Sporthopaedicum Straubing, Bahnhofplatz 8, 94315 Straubing, Germany.
Knee Surg Sports Traumatol Arthrosc. 2011 Sep;19(9):1488-95. doi: 10.1007/s00167-011-1462-8. Epub 2011 Mar 23.
The objective of this prospective, randomized, patient- and observer-blinded study was to analyze, in vivo, the knee joint kinematics in the sagittal plane in a patient population that had received either a fixed or a mobile TKA.
Thirty-one patients (57 knees) were evaluated by means of fluoroscopy during unloaded flexion and extension against gravity as well as during step up and step down with full weight bearing. In these 31 patients, 22 fixed-bearing TKAs, 16 mobile-bearing TKAs, and 19 natural knee joints were included. Fluoroscopic radiographs were evaluated by measuring the "patella tendon angle" in relation to the knee flexion angle, as a measure of anteroposterior translation, as well as the "kinematic index," as a measure of reproducibility.
During unloaded movement, fluoroscopic analysis did not show a significant difference between both types of prosthesis design and the natural knee. In the weight-bearing movement, both types of TKA designs revealed a more linear patellar tendon angle curve, with a greater angle in extension and in flexion than in the natural knees. In the mobile-bearing group, interindividual deviations from the mean during weight-bearing movements were significantly less than in the fixed-bearing group.
No functional advantage of mobile-bearing TKA over fixed-bearing devices could be found. Both TKA designs showed the typical kinematics of an anterior instability. These results only apply to cruciate retaining mobile-bearing TKA with a bearing that allows both rotation and anteroposterior translation, using a sagittal plane kinematics analysis evaluated by such methodology. A possible influence of less variability of the kinematic pattern on clinical results still needs to be confirmed.
本前瞻性、随机、患者和观察者双盲研究的目的是分析接受固定或活动 TKA 治疗的患者人群中膝关节在矢状面的关节运动学。
通过透视对 31 例患者（57 膝）进行评估，包括在不受载情况下进行膝关节屈伸运动以及在完全负重情况下进行上下台阶运动。在这 31 例患者中，包括 22 例固定衬垫 TKA、16 例活动衬垫 TKA 和 19 例自然膝关节。通过测量“髌腱角”相对于膝关节屈曲角度，作为前后平移的测量指标，以及“运动学指数”，作为可重复性的测量指标，对透视射线照片进行评估。
在不受载运动中，两种类型的假体设计与自然膝关节之间的透视分析没有显示出显著差异。在负重运动中，两种类型的 TKA 设计都显示出更线性的髌腱角曲线，在伸展和屈曲时的角度大于自然膝关节。在活动衬垫组中，负重运动时个体与平均值的偏差明显小于固定衬垫组。
没有发现活动衬垫 TKA 相对于固定衬垫装置的功能优势。两种 TKA 设计都显示出典型的前向不稳定的运动学特征。这些结果仅适用于保留交叉韧带的、允许旋转和前后平移的、使用这种方法评估的矢状面运动学分析的活动衬垫 TKA。运动学模式的可变性较小对临床结果的可能影响仍需确认。
