Orthopaedic Department, CMSC, Charité-University Medicine Berlin, Germany.
Arch Orthop Trauma Surg. 2011 Feb;131(2):163-6. doi: 10.1007/s00402-010-1113-4. Epub 2010 May 18.
In the analysis of painful total knee replacements, the surgical epicondylar axis (SEA) has become established as a standard in the diagnosis of femoral component rotation. It remains unclear whether the gap technique widely used to determine femoral rotation, when applied correctly, results in a rotation parallel to the SEA.
In this prospective study, 69 patients (69 joints) were included who received a navigated bicondylar surface replacement due to primary arthritis of the knee joint.
In 67 cases in which a perfect soft-tissue balancing of the extension gap (<1° asymmetry) was achieved, the flexion gap and the rotation of the femoral component necessary for its symmetry was determined and documented. The femoral component was implanted additionally taking into account the posterior condylar axis and the Whiteside's line. Postoperatively, the rotation of the femoral component to the SEA was determined and this was used to calculate the angle between a femur implanted according to the gap technique and the SEA. If the gap technique had been used consistently, it would have resulted in a deviation of the femoral components by -0.6° ± 2.9° (-7.4°-5.9°) from the SEA. The absolute deviation would have been 2.4° ± 1.8°, with a range between 0.2° and 7.4°.
Even if the extension gap is perfectly balanced, the gap technique does not lead to a parallel alignment of the femoral component to the SEA. Since the clinical results of this technique are equivalent to those of the femur first technique in the literature, an evaluation of this deviation as a malalignment must be considered critically.
在分析疼痛性全膝关节置换术中，外科上髁轴（SEA）已成为诊断股骨组件旋转的标准。目前尚不清楚广泛用于确定股骨旋转的间隙技术，在正确应用时，是否会导致与 SEA 平行的旋转。
在这项前瞻性研究中，纳入了 69 例（69 个关节）因膝关节原发性关节炎接受导航双髁表面置换的患者。
在 67 例实现完美伸膝间隙软组织平衡（<1°不对称）的情况下，确定并记录了屈曲间隙和必要的股骨组件旋转，以使其对称。还考虑了后髁轴和 Whiteside 线来植入股骨组件。术后，确定了股骨组件相对于 SEA 的旋转，并据此计算出根据间隙技术植入的股骨与 SEA 之间的角度。如果一直使用间隙技术，那么股骨组件相对于 SEA 的旋转偏差将为-0.6°±2.9°（-7.4°-5.9°）。绝对偏差为 2.4°±1.8°，范围为 0.2°至 7.4°。
即使伸膝间隙完全平衡，间隙技术也不会导致股骨组件与 SEA 平行对准。由于该技术的临床结果与文献中股骨首先技术的结果相当，因此必须批判性地评估这种偏差是否为对线不良。
