种方法更好地将胫股关节的运动轴恢复到正常、被动运动包络恢复到正常、更均匀地平衡胫骨组件上的内侧和外侧接触力并将其集中在胫骨假体上进行评估。这四大类因变量是膝关节功能的重要决定因素，必须在体外进行测试，因为在体内使用这种复杂程度的器械是不可能的。这项拟议的研究将检验以下四个假设：1)与机械对齐TKA相比，运动对齐TKA恢复了胫骨弯曲和伸展所围绕的股骨横轴和胫骨内外旋转所围绕的胫骨纵向旋转轴的位置和方向。2)主动对准的TKA较机械对准的TKA恢复了屈伸、内翻、内外旋和前后平移被动运动包络的中性和双向极限。3)运动对准的TKA比机械对准的TKA能更好地平衡内侧和外侧间隙的接触力。4)运动对准的TKA比机械对准的TKA更能集中内侧和外侧的接触力。我们的研究团队能够进行这些研究是独一无二的，因为我们开发了一种确定运动轴的新方法，我们有使用我们定制的六自由度负载应用膝关节测试系统的经验，我们在运动学和机械对准的TKA方面拥有丰富的开发和临床经验。智力价值：对齐全膝关节置换术的方法对患者和外科医生来说是非常重要的，因为对齐决定膝关节的运动、稳定性、疼痛缓解、患者满意度、耐用性和翻修率。力争达到0°机械轴的机械对准TKA具有良好的长期耐用性，但多项研究表明，20%-25%的患者由于持续的不明原因的疼痛、僵硬和不稳定而不满意。结果不太令人满意的一个原因是，将肢体与0°机械轴对齐会改变膝盖的运动学。运动学上的变化需要释放韧带来恢复运动，这可能会导致不稳定。运动学对齐是一种有争议但令人兴奋的新方法，它努力将膝关节的运动学恢复到正常，在这种情况下不需要韧带松解。与机械对准的TKA相比，运动对准的TKA提高了患者满意度，缩短了手术时间，减少了输血，并加快了恢复。运动轴、被动运动包膜和接触力的体外评估将为不同方法之间的临床结果差异提供量化的解释。更广泛的影响：全膝关节置换术(TKA)是一种用于减轻疼痛、恢复关节功能和改善膝骨性关节炎(OA)患者生活质量的外科手术。2006年，美国进行了542,000例TKA手术，预计到2030年，每年将进行348万例TKA手术。因为20-25%的患者不太满意[5，45]，所以有必要改善临床结果，并需要降低与翻修手术相关的发病率和费用。如果拟议的体外身体研究确定，运动学对齐的TKA更好地恢复了股骨的横轴、被动运动包络、接触力的分布，并更好地将接触力居中，那么这种对齐技术在体内的使用将进一步得到证明。运动学全膝关节置换术的广泛应用将可能转化为临床结果的改善，翻修率的降低，以及未来20年将接受全膝关节置换术的数千万患者的社会和医疗成本的降低。

PI: Hull, Maury L.Proposal Number: 1067527Goals and Objectives: The general aim of the proposed research is to use in vitro testing to determine whether kinematic alignment, which is a controversial new method of aligning components in total knee arthroplasty (TKA), gives better knee function than mechanical alignment, which is the traditional method of alignment. The two alignment methods will be assessed by determining which better restores the kinematic axes of the tibiofemoral joint to normal, the passive envelopes of motion to normal, more evenly balances and centers the medial and lateral contact forces on the tibial component. These four general categories of dependent variables are important determinates of knee function, which must be tested in vitro because the use of instrumentation with this level of sophistication in vivo is not possible. The proposed research will test the following four hypotheses: 1) Kinematically aligned TKA restores the position and orientation of both the transverse axis in the femur about which the tibia flexes and extends and the longitudinal rotational axis in the tibia about which the tibia internally and externally rotates closer to normal than mechanically aligned TKA. 2) Kinematically aligned TKA restores the neutral and bidirectional limits of the passive envelopes of motion of flexion-extension, varus-valgus, and internal-external rotations and anterior-posterior translation closer to normal than mechanically aligned TKA. 3) Kinematically aligned TKA better balances the contact forces in the medial and lateral compartments than mechanically aligned TKA. 4) Kinematically aligned TKA better centers the contact forces in the medial and lateral compartments than mechanically aligned TKA. Our research group is uniquely able to perform these studies because we have developed a new method for determining the axes of motion, we have experience using our custom built six degree-of-freedom load application knee testing system, and we have extensive developmental and clinical experience with kinematically and mechanically aligned TKAs. Intellectual Merit: The method of aligning a TKA is of keen interest to the patient and surgeon because alignment determines knee motion, stability, pain relief, patient satisfaction, durability, and revision rate. Mechanically aligned TKA, which strives to achieve a 0° mechanical axis, has good long-term durability, but several studies have shown that 20-25% of patients are less than satisfied due to persistent unexplained pain, stiffness, and instability. One reason for the less than satisfied outcome is that aligning the limb to a 0º mechanical axis changes the kinematics of the knee. The change in kinematics requires ligament releases to restore motion, which can cause instability. Kinematic alignment is a controversial but exciting new method that strives to restore the kinematics of the knee to normal in which case ligament releases are not required. Kinematically aligned TKA has increased patient satisfaction, shortened surgery, reduced transfusions, and quickened recovery compared to mechanically aligned TKA. The in vitro assessment of axes of motion, passive envelopes of motion, and contact forces will provide quantifiable explanations for the differences in clinical results between methods. Broader Impact: Total knee arthroplasty (TKA) is a surgical procedure used to reduce pain, restore joint function, and improve the quality of life of patients suffering from osteoarthritis (OA) of the knee. In 2006, 542,000 TKA procedures were performed in the US, and it has been projected that by 2030, 3.48 million TKA procedures will be performed annually. Because 20-25% of patients are less than satisfied [5, 45], there is a need to improve the clinical outcome and a need to reduce the morbidity and expense associated with revision surgery. If the proposed in vitro cadaveric study determines that kinematically aligned TKA better restores the transverse axis in the femur, passive envelopes of motion, distribution of contact forces, and better centers the contact forces, then the use of this alignment technique in vivo would be further justified. The broad impact of the increased use of kinematically TKA would likely translate into improved clinical outcome, a reduction in the revision rate, and reduction in the social and medical costs for the tens of millions of patients that will undergo TKA in the next two decades.