Laboratorio di Biomeccanica ed Innovazione Tecnologica, IRCCS Istituto Ortopedico Rizzoli, via di Barbiano 1/10, 40136, Bologna, BO, Italy.
Clinica Ortopedica e Traumatologica II, IRCCS Istituto Ortopedico Rizzoli, via Pupilli 1, 40136, Bologna, BO, Italy.
Knee Surg Sports Traumatol Arthrosc. 2020 Sep;28(9):2883-2892. doi: 10.1007/s00167-019-05645-6. Epub 2019 Aug 3.
Which total knee arthroplasty (TKA) design represents the better solution to restore a correct knee biomechanics is still debated. The aim of this study was to compare posterior stabilized (PS) and cruciate retaining (CR) version of the same TKA design (femoral component with an anatomic sagittal radius-J-curve design) by the use of dynamic Roentgen stereophotogrammetric analysis (RSA). The hypothesis was that the two models influence differently in vivo knee kinematic.
A cohort of 16 randomly selected patients was evaluated 9 months after surgery: Zimmer PERSONA® was implanted, eight with CR design and eight with PS design. The kinematic evaluations were performed using a Dynamic RSA (BI-STAND DRX 2) developed in our Institute, during the execution of the sit-to-stand motor task. The motion parameters were obtained using the Grood and Suntay decomposition and the low-point kinematics methods.
PS TKA lateral femoral compartment had a wider anterior translation (17 ± 2 mm) than the medial one (11 ± 2 mm), while the two compartments of CR TKA showed a similar anterior translation (medial: 9 ± 2 mm/lateral: 11 ± 2 mm). T test for comparison between CR and PS TKA of antero-posterior translation showed a statistically significant difference (p < 0.05) in the flexion range between 15° and 40°. The CR prosthesis did not anteriorly translate during flexion. The PS design translated anteriorly showing a roll-forward mechanism during extension from 80° to 18° of flexion and a posterior translation from 18° to 0°. The same significant differences (p < 0.05) between the PS and CR groups were found comparing the low-point positions of the femoral condyles in the range of flexion between 25° and 40° for the medial compartment and between 15° and 25° for the lateral compartment.
Dynamic RSA was able to investigate for the first time in vivo the kinematic behaviour of PS and CR version of the same TKA J-curve design. PS type showed a medial pivot during sit-to-stand motion task, while the CR type showed a cylindrical movement. Further studies are needed to evaluate the impact of different TKA designs on clinical results.
IV.
哪种全膝关节置换术（TKA）设计更能恢复正确的膝关节生物力学仍存在争议。本研究旨在通过动态放射立体摄影分析（RSA）比较同一种 TKA 设计（具有解剖矢状半径-J 曲线设计的股骨组件）的后稳定（PS）和前交叉韧带保留（CR）版本。假设这两种模型以不同的方式影响体内膝关节运动学。
本研究纳入了 16 名随机选择的患者，在术后 9 个月进行评估：植入 Zimmer PERSONA®，其中 8 例为 CR 设计，8 例为 PS 设计。使用我们研究所开发的动态 RSA（BI-STAND DRX 2）进行运动学评估，在执行从坐到站的运动任务时进行。运动参数使用 Grood 和 Suntay 分解和低点运动学方法获得。
PS TKA 外侧股骨间室的前向平移（17±2mm）比内侧间室（11±2mm）更宽，而 CR TKA 的两个间室显示出相似的前向平移（内侧：9±2mm/外侧：11±2mm）。CR 和 PS TKA 的前后平移比较的 T 检验显示，在 15°至 40°的弯曲范围内有统计学意义上的差异（p<0.05）。CR 假体在弯曲过程中没有向前平移。PS 设计向前平移，在从 80°到 18°的伸展过程中显示出滚向前的机制，从 18°到 0°的后移。在 25°至 40°的弯曲范围内，内侧间室和 15°至 25°的外侧间室，PS 和 CR 组之间也发现了相同的显著差异（p<0.05），比较了股骨髁的低点位置。
动态 RSA 首次能够在体内研究同一种 TKA J 曲线设计的 PS 和 CR 版本的运动学行为。PS 型在从坐到站的运动任务中表现为内侧枢轴，而 CR 型表现为圆柱运动。需要进一步研究以评估不同 TKA 设计对临床结果的影响。
IV。
