Department of Orthopaedic Surgery, Phra Nakhon Si Ayutthaya Hospital, Ayutthaya, Thailand.
Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Clin Orthop Surg. 2023 Aug;15(4):597-605. doi: 10.4055/cios22106. Epub 2022 Nov 30.
Femorotibial rotational mismatch can occur when there is a rotational malalignment in either the tibial or femoral component. Self-aligned technique was proposed for orienting the tibial component in relation to the femoral prosthesis to reduce rotational malalignment between components. Therefore, we aimed to compare the rotational angle of the femoral and tibial components, as well as the femorotibial rotational mismatch, between the measured resection (MR) and gap-balancing (GB) techniques when combined with a self-aligned technique.
We conducted a nonrandomized, experimental study with 50 patients in each group. The femoral rotation was set to 3° external rotation relative to the posterior condylar axis in the MR group, whereas the femur was resected to obtain an optimal rectangular flexion gap in the GB group. The self-aligned method was used to set the tibial rotation in both groups. Femoral and tibial rotational alignments were evaluated compared to a surgical transepicondylar axis of the femur using computed tomography. Rotational mismatch was defined as a difference between the femoral and tibial rotational alignments. A positive value indicated that the component was externally rotated relative to the reference line.
The femoral component of the GB group was more externally rotated than that of the MR group (1.52° ± 1.31° vs 0.28° ± 1.16°, < 0.001). However, the tibial rotational angle was not statistically significantly different between the MR and GB groups (1.28° ± 3.17° vs. 1.86° ± 2.81°, = 0.220), and the rotational mismatch was 1.00° ± 3.28° and 0.34° ± 2.71°, respectively ( = 0.306).
Although the femoral component of the GB group had a greater degree of external rotation than that of the MR group, the use of a self-aligned technique for tibial component placement resulted in no significant difference in tibial rotational alignment or rotational mismatch. This technique helps align the tibial component with the femoral component and lessen the degree of rotational malalignment in both the MR and GB techniques.
当胫骨或股骨部件存在旋转对线不良时，可能会出现股胫旋转不匹配。自对准技术是为了在股骨假体中定向胫骨部件，以减少部件之间的旋转对线不良。因此，我们旨在比较在结合自对准技术时，测量切除（MR）和间隙平衡（GB）技术之间股骨和胫骨部件的旋转角度，以及股胫旋转不匹配。
我们进行了一项非随机、实验性研究，每组 50 例患者。在 MR 组中，股骨旋转设定为相对于后髁轴外旋 3°，而在 GB 组中，股骨被切除以获得最佳的矩形屈曲间隙。在两组中都使用自对准方法设置胫骨旋转。使用计算机断层扫描评估股骨的外科后髁间轴与股骨和胫骨旋转对准的比较。旋转不匹配定义为股骨和胫骨旋转对准之间的差异。正值表示相对于参考线的部件外旋。
GB 组的股骨部件比 MR 组更向外旋转（1.52°±1.31°比 0.28°±1.16°，<0.001）。然而，MR 和 GB 组之间的胫骨旋转角度没有统计学上的显著差异（1.28°±3.17°比 1.86°±2.81°，=0.220），旋转不匹配分别为 1.00°±3.28°和 0.34°±2.71°（=0.306）。
尽管 GB 组的股骨部件具有更大的外旋程度，但使用自对准技术放置胫骨部件不会导致胫骨旋转对准或旋转不匹配的显著差异。该技术有助于使胫骨部件与股骨部件对准，并减轻 MR 和 GB 技术中旋转对线不良的程度。
