Huddleston James I, Scott Richard D, Wimberley David W
Orthopaedic Biomechanics and Biomaterials Laboratory, Massachusetts General Hospital, Boston, MA 02114, USA.
Clin Orthop Relat Res. 2005 Nov;440:101-6. doi: 10.1097/01.blo.0000185448.43622.77.
Use of a fixed anatomic landmark to set rotation of the tibial component may lead to rotational malalignment. Post wear in stabilized components, backside wear in any conforming modular system, and patellar maltracking may result from tibiofemoral rotational incongruence. We aimed to quantify tibial rotational alignment in 109 primary rotating platform TKAs. After trial components were inserted with the knee properly balanced, we recorded the neutral point of the rotating tibial insert, in extension, relative to the most medial aspect of the tibial tubercle. We hypothesized that all neutral points would lie within 10 degrees of the mean. Divergence of the neutral point was recorded as being internal or external to the medial border of the tibial tubercle to the nearest 5 degrees increment. Our results showed a mean divergence of 5 degrees +/- 5 degrees external to the medial border of the tubercle. Five percent of knees, however, had neutral points > or = 10 degrees from the mean. Surgeons who use fixed-bearing modular components with any rotational constraint must be cautious in choosing a fixed anatomic tibial landmark to determine the rotational alignment of the tibial component. Doing so may create tibiofemoral rotational malalignment in full extension that may lead to suboptimal outcomes.
Diagnostic study, Level II-3. See the Guidelines for Authors for a complete description of levels of evidence.
使用固定的解剖标志来设定胫骨部件的旋转可能会导致旋转排列不齐。稳定部件的磨损后、任何顺应性模块化系统中的后侧磨损以及髌股轨迹异常可能由胫股旋转不一致引起。我们旨在量化109例初次旋转平台全膝关节置换术中胫骨的旋转排列。在试验部件插入且膝关节正确平衡后，我们记录了伸直位时旋转胫骨衬垫相对于胫骨结节最内侧的中性点。我们假设所有中性点都在平均值的10度范围内。中性点的偏差记录为相对于胫骨结节内侧边界的内侧或外侧，精确到最接近的5度增量。我们的结果显示，相对于结节内侧边界，平均偏差为外侧5度±5度。然而，5%的膝关节中性点与平均值相差≥10度。使用带有任何旋转约束的固定承重模块化部件的外科医生在选择固定解剖胫骨标志来确定胫骨部件的旋转排列时必须谨慎。这样做可能会在完全伸直时造成胫股旋转排列不齐，从而导致不理想的结果。
诊断性研究，II-3级。有关证据水平的完整描述，请参阅作者指南。
