Faschingbauer Martin, Hambrecht Jakob, Schwer Jonas, Martin John R, Reichel Heiko, Seitz Andreas
Department of Orthopedic Surgery, RKU, University of Ulm, Ulm, Germany.
Institute of Orthopaedic Research and Biomechanics, University of Ulm, Ulm, Germany.
Bone Jt Open. 2024 Jul 18;5(7):592-600. doi: 10.1302/2633-1462.57.BJO-2024-0033.R1.
Patient dissatisfaction is not uncommon following primary total knee arthroplasty. One proposed method to alleviate this is by improving knee kinematics. Therefore, we aimed to answer the following research question: are there significant differences in knee kinematics based on the design of the tibial insert (cruciate-retaining (CR), ultra-congruent (UC), or medial congruent (MC))?
Overall, 15 cadaveric knee joints were examined with a CR implant with three different tibial inserts (CR, UC, and MC) using an established knee joint simulator. The effects on coronal alignment, medial and lateral femoral roll back, femorotibial rotation, bony rotations (femur, tibia, and patella), and patellofemoral length ratios were determined.
No statistically significant differences were found regarding coronal alignment (p = 0.087 to p = 0.832). The medial congruent insert demonstrated restricted femoral roll back (mean medial 37.57 mm; lateral 36.34 mm), while the CR insert demonstrated the greatest roll back (medial 42.21 mm; lateral 37.88 mm; p < 0.001, respectively). Femorotibial rotation was greatest with the CR insert with 2.45° (SD 4.75°), then the UC insert with 1.31° (SD 4.15°; p < 0.001), and lowest with the medial congruent insert with 0.8° (SD 4.24°; p < 0.001). The most pronounced patella shift, but lowest patellar rotation, was noted with the CR insert.
The MC insert demonstrated the highest level of constraint of these inserts. Femoral roll back, femorotibial rotation, and single bony rotations were lowest with the MC insert. The patella showed less shifting with the MC insert, but there was significantly increased rotation. While the medial congruent insert was found to have highest constraint, it remains uncertain if this implant recreates native knee kinematics or if this will result in improved patient satisfaction.
初次全膝关节置换术后患者不满意的情况并不少见。一种缓解这种情况的方法是改善膝关节运动学。因此，我们旨在回答以下研究问题：基于胫骨假体（保留交叉韧带（CR）、超匹配（UC）或内侧匹配（MC））的设计，膝关节运动学是否存在显著差异？
总体而言，使用已建立的膝关节模拟器，对15个尸体膝关节进行检查，使用带有三种不同胫骨假体（CR、UC和MC）的CR植入物。确定其对冠状位对线、股骨内外侧后滚、股胫旋转、骨旋转（股骨、胫骨和髌骨）以及髌股长度比的影响。
在冠状位对线方面未发现统计学显著差异（p = 0.087至p = 0.832）。内侧匹配假体显示股骨后滚受限（平均内侧37.57毫米；外侧36.34毫米），而CR假体显示最大后滚（内侧42.21毫米；外侧37.88毫米；p分别<0.001）。CR假体的股胫旋转最大，为2.45°（标准差4.75°），其次是UC假体，为1.31°（标准差4.15°；p < 0.001）；内侧匹配假体最低，为0.8°（标准差4.24°；p < 0.001）。CR假体观察到最明显的髌骨移位，但髌骨旋转最低。
MC假体在这些假体中表现出最高的限制水平。MC假体的股骨后滚、股胫旋转和单一骨旋转最低。MC假体的髌骨移位较少，但旋转显著增加。虽然发现内侧匹配假体具有最高的限制，但尚不确定该植入物是否能重现天然膝关节运动学，或者这是否会提高患者满意度。
