Department of Mechanical, Aerospace & Biomedical Engineering, University of Tennessee, 301 Perkins Hall, 1506 Middle Drive, Knoxville, TN, 37996, USA,
Clin Orthop Relat Res. 2014 Jan;472(1):248-53. doi: 10.1007/s11999-013-3105-5.
Previous in vivo fluoroscopy studies have documented that axial rotation for patients having a TKA was significantly less than those having a normal knee. In fact, many subjects having a TKA experience a reverse axial rotation pattern where the femur internally rotates with increasing flexion. However, no previous studies have been conducted to determine if this reverse axial rotation pattern affects TKA performance.
QUESTIONS/PURPOSES: The purposes of this study were: (1) Do normal and reverse axial rotation patterns of a TKA affect the maximum flexion angle postoperatively? (2) Does the axial rotation angle of the knee at maximum flexion during weightbearing impact the magnitude of the maximum flexion achieved in weightbearing?
One hundred twenty patients having TKA, previously analyzed under in vivo conditions using fluoroscopy and a three-dimensional model-fitting software package, were further evaluated to determine if reverse axial rotation patterns limit weightbearing TKA flexion. In this retrospective cohort, we identified 58 patients who had a normal axial rotation pattern (greater than 15° normal rotation). Sixty-two patients experienced greater than 3° of reverse axial rotation, defined as internal rotation of the femur relative to the tibia.
Patients having a normal axial rotation achieved greater weightbearing knee flexion than those with reverse axial rotation (115° versus 109°, p = 0.02). Additionally, patients with greater than 3° of normal axial rotation at maximum flexion had more flexion than those with less than 3° of normal axial rotation at ending flexion (115° versus 107°, p < 0.001).
These findings show reverse axial rotation and a smaller magnitude of normal axial rotation reduce weightbearing knee flexion. This is likely the result of increased posterior movement of the lateral condyle and is an important consideration in future implant designs.
先前的体内透视研究已经证明，接受 TKA 的患者的轴向旋转明显小于正常膝关节的患者。实际上，许多接受 TKA 的患者会出现反向轴向旋转模式，即随着屈曲度的增加股骨内旋。然而，目前尚无研究确定这种反向轴向旋转模式是否会影响 TKA 的性能。
问题/目的：本研究的目的是：（1）TKA 的正常和反向轴向旋转模式是否会影响术后最大屈曲角度？（2）在负重时最大屈曲时膝关节的轴向旋转角度是否会影响负重时达到的最大屈曲程度？
120 例接受 TKA 的患者先前在体内条件下使用透视和三维模型拟合软件包进行了分析，进一步评估以确定反向轴向旋转模式是否会限制负重 TKA 的屈曲。在这项回顾性队列研究中，我们确定了 58 例具有正常轴向旋转模式（大于 15°正常旋转）的患者。62 例患者出现大于 3°的反向轴向旋转，定义为股骨相对于胫骨的内旋。
具有正常轴向旋转的患者在负重时的膝关节屈曲度大于具有反向轴向旋转的患者（115°比 109°，p = 0.02）。此外，在最大屈曲时轴向旋转大于 3°的患者比在终末屈曲时轴向旋转小于 3°的患者具有更大的屈曲度（115°比 107°，p<0.001）。
这些发现表明，反向轴向旋转和较小的正常轴向旋转幅度会减少负重时的膝关节屈曲度。这很可能是由于外侧髁向后移动增加所致，在未来的植入物设计中应予以考虑。
